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  • Articles  (407,121)
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  • 1
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    Freshwater Biological Association | Ambleside, UK
    In:  http://aquaticcommons.org/id/eprint/5238 | 1256 | 2011-09-29 15:13:42 | 5238 | Freshwater Biological Association
    Publication Date: 2021-07-09
    Description: This report presents five batches of data which have been despatched to the Joint Research Centre, Ispra. The data as been allocated to various ECDIN (Environmental Chemicals Data and Information Network) files. The data comprises environmental chemicals in the freshwater environment, taking in paricular consideration: aquatic toxicity, bioaccumulation, metabolism and elimination biodegradation.
    Keywords: Chemistry ; Ecology ; Limnology ; Data ; Data processing ; Data collections ; Chemical compounds ; Toxicity ; Bioaccumulation ; Biodegradation ; Metabolism
    Repository Name: AquaDocs
    Type: monograph
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  • 2
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    Freshwater Biological Association | Ambleside, UK
    In:  http://aquaticcommons.org/id/eprint/5293 | 1256 | 2011-09-29 15:08:09 | 5293 | Freshwater Biological Association
    Publication Date: 2021-07-09
    Description: Esthwaite Water is the most productive or eutrophic lake in the English Lake District. Since 1945 its water quality has been determined from weekly or biweekly measurements of temperature, oxygen, plant nutrients and phytoplankton abundance. The lake receives phosphorus from its largely lowland-pasture catchment, sewage effluent from the villages of Hawkshead and Near Sawrey, and from a cage-culture fish farm. From 1986 phosphorus has been removed from the sewage effluent of Hawkshead which was considered to contribute between 47% and 67% of the total phosphorus loading to the lake. At the commencement of phosphorus removal regular measurements of phosphorus in the superficial 0-4 cm layer of lake sediment were made from cores collected at random sites. Since 1986 the mean annual concentration of alkali-extractable sediment phosphorus has decreased by 23%. This change is not significant at the 5% level but nearly so. There has been no marked change in water quality over this period. Summer dominance of blue-green algae which arose in the early 1980s after decline of the previous summer forms, Ceratium spp., has been maintained. Improvement in water quality is unlikely to be achieved at the present phosphorus loading.
    Keywords: Chemistry ; Limnology ; Pollution ; Eutrophication ; Freshwater lakes ; Limnological surveys ; Phosphorus ; Phytoplankton ; Primary production ; Sediment analysis ; Water quality ; England ; Esthwaite Water
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  • 3
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    Iranian Fisheries Science Research Institute | Tehran, Iran
    In:  http://aquaticcommons.org/id/eprint/25179 | 18721 | 2018-09-03 17:23:17 | 25179 | Iranian Fisheries Science Research Institute
    Publication Date: 2021-07-16
    Description: In this study two species of algae, Sargassum glaucescens and Padina boergeseni that found plenteously in Persian Gulf and Bushehr coast, were collected and hot water extracts of them were lyophilized. F. indicus (11.32±1.20 g), after two weeks adaptation in Shoghab research station were immersed in seawater (39 ppt and 25±1 ○C) containing hot-water extract of each brown algae, S.glaucescens and P.boergeseni, at 100, 300 and 500 mg/l concentration, Survival rate and immunological parameters (total haemocyte count (THC), total plasma protein (TPP), Phagocytic activity, bacterial clearance efficiency and bactericidal activity) were examined. In addition effect of dietary administration of beta 1, 3 1, 6 glucan on prevention of White Spot Disease and immunological parameters of shrimp were investigated. According to results, immersion in seawater containing 300 and 500 mg/l concentration of algal hot-water extract after 2 and 3 hours or oral administration of beta 1,3 1,6 glucan at level of 10 g/kg diet for 14 days significantly enhanced THC, TPP, Phagocytic activity, bacterial clearance efficiency and bactericidal activity. Immersion in seawater containing 100, 300 and 500 mg/l hot-water extract of S.glaucescens after 3 hours, improved the survival rate of WSSV-infected F. indicus.
    Keywords: Biology ; Chemistry ; Iran ; Persian Gulf ; Bushehr Province ; Beta-glucan ; Sargassum ; Padina algae ; WSD ; Fenneropenaeus indicus ; Species ; Algae ; Brown Algae ; S.glaucescens ; P.boergeseni ; Survival rate ; White Spot Disease ; Shrimp
    Repository Name: AquaDocs
    Type: monograph
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  • 4
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    Iranian Fisheries Science Research Institute | Tehran, Iran
    In:  http://aquaticcommons.org/id/eprint/25618 | 18721 | 2018-10-07 16:34:53 | 25618 | Iranian Fisheries Science Research Institute
    Publication Date: 2021-07-16
    Description: Chitin and chitosan are 2 very important products of biopolymer that enjoy high consumption in industry, but their production sources are very limited. In this study, Artemia urmiana cyst shells were obtained from previously collected and stored ones in Iranian Artemia Research Center. 20 kg of Artemia urmiana cyst shells were sampled, cleaned, separated, dried and transferred to Iranian Artemia Research Center Laboratory to extract their Chitin and chitosan. Their chitin and chitosan initially were extracted using optimized common chemical methods. Their properties were compared to 2 other types of Chitin and chitosan obtained from crab and shrimp manufactured by Vietnam and China, respectively. To determine their quality, elemental analysis device, infrared spectrophotometry, x –ray radiography, determination of viscosity , molecular weight, crystallinity percent, color, de stylization measure, empirical and molecular formulas were made. The results showed that the percentage of chitin obtained from Artemia cyst Shells in Chemical method was 28 ± 3 % by weight and efficiency into chitosan (grade steel relief) in this method was 50± 5%. To optimize the extraction procedure and the removal of proteins of chitin by biological practices that were done by sodium hydroxide in the chemical method, it was replaced by the bacterium Bacillus subtilis. And in the bio- phase of chitosan de steelation fungus Aspergillus niger enzyme was replaced instead of sodium hydroxide at high temperatures. The results showed that chitin and chitosan can be extracted from Artemia cyst shell using biological method and their characteristics included as in chitin 49.6% C, 8.2 % N, 7.5 % H, and 34.5 %O. Also the same levels for chitosan were 44.4 %, 8.9, 7.2 and 39.5 %, respectively. Their other quality characteristics were included chitin average molecular weight 4.9×10^6 Dalton, crystallinity percentage of 36.4, viscosity at 20°C 31 centipoise and its color was gray to brown. In the biologic method, the average molecular weight of chitosan, crystallinity percentage, viscosity at 20°C, were 5.1×105 Dalton, 94.5, and 18 centipoises, respectively. Also, its color was pale brown. Chemical structure of extracted chitin and chitosan from the shell of Artemia urmiana cysts were C_7H_12NO_4 and C_6H_11 NO_4c, respectively. The comparison of chitin and chitosan obtained from each chemical and biological method revealed that replacing biological methods instead of chemical methods is possible in achieving these products at suitable condition and better quality. This can eliminate the use of chemicals damaging the environment such as sodium hydroxide and decrease environmental pollution.
    Keywords: Biology ; Chemistry ; Iran ; Artemia urmiana cyst shell ; Chitin ; Chitosan ; Chemical ; Biological methods ; Crab shell ; Shrimp shell ; Biotechnology
    Repository Name: AquaDocs
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  • 5
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    Iranian Fisheries Science Research Institute | Tehran, Iran
    In:  http://aquaticcommons.org/id/eprint/25642 | 18721 | 2018-10-14 02:40:17 | 25642 | Iranian Fisheries Science Research Institute
    Publication Date: 2021-07-16
    Description: Padina boergesenii is one of the most abundant brown algae distributed in the north of Persian Gulf and Oman Sea. In this study after sampling and preparation of Padina boergesenii by Chroform-Etanol (3-1) solvent and by Methanol has been extract. Separation and purification of the compounds was carried out using thin layer, general and inverse column chromatography, Cephadex and high-performance liquid chromatography (HPLC). Structural elucidation of the constituents was based on the data obtained from H-NMR, 13C-NMR, HSQC, HMBC, DEPT and Cephadex LH-20. The steroids compounds separated from above alga were identified as 22dehydrocholesterol (1), cholesterol (2), fucosterol (3), β-sitosterol (4), stigmasterol (5), ostreasterol (6) and two epimer of hyroxyestrol(7), based on their spectral data and from comparison with those previously reported in the literature.
    Keywords: Biology ; Chemistry ; Iran ; Oman Sea ; Persian Gulf ; Brown Algae ; Padina boergesenii ; Steroids compounds ; Extraction ; Purification ; Identification ; Amount verification ; Sargassum glaucescens ; Algae ; Abundant ; Sampling ; Chromatography ; Cephadex ; Dehydrocholesterol ; Cholesterol ; Fucosterol ; β-sitosterol ; Stigmasterol ; Ostreasterol
    Repository Name: AquaDocs
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  • 6
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    Iranian Fisheries Science Research Institute | Tehran, Iran
    In:  http://aquaticcommons.org/id/eprint/25792 | 18721 | 2018-10-13 08:54:26 | 25792 | Iranian Fisheries Science Research Institute
    Publication Date: 2021-07-16
    Description: Cheshmehkileh River and adjacent mountainous streams, play a strategic role as a historical axis for anthropogenic civilization, human welfare also habitat and migration pathway of commercial – biologic valuable fishes e.g. Caspian trout, Caspian kuttum, members of Cyprinidae family in south Caspian Sea drainage. Treats such as overfishing of Caspian trout and Red spotted trout stocks in mountainous headwaters, barriers construction and manipulations those are out of river carrying capacity developed by human activities, affected normal function of river as well. Sand mining big factories establishment next to the river, legal and illegal trade of river sediments, direct entry of Tonekabon landfill leakage into the river, development of Rainbow trout farms since 3 decades and huge effluents into the river containing dead fish and types of solids, escapement of cultured Rainbow trouts into the river, … are major minimum factors which needs basic information for integrating inclusively drainage management system. Cheshmehkileh River contains Headwaters of Dohezar (Daryasar & Nusha), Sehezar and Valamroud rivers during 13 monthly sampling phases between September 2009 and October 2010 based on macrozoobenthoses investigations by EPT, EPT/C EPA protocols, measurements of nominated physic-chemical and microbiologic parameters. Probability of Rainbow trouts escapement and invasion, existence, nutrition in Cheshmehkileh environment indeed investigated. Data analysis explained significant differences (P〈0.05) between groups of measured parameters in different sampling stations. Dendogram of clustered analysis based on consolidation of major biologic/ physic-chemical and microbiologic parameters, separated stations No. 1, 3, 2, 4 in one group and remained classified in different groups. Station 8 and 9 similarly separated which expressed general similarities according to Sehezar river environment which were differs in comparison with other stations. Station 11 separated according to its natural quality of water and environment. Similarities between station 10 to Sehezar river stations 8 and 9 expressed general influence of Sehezar River more than Dohezar River in Cheshmehkileh condition especially in station No. 10. High scores of EPT and EPT/C indices in upstream stations 1, 3 and 8 also low score of indices in stations 7, 13 and 6 expressed levels of environment quality between these groups of stations. Maximum average biomass of macroinvertebrates belongs to Trichoptera order in Cheshmehkileh River. Significant decrease of biomass in stations 11, 12 and 13 in comparison with other stations stated environment degradation in mentioned stations relevant to excessive sand mining as well. Pollution resistant groups of invertebrates significantly increased in downstreams against upstream stations. Also disappearing of Plecoptera order in station No. 7, 9, 10 and 13 stated low quality of environment in comparison with upstream stations. Confirmation of effects quality and quantity for point and non-point sources of imported pollutants require specific management considerations in order to present exploitations, pollutants control and emergencies for river monitoring in forthcoming years.
    Keywords: Aquaculture ; Management ; Iran ; Tonekabon ; Cheshmehkileh ; River ; Pollution ; Aquaculture ; EPTC ; Assessment ; Macroinvertebrates ; Chemistry ; Microbiology
    Repository Name: AquaDocs
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  • 7
    Publication Date: 2021-07-16
    Description: In this study, first, the influence of three precooking methods (steaming, oven-baking and microwave-cooking) on the contents of mineral elements-copper, zinc, iron, calcium and sodium-of silver carp (Hypophthalmichthys molitrix) was evaluated. Determination results of evaluated elements in raw fish and cooked samples were in range 3.05 to 4.19 for copper, 71.45 to 82.85 for zinc, 32.18 to 40.70 for iron, 425.6 to 529.46 and 315.5 to 534.76 for calcium. Results showed different precooking treatments had no significant effects on the amounts of mineral elements such as copper, zinc, calcium and sodium. The Iron content in the samples subjected to microwave cooking increased. With doing multivariate analysis, on comparing the raw and precooked fillets, steam cooking found to be the best precooking method on retain mineral elements. After choosing the best precooking method, for evaluating the influence of different filling media including sunflower oil, soybean oil, olive oil and brine, on the quality of canned silver carp, amounts of mineral elements(copper, zinc, iron, calcium and sodium) and microbial indices(total counts, thermopile count and clostridium) and sensory indices (color, smell, taste and texture) was surveyed. Assessments of microbial indices showed no microbial activity in canned products. After canning amounts of sodium increased in all the treatments. Except for iron, using soybean oil had no significant effect on the contents of other elements. The highest levels of iron and copper were observed in olive oil canned samples sterilized at 130°C. Sensory evaluating showed, kind of filling media had no significant effects on sensory indices such as taste, smell and color of canned samples. The texture of soybean oil canned samples and the quality defects of olive oil and brine canned samples had better condition than other treatments. In the last step, canned silver carp were proceed under three different temperatures (115°C, 120°C and 130°C) with equal lethality value (Fo=7min), then sensory indices and amount of mineral elements were compared. Results showed, the contents of iron, copper, sodium and calcium were changed in soybean oil canned sample. The amounts of copper and sodium in sunflower oil canned sample subjected to different heating regimes showed significant variation. The highest amount of copper was observed in the canned samples subjected to 130°C heating regime. Results showed contents of iron and copper of olive oil canned sample subjected to 120°C and 130°C heating regimes were higher than sample subjected to 115°C heating regime, while the zinc and calcium contents had no variation. In brine canned samples the highest amounts of copper and iron was obtained after sterilization in 120°C. Results of sensory evaluation showed different heating regimes had no significant effects on the indices of taste, smell, and color of products. Doing 130°C heating regime in brine canned samples led to obtain the better tenacity of texture. While this heating regime caused to increase the quality defects of soybean oil canned samples as a result of existence of hard parts of bone.
    Keywords: Chemistry ; Fisheries ; Iran ; Precooking ; Filling media ; Heating regime ; Sterilization ; Silver carp ; Mineral elements ; Hypopthalmichthys molitrix ; Samples ; Sunflower oil ; Soybean oil ; Silver Carp
    Repository Name: AquaDocs
    Type: monograph
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  • 8
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    Iranian Fisheries Science Research Institute | Tehran, Iran
    In:  http://aquaticcommons.org/id/eprint/25118 | 18721 | 2018-08-22 02:17:23 | 25118 | Iranian Fisheries Science Research Institute
    Publication Date: 2021-07-16
    Description: Studies show that thyroxine can play an important role in regulating growth and other physiology activities. Since the direct role of thyroxine in growth metamorphose larval of bony fishes hasn't been proved yet, during the experiment accomplished in Shahid Ansari and Jajrood station, the hormones function in the survival of development of silver carp, grass carp and rainbow trout were studied. In this study accomplished of thyroxine baths with 0.1, 0.5 and 1 ppm (with 3 repeat). The other phase, thyroxine injected to females grass carp, silver carp, rainbow trout and barbell of Caspian Sea with different doses (1, 10 and 100 g/g B.W.). Tehn survival of development of embryo and larval and precent of fertilization were studied. Also, the percent of mortality were compared in two phases in stages of development. Results show that: 1) Trout: a) Phase of thyroxine bath: The number of hatching eggs and survival of larval in 0.5 ppm were increased to other treatment. b) Phase of hormone injection: The survival of larval in treatment of 10 g/g was 8.58% that was meaningful difference to other treatment (P〈0.05). 2) Silver carp: a) Phase of thyroxine bath: The number of hatching eggs and survival of larval in 0.5 ppm were (20%) increased to other treatment (P〈0.5). b) Phase of hormone injection: The survival of larval in treatment of 10 g/g was meaningful difference to other treatment (P〈0.05). 3) Grass carp: a) Phase of thyroxine bath: The number of hatching eggs and survival of larval in 0.5 ppm were 39% increased to other treatment. b) Phase of hormone injection: The survival of larval in treatment of 1 g/g was meaningful difference to other treatment (P〈0.05). 4) Barbel of Caspian Sea: Development stages wasn't determined in this fish. Number of eggs degenerated, number of eggs were the first development stages and growth of numbers increased on ovary.
    Keywords: Biology ; Chemistry ; Iran ; Caspian Sea ; Thyroxine ; Female ; Survival ; Growth ; Egg ; Larval ; Grass Carp ; Silver Carp ; Thyroxine (T4)
    Repository Name: AquaDocs
    Type: monograph
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  • 9
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    Iranian Fisheries Science Research Institute | Tehran, Iran
    In:  http://aquaticcommons.org/id/eprint/25713 | 18721 | 2018-10-10 10:11:15 | 25713 | Iranian Fisheries Science Research Institute
    Publication Date: 2021-07-16
    Description: Chitin nanofibers are prepared from the exoskeletons of shrimp by a simple mechanical treatment after a series of purification steps. The nanofibers have fine nanofibers networks with a uniform width of approximately 10 nm. Grinders and highpressure water jet systems are effective for disintegrating chitin into nanofibers. Acidic conditions are the key factor to facilitate mechanical fibrillation. Ultrafine fibers were successfully fabricated chitosan and fish skinextracted gelatin via electrospinning (ES). Important ES parameters, such as concentration of aqueous acid and fish gelatin solutions, and electric field intensity were examined to investigate the effects on the morphology of the gelatin nanofibers. Due to the poor mechanical properties of the fish gelatin membranes, composite nanofibers made of fish gelatin and poly(L-lactide)(PLLA) were produced with a novel solution. The introduction of PLLA remarkably improved the mechanical properties of the gelatin membranes. With a combination of good biocompatibility and mechanical properties, fish gelatin/PLGA blending non-woven mats are considered to be very promising in fish fillet coating application.. in this study, we fabricated a novel nanofibers composed of fish collagen (FC) and polycaprolactone (PCL) blends by using the electrospinning method. Nanofibers were characterized using a scanning electron microscope (SEM), and it was revealed that the diameter of nanofibers decreases as FC content was increased in the FC/PCL composite nanofibers. Several modifications to the chitin NF surface are achieved, including acetylation, deacetylation and maleylation. The results of this study revealed that: 1–It is possible to produce Nanofibers from chitosan and fish gelatin. 2– Covering and coating of processed fish by nanofibers are applicable and increasing the possibility of shell life for the processed fish. 3– Nanofibers which have been produced from chitosan and fish gelation not only is environmentally friendly but also it will be eatable while has been covered for fish fillets. biocompatible chitosan and gelatin made from fish, fresh fish fillets do not have the ability to cover and packaging, but is edible and used.
    Keywords: Biology ; Chemistry ; Fisheries ; Iran ; Chitin ; Chitosan ; Nanofiber ; Chemical modification ; Fish ; Aquatic ; Maintenance
    Repository Name: AquaDocs
    Type: monograph
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  • 10
    Publication Date: 2021-07-16
    Description: This study was conducted to determine phosphorous and nitrogen species at the surface sediment in the southern Caspian Sea (Mazandaran Coast, Kelarabad). Surface sediments samples were collected at three stations from autumn of 2011 to winter of 2012. All samples were prepared by digesting and extracting processes and then phosphorous and nitrogen species concentrations determined using spectroscopy instrument. Results of this study showed that annual mean of Loosely-P, Fe-P, Al-P, Bioava.-P, Ca-P, TIP, Rese.-P and TP was obtained as 5.06±0.33, 55.11±2.52, 42.38±3.74, 102.52±5.68, 172.91±7.12, 275±9.12, 333.30±28.52 and 608±52 µg/g.dw, respectively. The results also showed that inorganic phophorous was less than organic phophorous during different seasons, however, mean percentage of residue-P containing organic compounds and non-degradable compounds was more than 50 percent. Percentage of Ca-P was higher than 60, whereas Bioava.-P was less than 40 percent. In addition, Fe-P and Loosely-P attained the maximum and minimum values, respectively, among the bioavailable phophorous. The order of different forms of phosphorous were recorded as Org-P〉Ca-P〉FeP〉Al-P〉Loosely-P. Annual mean of NH4/N, NO2/N, NO3/N, TIN, TON and TN were observed as 4.23±0.50, 0.06±0.01, 0.74±0.12, 5.02±0.53, 2.48±0.63 and 7.53±0.51 µg/g.dw, respectively. Annual percentage of TIN was two folds than TON and concentration of NH4/N was also four times than NO3/N. As a conclusion, the results revealed that main causes of Bioava.-P adsorption and desorption were temperature, Eh and pH. Also, the form of NH4+/N was of a high percentage because of anaerobic condition in the sediments. According to the high ratios of nitrogen/phosphorous of sediments to nitrogen and phosphorous of bottom water, it finds that released of those from the sediments to water will be happened with high rates. Therefore, it is expected that the establishment of fish farming cages should be carried out with more precautionary approaches which not leads to increased algae bloom.
    Keywords: Biology ; Chemistry ; Ecology ; Iran ; Caspian Sea ; Kelarabad ; Mazandaran coast ; Phophorous ; Nitrogen ; Surface sediment ; Determination ; Breeding
    Repository Name: AquaDocs
    Type: monograph
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  • 11
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    Iranian Fisheries Science Research Institute | Tehran, Iran
    In:  http://aquaticcommons.org/id/eprint/25772 | 18721 | 2018-10-13 08:08:05 | 25772 | Iranian Fisheries Science Research Institute
    Publication Date: 2021-07-16
    Description: Seaweed belonged to baseborn marine plants with cell wall containing of valued polysaccharides such as Agar, Alginate, Limen sulfate and Carmine, used as food additives and in different industries. Base on previous studies, more than 1000 MT. of Sargassum seaweed withdraw from Oman Sea in Sistan and Baluchistan coastal line which can be collect, dried and powdered for using as supplement in shrimp feed. In this project, Sargassum ilicifolium collected from 6 coastal areas, rinsed, dried, powdered and measured the nutritional values in laboratory for surveying statistically. According to the high nutritional value of Tis coastal seaweed, this variety seaweed powder, replaced with protein resources (fish meal and Soy and Wheat) of white-leg shrimp feed which was formulated by Havorash feed factory of Boshehr in four treatments (A: as control without any replacement) B: with 5%, C: 10 % and D: 15% seaweed replacement, each with three replicates in order to obtain isonitrogenus 33% CP., and iso-caloric (13% fat and 15% carbohydrate) feed using winfeed software. The weighed milled ingredients were carefully mixed using a laboratory food mixer. The mixtures were primed with 30% hot water to yield a suitable pulp. Wet diets were made into 2 mm pellet size and dried at 40 °C in a drying cabinet and maintained in standard condition which was used for water stability and absorption capacity test of the pellets in sea water, statistically one way- ANOVA. The Tis coastal seaweed with 9.8% CP, 2% lipid and 23% carbohydrate had higher nutritional value compared to the other gathered seaweed. Also amino acid and fatty acid profiles, vitamins and minerals were measured in all seaweed samples each, with three replications. As result, for using Sargassum ilicifolium as vitamins and mineral premixes in white- leg shrimp feed, Zinc, Cobalt and Phenylalanine with dose of 1.1, 06.0 and 4.0 ml. 100% dried seaweed must be added respectively. The water stability of D feed treatment in seawater (98%) and C (97%) had statistical differences with A and B (95% stability) (P〈0.05). Water absorption capacity of feeds after one hour immersion in seawater showed significance difference between D (110%) and three others, C(100%), B(85% and control(80%) (P〈0.05). As final aim of this project, enriched product of this seaweed as minerals and vitamins supplements were handsel joinery in the Second Medicine Plant Festival, 2016 and registered in recording organization to give the final certificate.
    Keywords: Aquaculture ; Chemistry ; Iran ; Sargassum illicifolium ; Sargassum illicifolium ; Mineral and vitamins supplements ; Natural binder ; Litopenaeus vannamei ; Seaweed ; Vitamin ; White leg shrimp
    Repository Name: AquaDocs
    Type: monograph
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  • 12
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    Iranian Fisheries Science Research Institute | Tehran, Iran
    In:  http://aquaticcommons.org/id/eprint/25580 | 18721 | 2018-10-07 10:35:48 | 25580 | Iranian Fisheries Science Research Institute
    Publication Date: 2021-07-16
    Description: By-products consist of more than half of the total weight of fish. Most part of these wastes made from connective tissue proteins that provide good potential to produce gelatin. Nowadays, consumers are more health conscious and have responded to the call for a diet that contains low calorie and low fat. This work involved the characterization of a low-fat spread made of fish gelatin as gelling agent, emulsifier and fat replacer. Six treatments with Fish gelatin (FG) to pectin ratio 1:1 and 2:1, with pectin concentration of 1, 2 and 3%, were produced and evaluated for quality changes and storage-life at refrigerated storage. The results showed that prepared emulsions were physically stable and no phase separation observed during 8 wks. The pH of treatments was 4.5 to 4.9. The moisture content of treatments varied from 68.9% for T1 (FG/pectin ratio 1:1) to 65.4% for T6 (FG/pectin ratio 6:3). The Max. lipid of samples was measured 28.4%. Max. and min. protein of samples were 3.8% for T6 and 1.6% for T2 (FG/pectin ratio 2:1), respectively. No significant differences (p≥0.05) were observed between ash content of all treatments and control (commercial margarin). The acidity of treatments increased during storage and were significantly different from production day (p≤0.05). Peroxide value (PV) of treatments increased significantly at refrigerated storage. No significant differences were observed between PV of treatments during different wks of sampling. The results of texture profile analysis showed that firmness, compressibility and adhesiveness properties were significantly increase with higher substitution of FG with pectin. Color, Aroma, Taste and texture properties of prepared samples were found to significantly lower than control, according to sensory evaluation. Significant increases were observed in mold/yeast and psychrophilic count of treatments during storage. The macroscopic growth of molds was observed on all samples in 8th wks. No coliform growth was observed in all treatments at any time. Results suggest that low-fat spread properties were significantly influenced by different ratios of fish gelatin and pectin incorporated. It seems that these results can provide new opportunities to develop market with introducing novel products to response consumer demands. Some quality defects observed in this study can be improved by using suitable machinery at industrial scale.
    Keywords: Biology ; Chemistry ; Iran ; Fish gelatin ; Low-fat spread ; Fish wastes ; Quality characterictics ; Texture profile ; Shelf-life ; Refrigerated temperature ; Cultured Carp ; Diet ; Lipid
    Repository Name: AquaDocs
    Type: monograph
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  • 13
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    Freshwater Biological Association | Ambleside, UK
    In:  http://aquaticcommons.org/id/eprint/5157 | 3949 | 2011-09-29 15:19:58 | 5157 | Freshwater Biological Association
    Publication Date: 2021-07-08
    Description: The area studied was the River Frome system below Dorchester. The main river has its origins mainly in chalk springs, although some of its tributaries have surface run-off from farm lands and heath-lands. Thus the chemistry of the river is affected by changes in land practice and differences in the geology of the catchment area. Regular chemical analysis of chalk waters started at the River Laboratory in 1964, Regular weekly analyses have been carried out since 1965 at Bere Stream (a small chalk stream) and the River Frome (a large chalk stream); also single samples have been analysed to provide preliminary information. In 1970-71 an attempt was made to discover the contribution each main source made to the flow and chemical composition of the River Frome. Results of these investigations are presented in the paper.
    Keywords: Chemistry ; Environment ; Chemical analysis ; Chemical composition ; Rivers ; Stream flow ; Annual report ; England ; Dorset
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  • 14
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    Freshwater Biological Association | Ambleside, UK
    In:  http://aquaticcommons.org/id/eprint/5171 | 3949 | 2011-09-29 15:18:48 | 5171 | Freshwater Biological Association
    Publication Date: 2021-07-08
    Description: An explanation of the basic premises of the subject and its terminology is given. The article then outlines aspects of research on the organic material found in lacustrine sediments, and the analytical methods involved.
    Keywords: Chemistry ; Earth Sciences ; Diagenesis ; Freshwater lakes ; Geochemistry ; Lipids ; Sediment analysis ; Annual report
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    Freshwater Biological Association | Ambleside, UK
    In:  http://aquaticcommons.org/id/eprint/5225 | 1256 | 2011-09-29 15:12:36 | 5225 | Freshwater Biological Association
    Publication Date: 2021-07-09
    Description: The overall goal of the joint research project is to relate the chemical reactions involved in the formation of organo-aluminium complexes under acid conditions to their toxic effects on the physiology of aquatic organisms. Finally, this research is intended to predict toxic effects arising from acidity and aluminium under varying environmental conditions. This interim report examines the chemical modelling of ion-binding by humic substances where a computer model has been developed and is being tested using field data, and conditions required for the precipitation of aluminium in surface waters.
    Keywords: Chemistry ; Limnology ; Pollution ; Modelling ; Models ; Humic acids ; Surface water ; Aluminium compounds ; Aluminium ; Ions ; Toxicity ; England ; Duddon River
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    Type: monograph
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    Format: application/pdf
    Format: 26
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    Freshwater Biological Association | Ambleside, UK
    In:  http://aquaticcommons.org/id/eprint/5239 | 3949 | 2011-09-29 15:13:47 | 5239 | Freshwater Biological Association
    Publication Date: 2021-06-24
    Description: This review discusses the processes involved in the decomposition of organic carbon derived initially from structural components of algae and other primary producers. It describes how groups of bacteria interact in time and space in a eutrophic lake. The relative importance of anaerobic and aerobic processes are discussed. The bulk of decomposition occurs within the sediment. The role of bacteria in the nitrogen cycle and the iron cycle, and in sulphate reduction and methanogenesis as the terminal metabolism of organic carbon are described.
    Keywords: Biology ; Chemistry ; Anaerobic bacteria ; Bacteria ; Biodegradation ; Carbon cycle ; Eutrophic lakes ; Fresh water ; Geochemical cycle ; Iron ; Manganese ; Nitrates ; Nitrogen cycle ; Organic carbon ; Oxygen consumption ; Partical size ; Sedimentation ; Sulphates ; Sulphur ; Annual report
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    Freshwater Biological Association | Ambleside, UK
    In:  http://aquaticcommons.org/id/eprint/5247 | 3949 | 2011-09-29 15:08:19 | 5247 | Freshwater Biological Association
    Publication Date: 2021-07-09
    Description: The dace, Leuciscus leuciscus (L.) is an important cyprinid in terms of population biomass in chalk streams of southern England. Dace recruitment has been shown to vary widely from year to year and it is thought that this variation is largely as a result of the influence of abiotic factors, chiefly water temperature. From 1968 to 1981 there was a thirteen-fold difference in the year class structure index between the minimum index (0.25 in 1972) and the maximum (3.21 in 1976). The problems of such variation, especially those that could ensue from a succession of poor year-classes, are offset by the spread of reproductive effort by each female over several years.
    Keywords: Biology ; Chemistry ; Fisheries ; Abiotic factors ; Age composition ; Annual variations ; Climate ; Fecundity ; Fish eggs ; Fish larvae ; Freshwater fish ; Life history ; Mortality ; Population dynamics ; Predation ; Recruitment ; Sexual reproduction ; Survivial ; Water temperature ; Cyprinidae ; Leuciscus leuciscus ; England ; Dorset ; Chalk streams ; Annual report
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    Freshwater Biological Association | Ambleside, UK
    In:  http://aquaticcommons.org/id/eprint/5257 | 1256 | 2011-09-29 15:09:23 | 5257 | Freshwater Biological Association
    Publication Date: 2021-07-09
    Description: Phosalone is a non systematic, wide spectrum organophosphate pesticide which was discovered in 1961 in the laboratories of the Societe des Usines Chimique Rhone-Poulenc in France. It has been approved for commercial use since 1964 in France, in Australia since 1966, in the United Kingdom in 1967 and in many other countries including Japan, Egypt, USSR and the USA. This study provides a full literature review on all aspects of phosalone including its physical, biological and chemical characteristics, and analytical methods of analysis with particular reference to soils/sediments. Furthermore, it aims to develop a method for the determintion of phosalone in aquatic sediments and to determine the adsorption of phosalone onto kaolinite.
    Keywords: Chemistry ; Limnology ; Pollution ; Insecticides ; Metabolism ; Toxicity ; Biodegradation ; Adsorption
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    Type: monograph
    Format: application/pdf
    Format: application/pdf
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    Freshwater Biological Association | Ambleside, UK
    In:  http://aquaticcommons.org/id/eprint/5278 | 1256 | 2011-09-29 15:11:09 | 5278 | Freshwater Biological Association
    Publication Date: 2021-07-09
    Description: A literature survey was carried out into the effects of petroleum hydrocarbons in freshwater, from the toxicity, biodegradability and concentration aspects. It was supplemented by a selective search on hydrocarbons in the marine environment for comparison. The aim was to determine the major inputs of these hydrocarbons, their accumulation, effects and fate in freshwaters. The search was confined to the period 1965-1978. The bibliography contains 390 references, divided by subject.
    Keywords: Chemistry ; Limnology ; Pollution ; literature reviews ; petroleum ; toxicity ; biodegradation
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    Type: book , FALSE
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    Format: application/pdf
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  • 20
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    Freshwater Biological Association | Ambleside, UK
    In:  http://aquaticcommons.org/id/eprint/5349 | 1256 | 2011-05-13 11:55:43 | 5349 | Freshwater Biological Association
    Publication Date: 2021-07-10
    Description: This dataset provides raw data of chemical analyses made during studies on seasonal variations of some major ions in the stream water of the River Duddon in Cumbria. Measurements of sodium, calcium, potassium, magnesium and chloride ions and pH were taken at 5 stations in the River Duddon between January 1970 and August 1974.
    Description: This data was used in the publication: Carrick, T.R. & Sutcliffe, D.W.: Concentrations of Major Ions in Streams on Catchments of the River Duddon (1971-1974) and Windermere (1975-1978), English Lake District. Freshwater Biological Association, Ambleside, UK, 1983 (FBA Occasional Publications 22)
    Keywords: Chemistry ; Limnology ; Calcium ; chlorides ; fresh water ; ions ; magnesium ; potassium ; seasonal variations ; sodium ; water analysis ; dataset
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    Type: other
    Format: text/html
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  • 21
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    Freshwater Biological Association | Ambleside, UK
    In:  http://aquaticcommons.org/id/eprint/5351 | 1256 | 2011-05-13 11:55:21 | 5351 | Freshwater Biological Association
    Publication Date: 2021-07-10
    Description: This dataset provides raw data of chemical analyses made during studies on seasonal variations of some major ions in the stream water of the catchment of Lake Windermere in Cumbria. Measurements of sodium, calcium, potassium, magnesium, chloride ions and pH were taken at 37 stations in the catchment between 1975 and 1978.
    Description: This data was used in the publication: Carrick, T.R. & Sutcliffe, D.W.: Concentrations of major ions in streams on catchments of the River Duddon (1971-1974) and Windermere (1975-1978), English Lake District. Freshwater Biological Association, Ambleside, UK, 1983 (FBA Occasional Publications 22)
    Keywords: Chemistry ; Limnology ; Calcium ; chlorides ; fresh water ; ions ; magnesium ; potassium ; seasonal variations ; sodium ; water analysis ; England ; Lake Windermere ; dataset
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    Type: other
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  • 22
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    Freshwater Biological Association | Ambleside, UK
    In:  http://aquaticcommons.org/id/eprint/5354 | 1256 | 2011-09-16 12:01:28 | 5354 | Freshwater Biological Association
    Publication Date: 2021-07-10
    Description: This dataset provides raw data of chemical analyses made during studies on seasonal variations of 182 tarns in the English Lake District, Cumbria. Measurements of sodium, calcium, potassium, magnesium, pH, chloride ions, alkalinity, sulphite, strong acids and nitrate were taken between 1953 and 1978.
    Description: This data was used in the publication: Carrick, T.R. & Sutcliffe, D.W.: Concentrations of major ions in lakes and tarns on the English Lake District (1953-1978). Freshwater Biological Association, Ambleside, UK, 1982 (FBA Occasional Publications 16)
    Keywords: Chemistry ; Limnology ; Calcium ; chlorides ; fresh water ; ions ; magnesium ; potassium ; seasonal variations ; sodium ; water analysis ; alkalinity ; England ; Lake District ; dataset
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  • 23
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    Freshwater Biological Association | Ambleside, UK
    In:  http://aquaticcommons.org/id/eprint/5352 | 1256 | 2012-07-04 19:32:47 | 5352 | Freshwater Biological Association
    Publication Date: 2021-07-10
    Description: This dataset provides raw data of chemical analyses made during studies on seasonal variations of treated sewage effluent from Grasmere Treatment Unit in Cumbria. Measurements of sodium, calcium, potassium, magnesium and chloride ions were taken between 1974 and 1976.
    Description: This data was used in the publication: Carrick, T.R. & Sutcliffe, D.W.: Concentrations of major ions in streams on catchments of the River Duddon (1971-1974) and Windermere (1975-1978), English Lake District. Freshwater Biological Association, Ambleside, UK, 1983 (FBA Occasional Publications 22)
    Keywords: Chemistry ; Limnology ; Calcium ; chlorides ; fresh water ; ions ; magnesium ; potassium ; seasonal variations ; sodium ; water analysis ; England ; Grasmere ; dataset
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    Freshwater Biological Association | Ambleside, UK
    In:  http://aquaticcommons.org/id/eprint/5350 | 1256 | 2011-05-13 11:56:03 | 5350 | Freshwater Biological Association
    Publication Date: 2021-07-10
    Description: This dataset provides raw data of chemical analyses made during studies on seasonal variations of some major ions in the stream water of the upper basin of the River Duddon in Cumbria. Measurements of sodium, calcium, potassium, magnesium and chloride ions and pH were taken at 26 stations in the River Duddon basin between 1972 and 1974.
    Description: This data was used in the publication: Carrick, T.R. & Sutcliffe, D.W.: Concentrations of Major Ions in Streams on Catchments of the River Duddon (1971-1974) and Windermere (1975-1978), English Lake District. Freshwater Biological Association, Ambleside, UK, 1983 (FBA Occasional Publications 22)
    Keywords: Chemistry ; Limnology ; Calcium ; chlorides ; fresh water ; ions ; magnesium ; potassium ; seasonal variations ; sodium ; water analysis ; England ; River Duddon ; dataset
    Repository Name: AquaDocs
    Type: other
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  • 25
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    Freshwater Biological Association | Ambleside, UK
    In:  http://aquaticcommons.org/id/eprint/5353 | 1256 | 2012-07-04 19:33:33 | 5353 | Freshwater Biological Association
    Publication Date: 2021-07-10
    Description: This dataset provides raw data of chemical analyses made during studies on seasonal variations of 25 frequently sampled tarns in Cumbria. Measurements of sodium, calcium, potassium, magnesium, pH, chloride ions, alkalinity, sulphite, strong acids and nitrate were taken between 1954 and 1956 and between 1974-1976.
    Description: This data was used in the publication: Carrick, T.R. & Sutcliffe, D.W.: Concentrations of major ions in streams on catchments of the River Duddon (1971-1974) and Windermere (1975-1978), English Lake District. Freshwater Biological Association, Ambleside, UK, 1983 (FBA Occasional Publications 22)
    Keywords: Chemistry ; Limnology ; Calcium ; chlorides ; fresh water ; ions ; magnesium ; potassium ; seasonal variations ; sodium ; water analysis ; alkalinity ; England ; Lake District ; dataset
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    Type: other
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    Freshwater Biological Association | Ambleside, UK
    In:  http://aquaticcommons.org/id/eprint/5111 | 3949 | 2011-09-29 15:23:22 | 5111 | Freshwater Biological Association
    Publication Date: 2021-07-08
    Description: An article discussing changes observed in phytoplankton of the Lake District. An overview is given of previous phytoplankton studies undertaken in the area, detailing some changes found in various waterbodies. Water quality changes in Lake Windermere are mentioned, including the gradual increase of dissolved organic matter (DOM), believed to be caused by the increase of sewage to the lake. The lakes in the Alps are given as an example of a similar anthropogenic pollution scenario. The treatment of a Lake District tarn with bone meal is described. The article goes on to discuss the composition of plankton throughout the year under a variety of climatic conditions. A figure shows seasonal variation in the consistuents of phytoplankton in Windermere (north basin).
    Keywords: Biology ; Chemistry ; Limnology ; Phytoplankton ; Limnology ; Dissolved organic matter ; Seasonal variations ; Sewage ; Water quality ; Annual reports ; England ; Lake District
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    Type: book_section , FALSE
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    Freshwater Biological Association | Ambleside, UK
    In:  http://aquaticcommons.org/id/eprint/5107 | 3949 | 2011-09-29 15:23:50 | 5107 | Freshwater Biological Association
    Publication Date: 2021-07-08
    Description: A progress report on research undertaken on the chemical budget of a lake, outlining the importance of nitrogen and phosphorus in governing the production of life in freshwater. The report uses the Rivers Brathay and Leven, which flow into Windermere, as examples. The report also refers to the Rivers Rothay, Troutbeck and Cunsey. A table is including which shows the monthly average nitrate content (mg per litre) of the River Brathey and River Leven for 1937 into 1938. The report also includes a figure showing Windermere lake levels, discharge and rainfall during 1937. It also briefly considers possible anthropogenic influences on water quality.
    Keywords: Chemistry ; Ecology ; Limnology ; Phosphorus ; Organic compounds ; Sewage ; Diatoms ; Algae ; Sediment chemistry ; Seasonal variations ; Annual reports ; Nitrates ; River discharge ; England
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    Format: application/pdf
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    Freshwater Biological Association | Ambleside, UK
    In:  http://aquaticcommons.org/id/eprint/5114 | 3949 | 2011-09-29 15:21:32 | 5114 | Freshwater Biological Association
    Publication Date: 2021-07-08
    Description: An article looking at the numerical distribution of bacteria in lakes, the types most commonly present and the nitrogen-cycle, in Lake Windermere. The methodology is explained, including the sampling frequency and depths, and bacteria culturing techniques. Water bodies other than Lake Windermere were also sampled and these are detailed, including a water reservoir. A summary of the work into horizontal of bacteria is given, including a table showing the number of bacteria per millilitre at different distances from inflow into Windermere. A summary of the work into vertical distribution is also given, including two figures, one showing seasonal variation during 1938-9 in numbers of bacteria at different depths in Winderemere, and the other showing the relationship between the numbers of bacteria at 10 metres depth in Windermere and the rainfull during the previous 7 days. A summary of the types of bacteria found, as well as work on the nitrogen cycle in Esthwaite Water, Lake Windermere and Blelham Tarn are given.
    Keywords: Biology ; Chemistry ; Limnology ; Nitrogen cycle ; Bacteria ; Freshwater ecology ; Limnology ; Seasonal variations ; Water column ; Water reservoirs ; Annual reports ; England ; Lake District
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    Freshwater Biological Association | Ambleside, UK
    In:  http://aquaticcommons.org/id/eprint/5112 | 3949 | 2011-09-29 15:23:20 | 5112 | Freshwater Biological Association
    Publication Date: 2021-07-08
    Description: An article reviewing the work undertaken looking at the seasonal variation of chemical conditions in water at various depths in lakes. The laboratory tests undertaken for the research is outlined, as well as details of the sampling locations and the staff involved with the work. One figure shows the seasonal variation in the amounts of dissolved substances in the surface water of Windermere during 1936. Another figure shows seasonal varation inthe dry weight of phyto- and zooplankton in Windermere. Seasonal changes are discussed further and a table is included showing chemical conditions in winter and summer for Windermere.
    Keywords: Biology ; Chemistry ; Limnology ; Limnology ; Chemistry ; Seasonal variations ; Diatoms ; Phytoplankton ; Zooplankton ; Water column ; Surface water ; Annual reports ; England ; Lake District
    Repository Name: AquaDocs
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    Freshwater Biological Association | Ambleside, UK
    In:  http://aquaticcommons.org/id/eprint/5122 | 3949 | 2011-09-29 15:22:47 | 5122 | Freshwater Biological Association
    Publication Date: 2021-07-08
    Description: An article reviewing the methods of biological surveillance of chalk-streams developed and commonly used at that time, with a focus on their application to the River Frome catchment in Dorset. In evaluating the surveillance methods, the author looks at sampling methods (including cores and kick-sampling), the level of identification of macroinvertebrates, and temporal and spatial variations. Responses of indices to organic pollution are also discussed. A number of accompanying figures are also included.
    Keywords: Biology ; Chemistry ; Ecology ; Environment ; Chalk ; Water management ; Cores ; Aquatic communities ; Freshwater ecology ; Invertebrate larvae ; Biological surveys ; Temporal variations ; Spatial variations ; Annual reports ; England
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    Freshwater Biological Association | Ambleside, UK
    In:  http://aquaticcommons.org/id/eprint/5123 | 3949 | 2011-09-29 15:22:51 | 5123 | Freshwater Biological Association
    Publication Date: 2021-07-08
    Description: A review article detailing the background, development and functionality of the Windermere Profiler, a multi parameter environmental monitoring instrument for use in lakes, reservoirs and rivers. The article explains the requirement for regular data collection by the Freshwater Biological Association at Windermere. The article covers the requirements of a profiling instrument, the design considerations, the electronic circuitry, the computer program, the operation of the computer software, the profiler in use and further developments to the design. A number of figures and images accompany the article.
    Keywords: Chemistry ; Environment ; Limnology ; Profilers ; Inland water environment ; Water reservoirs ; Lakes ; Rivers ; Temperature data ; Electrical conductivity ; Dissolved oxygen ; Depth measurement ; Light attenuation ; Annual reports ; England ; Lake District
    Repository Name: AquaDocs
    Type: book_section , FALSE
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    Format: application/pdf
    Format: 93-106
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    Freshwater Biological Association | Ambleside, UK
    In:  http://aquaticcommons.org/id/eprint/5117 | 3949 | 2011-09-29 15:22:21 | 5117 | Freshwater Biological Association
    Publication Date: 2021-07-08
    Description: An article discussing the factors affecting the rate of growth of brown trout, detailing the research udnertaken at Wray Castle, designed to clarify the influencing factors in different waters and investigate what would be required to increase their size. The article considers factors such as alkalinity, total hardness, the presence of coarse fish in the waterbodies and competition for food. Previous work undertaken on brown trout in Ireland by other authors is reviewed. A figure showing average growth rate of brown trout in five lakes, as determined from their scales (Lough Derg, Windermere, Loch Leven, Ullswater, Haweswater).
    Keywords: Biology ; Chemistry ; Limnology ; Coarse fish ; pH effects ; Water hardness ; Food availability ; Limnology ; England ; Lake District
    Repository Name: AquaDocs
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    Freshwater Biological Association | Ambleside, UK
    In:  http://aquaticcommons.org/id/eprint/5189 | 3949 | 2011-09-29 15:16:49 | 5189 | Freshwater Biological Association
    Publication Date: 2021-07-09
    Description: There is no evidence of an increase in the acidity (lower pH or alkalinity) of water-bodies in the Lake District over the last 50 years. Brown trout occur in acid streams and upland tarns where pH is 4.5-5.2 throughout the year. Their occurrence in such waters in Britain and Ireland has been known for most of this century and there is no previous evidence of harmful effects on salmonid fisheries, though numbers of fish are naturally low. However, many benthic invertebrates that are common in hill-streams where pH is above 5.7 do not occur in more acid streams. This phenomenon occurs in the headwaters of several western rivers in Cumbria. It is not a recent response to "acid rain". Harmful effects of pH are undoubtedly more pronounced in waters that are poor in other dissolved ions. Low concentrations of sodium, potassium, calcium and chloride are especially important and may limit the distributions of some aquatic animals even where pH is above 5.7. The concentration of sulphate ions is usually relatively high but this is not important to the fauna; concentrations are at least two times higher in productive alkaline water-bodies than they are in unproductive acid waters.
    Keywords: Chemistry ; Ecology ; Limnology ; Acid rain ; Acidification ; Alkalinity ; Freshwater pollution ; pH ; Pollution effects ; Invertebrata ; Salmonidae ; England ; Lake District ; Annual report
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    Freshwater Biological Association | Ambleside, UK
    In:  http://aquaticcommons.org/id/eprint/5181 | 3949 | 2011-09-29 15:17:17 | 5181 | Freshwater Biological Association
    Publication Date: 2021-07-09
    Description: The chemical speciation of both metals and non-metals, the use of polarographic techniques, and application to the study of the chemistry of anoxic waters are considered. In the first part of the paper unfamiliar terminology is explained and then an example of simple lake chemistry is presented to illustrate why the concept of speciation is necessary.
    Keywords: Chemistry ; Limnology ; Chemical speciation ; Anoxic basins ; Annual report
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    Freshwater Biological Association | Ambleside, UK
    In:  http://aquaticcommons.org/id/eprint/5195 | 3949 | 2011-09-29 15:15:06 | 5195 | Freshwater Biological Association
    Publication Date: 2021-07-09
    Description: This review is concerned with the kinetics of calcium carbonate formation and related processes which are important in many hard waters.
    Keywords: Chemistry ; Calcite ; Calcium carbonates ; Chemical precipitation ; Fresh water ; Geochemical cycle ; Annual report
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    Freshwater Biological Association | Ambleside, UK
    In:  http://aquaticcommons.org/id/eprint/5193 | 3949 | 2011-09-29 15:15:03 | 5193 | Freshwater Biological Association
    Publication Date: 2021-07-09
    Description: A study of the geochemical cycling of iron and manganese in a seasonally stratified lake, Esthwaite water is described. This work is based on speculative ideas on environmental redox chemistry of iron which were proposed by C.H. Mortimer in the 1940's. These observations have been verified and some speculations confirmed, along with a new understanding of the manganese cycle, and detailed information on the particulate forms of both iron and manganese. Details on the mechanisms and transformations of iron have also emerged.
    Keywords: Biology ; Chemistry ; Chemical precipitation ; Freshwater lakes ; Iron ; Manganese ; Oxidation ; Redox potential ; Reduction ; Stratification ; England ; Esthwaite Lake ; Annual report
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    Freshwater Biological Association | Ambleside, UK
    In:  http://aquaticcommons.org/id/eprint/5197 | 3949 | 2011-09-29 15:15:33 | 5197 | Freshwater Biological Association
    Publication Date: 2021-07-09
    Description: Studies by the Freshwater Biological Association over the last 25 years have supplied data relevant to the levels of acidity in local soils and water before the onset of industrial pollution and current interest in acid rain. This article reviews published analysis from cores of lake sediments, in or near the catchment of the River Duddon. Electron spin resonance spectra of humic acids and iodine values confirm evidence from pollen analysis for a history of progressive acidification of the source material of lake sediments since before 5000 radiocarbon years, in upland catchments of the Lake District. Processes involved included: removal of basic ions from soils by rainfall, the effects of which were intensified by removal by man of deciduous forest; acidification of soils and waters by decomposition products of Calluna and further acidification of waters by Sphagnum species which colonized habitats where drainage became impeded by paludification processes.
    Keywords: Biology ; Chemistry ; Earth Sciences ; Acid rain ; Acidification ; Freshwater lakes ; Lake Basins ; Lake deposits ; pH ; Palnology ; England ; Cumbria ; Annual report
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  • 38
    Publication Date: 2021-05-19
    Description: 0Genetic polymorphism by means of biochemical genetic markers using polyacrylamide gel electrophoresis system in four barbus fish species has been investigated. Species scientific name were Barbus sharpeyi ; Gunther, 1847 , Barbus grypus ; Heckel, 1843, Barbus xanthopterus ; Heckel, 1843 and Barbus esocinus ; Heckel, 1843.Sampling site and location were mainly in the rivers located in Khoozestan province such as Karoon and Karkheh rivers and the Dez dam. Different organs such as blood, muscle, kidney, eye and heart were sampled and analysed for the presence of tf, es, sod and pgm alleles. High polymorphism and presence of different alleles scored, but populations were not in the H-W equilibrium. Considring results, using current and avaiable genetic markers such as microsattelits is recommended for future works.
    Description: Iranian Fisheries Science Research Institute
    Description: Published
    Keywords: Chemistry ; Genetics ; Genetics Markers ; Distinguish ; Barbus ; Species ; Barbus sharpeyi ; Barbus xanthopterus ; Barbus esocinus
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    Type: Report , Refereed
    Format: 62pp.
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  • 39
    Publication Date: 2021-05-19
    Description: Cheshmehkileh River and adjacent mountainous streams, play a strategic role as a historical axis for anthropogenic civilization, human welfare also habitat and migration pathway of commercial – biologic valuable fishes e.g. Caspian trout, Caspian kuttum, members of Cyprinidae family in south Caspian Sea drainage. Treats such as overfishing of Caspian trout and Red spotted trout stocks in mountainous headwaters, barriers construction and manipulations those are out of river carrying capacity developed by human activities, affected normal function of river as well. Sand mining big factories establishment next to the river, legal and illegal trade of river sediments, direct entry of Tonekabon landfill leakage into the river, development of Rainbow trout farms since 3 decades and huge effluents into the river containing dead fish and types of solids, escapement of cultured Rainbow trouts into the river, … are major minimum factors which needs basic information for integrating inclusively drainage management system. Cheshmehkileh River contains Headwaters of Dohezar (Daryasar & Nusha), Sehezar and Valamroud rivers during 13 monthly sampling phases between September 2009 and October 2010 based on macrozoobenthoses investigations by EPT, EPT/C EPA protocols, measurements of nominated physic-chemical and microbiologic parameters. Probability of Rainbow trouts escapement and invasion, existence, nutrition in Cheshmehkileh environment indeed investigated. Data analysis explained significant differences (P〈0.05) between groups of measured parameters in different sampling stations. Dendogram of clustered analysis based on consolidation of major biologic/ physic-chemical and microbiologic parameters, separated stations No. 1, 3, 2, 4 in one group and remained classified in different groups. Station 8 and 9 similarly separated which expressed general similarities according to Sehezar river environment which were differs in comparison with other stations. Station 11 separated according to its natural quality of water and environment. Similarities between station 10 to Sehezar river stations 8 and 9 expressed general influence of Sehezar River more than Dohezar River in Cheshmehkileh condition especially in station No. 10. High scores of EPT and EPT/C indices in upstream stations 1, 3 and 8 also low score of indices in stations 7, 13 and 6 expressed levels of environment quality between these groups of stations. Maximum average biomass of macroinvertebrates belongs to Trichoptera order in Cheshmehkileh River. Significant decrease of biomass in stations 11, 12 and 13 in comparison with other stations stated environment degradation in mentioned stations relevant to excessive sand mining as well. Pollution resistant groups of invertebrates significantly increased in downstreams against upstream stations. Also disappearing of Plecoptera order in station No. 7, 9, 10 and 13 stated low quality of environment in comparison with upstream stations. Confirmation of effects quality and quantity for point and non-point sources of imported pollutants require specific management considerations in order to present exploitations, pollutants control and emergencies for river monitoring in forthcoming years.
    Description: Iranian Fisheries Science Research Institute
    Description: Published
    Keywords: River ; Pollution ; Aquaculture ; EPTC ; Assessment ; Macroinvertebrates ; Chemistry ; Microbiology
    Repository Name: AquaDocs
    Type: Report , Refereed
    Format: 138pp.
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  • 40
    ISSN: 1434-193X
    Keywords: Triplet recombination ; Electron transfer ; Radical ions ; Photochemistry ; Terpenes ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: ---The triphenypyrylium tetrafluoroborate (TPT)-sensitized reactions of several terpene donor molecules, including sabinene (1), α-phellandrene (4), α-terpinene (5) and γ-terpinene (6) give rise to significantly different products than reactions induced by other electron-transfer sensitizers, such as 1,4-dicyanobenzene (DCB). The divergent reactions require decidedly different key intermediates; the products obtained with TPT can be explained by dissociative recombination of the intermediate radical-radical cation pair in the triplet state, generating donor-derived biradicals.
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  • 41
    ISSN: 1434-193X
    Keywords: Azides ; Cleavage reactions ; Cycloadditions ; Nitrogen heterocycles ; Polycycles ; Ring expansion ; Synthetic methods ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: ---2-Alkyl-1-methylquinazolinium hexafluorophosphates 9 are deprotonated by sodium or potassium hydride to afford solutions of 2-alkylidenedihydroquinazolines 10, which were investigated by NMR spectroscopy. Trapping with methanesulfonyl azide (5a) of 10 in situ or subsequent treatment with trifluoromethanesulfonyl azide (5b) gives mixtures of colourless (15) and intensely yellow N-sulfonylimino-1,4-benzodiazepines 16 along with products due to cleavage of the exocyclic double bond of 10, viz. 11 and 13. The ethylidene compound 10b yields the bicyclic products 18 and 19, apparently by complex sequences of reactions that are triggered by removal of the acidic proton at C-2 of 16b and 16f. The structures of the products are based on spectroscopic evidence and X-ray diffraction analyses performed on 15b, 16d, 16e, and 19.
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  • 42
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 2000 (2000), S. 1589-1593 
    ISSN: 1434-193X
    Keywords: Azaallenium ions ; Azaallylium ions ; Iminium ion ; Kinetics ; Linear Free Energy Relationships ; Ab initio calculations ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: ---The rate constants for the reactions of the 2-azaallenium ion 1b+, the 2-azaallylium ion 2a+ and the iminium ion 3+ with different nucleophiles were determined by 1H NMR spectroscopy. By correlation with the Linear Free Enthalpy Relationship (LFER) lg k20°C = s (E + N), developed by Mayr and Patz, the electrophilicity parameters E(1b+) = -3.7, E(2a+) ≍ -16 and E(3+) = -10.43 were obtained. They show that the relative reactivities of these ions are approximately 1012:1:106. Quantum chemical calculations (ab initio, DFT) of the methyl anion affinities for the ions 1b+,2a+ and3+ are in agreement with the experimental E values. The X-ray structure of 3+·CF3SO3- is reported for the first time; it shows no strong interaction between the cation and the anion.
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  • 43
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 2000 (2000), S. 1595-1601 
    ISSN: 1434-193X
    Keywords: Oxazoline N-oxide ; Cycloadditions ; Cycloadditions ; Lactams ; Thienamycin ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: ---[3+2] Cycloaddition between a camphor-derived oxazoline N-oxide 9 and the γ,δ-unsaturated enamino ester 11 afforded the single adduct 6. A stereoselective reduction of the enamino ester side chain allowed the control of the absolute configuration of the two additional asymmetric centres. Nitrogen protection and oxidative hydrolysis of the resulting product 13, followed by further functional group manipulations, led to the β-lactam derivative 1, a known precursor of the β-methylthienamycin derivative2a.
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  • 44
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 2000 (2000), S. 1603-1607 
    ISSN: 1434-193X
    Keywords: Boron ; Cyclotrimerizations ; Nitrogen heterocycles ; Macrocycles ; Subphthalocyanines ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: ---The regioselective preparation of ortho-substituted subphthalocyanides was achieved employing 3-substituted phthalonitrile derivatives as starting materials. A mechanistic proposal has been outlined.Supporting information for this article is available on the WWW under //http://www.wiley-vch.de/contents/jc_2046/2000/99525_s.pdf or from the author.
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  • 45
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 2000 (2000), S. 1609-1615 
    ISSN: 1434-193X
    Keywords: Terpenoids ; Natural products ; Total synthesis ; Cyclizations ; Rearrangements ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: ---A new route for the synthesis of 2,7- and 7-functionalized labdanes starts from (R)-carvone (1). 11-Nordrim-7-en-9-one (15) is an appropriate starting material for the total synthesis of hispanone (21), a biologically active furolabdane isolated from the Mediterranean medicinal plant Ballota saxatilis.
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  • 46
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 2000 (2000), S. 1623-1626 
    ISSN: 1434-193X
    Keywords: Iridoid glucoside ; (8S)-Kingiside ; (8S)-Loganin ; (8S)-7-Ketologanin ; Asymmetric synthesis ; Natural products ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: ---The tetraacetyl derivative 8 of the naturally occurring kingiside (8a) was prepared from aucubin (1). Intermediates in the synthesis were (8S)-tetraacetyl loganin (6) and (8S)-tetraacetyl-7-ketologanin (7), whose free (8R)-epimers occur in many different plants (Caprifoliaceae, Loganiaceae). The 13C NMR spectrum allows the structure to be unequivocally identified.
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  • 47
    ISSN: 1434-193X
    Keywords: Tetrakis(dimethylamino)naphthalenes ; Basicity ; Hydrogen bonds ; Cyclicvoltammetry ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: ---For comparison to the recently described 2,3,6,7-tetrakis(dimethylamino)naphthalene (1) the three isomers 2,3, and 4 were synthesized. The basicities of this group of isomers are strongly dependent upon the different mutual orientations of the pairs of dimethylamino substituents: only the isomers 3 and, partially, 4, both with dimethylamino groups in adjacent peri-positions of the naphthalene, are strong “proton sponges”. For the isomers 1 and 2 with the same number and kind of twofold dimethylamino substituents in neighbouring ortho-positions, however, no significant basicity increase is observed. To explain this difference between the two groups of isomers it is suggested that in the ortho-pairs of 1 and 2 the C-N bonds diverge considerably, leading to an increased N···N distance and consequently to less stable [N···H···N]+ hydrogen bonds in contrast to the parallel C-N bonds in the peri-substituted isomers 3 and 4. X-ray crystal structure analyses of the bases and of some of the salts derived therefrom were solved and are discussed. Cyclic voltammetry indicates that 1 to 4 are strong electron donors, reacting easily to radical cations or dications which with suitable acids have been obtained as salts.
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  • 48
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 2000 (2000), S. 1677-1683 
    ISSN: 1434-193X
    Keywords: Radicals ; Cyclizations ; Pyridinethione ; Tetrahydrofurans ; Asymmetric synthesis ; Thiazolethione ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: ---The trisubstituted functionalized tetrahydrofurans 10, 11, 16, 18, and 19 were photochemically prepared from 2,3-syn- and 2,3-anti-configuredN-(3-benzoyloxy-5-hexen-2-oxy)thiazole-2(3H)-thione anti-6, pyridinethiones 7, anti-8, and BrCCl3. The formation of tetrahydrofurans was achieved by an efficient and highly regioselective alkoxyl radical cyclization (5-exo-trig). The 2,3-anti substituted intermediates 9 and 12 cyclize stereoselectively whereas a 2,3-syn-configured O-radical affords both possible diastereomeric addition products in equal amounts. The cyclized tetrahydrofuryl methyl radicals were trapped with the bromine atom donor BrCCl3 to afford the bromomethyl-substituted cyclic ethers 10, 11, 18, and 19 in excellent yields. The utility of this reaction was stressed by conversion of one of the newly prepared tetrahydrofurans in a two-step synthesis into (+)-allo-muscarine (+)-20.Supporting information for this article is available on the WWW under //http://www.wiley-vch.de/contents/jc_2046/2000/99590_s.pdf or from the author.
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  • 49
    ISSN: 1434-193X
    Keywords: Thioketones ; Thiocarbonyl ylides ; Cycloadditions ; Cycloreversions ; Sulfur heterocycles ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: ---Reactions of diaryl thioketones with diazomethane at room temperature afford 4,4,5,5-tetraaryl-1,3-dithiolanes; the scope of this surprising 2:1 interaction has been studied for decades (Schönberg Reaction). The clue to the mechanism was our observation that the stoichiometry is 1:1 at -78 °C, and 2,5-dihydro-2,2-diaryl-1,3,4-thiadiazoles are formed as primary [2+3] cycloadducts. They lose N2 at -45 °C in first-order reactions generating diaryl thioketone S-methylides which can be intercepted by thioketones (→1,3-dithiolanes), multiple CC bonds, or acids HX. In the absence of trapping reagents, the elusive intermediates either dimerize furnishing 2,2,3,3-tetraaryl-1,4-dithianes or give rise to 2,2-diarylthiiranes by electrocyclization. Beyond thiobenzophenone and diazomethane, our main model reaction, the studies involve fluorene-9-thione, 4,4-dimethoxy- and 4,4-dichlorothiobenzophenone. The ring of 2,5-dihydro-2,2-diphenyl-1,3,4-thiadiazole (8) is opened by LDA at -78 °C and derivatives of anion 12 are obtained. - In summa: The Schönberg reaction consists of two 1,3-dipolar cycloadditions, linked by a 1,3-dipolar cycloreversion.
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  • 50
    ISSN: 1434-193X
    Keywords: Conjugation ; Boron ; Sensors ; Cyclic voltammetry ; Polymers ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: ---New electropolymerizable aromatic compounds (i.e. pyrrole, thiophene, aniline) bearing boronic acid and ester substituents have been synthesized and their electrochemical behavior has been investigated. Functionalized polythiophene and polypyrrole films could be anodically generated in acetonitrile, whereas the polyaniline derivative was electroformed in an acidic aqueous solution. The electrochemical responses of some of these materials were changed when fluoride ions were added to the electrolytic solutions. The strongest modifications, caused by binding of fluoride by the immobilized boron, were observed for the polypyrrole derivative in hydroorganic media.
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  • 51
    ISSN: 1434-193X
    Keywords: Heterocycles ; Zinc ; Palladium ; Catalysts ; Sulfur ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: ---Organozinc halides derived from Grignard reagents behave differently in their reaction with ethyl (±±)-(2RS,3SR)-tetrahydro-4-methylene-2-phenyl-3-(phenylsulfonyl)furan-3-carboxylate (3) according to the hybridisation of the carbon ligand. During the development of short multi-component reactions for the synthesis of diverse functionalized ethyl 2,5-dihydrofuran-3-carboxylates it was discovered that aryl and vinyl zinc halides undergo clean reaction with 3 in the presence of Pd(PPh3)4. In contrast, when alkyl zinc halides are reacted with 3 in the presence of Pd(PPh3)4, reductive desulfonation of 3 is observed. Remarkably, in the absence of a transition metal catalyst, the allylic substitution of 3 with alkyl zinc halides proceeds cleanly and in moderate to good yield.
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  • 52
    ISSN: 1434-193X
    Keywords: Self-assembly ; Vapor-pressure osmometry ; Resorcin[4]arenes ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: ---Resorcin[4]arene tetracarboxylic acids 5,6 (A) and resorcin[4]arene tetrapyridines 2,3 (P) self-assemble in chloroform solution to form stable heterotopic AP dimers. Data from NMR titration and dilution experiments, as well as from vapor-pressure osmometry (VPO), indicate that the AP dimer is formed with an association constant greater than 107 M-1. Solid-solution extraction experiments are indicative of the formation of a 2:1 trimer (A2P), while self-associated homotopic species (A2 and A3) can be detected by NMR and VPO. Analysis of the heterotopic noncovalent assembly process over a range of compositions shows that these other species are much less stable than the AP heterodimer, which is the exclusive species at an A/P concentration ratio of 1:1 (〉 99.7% of the total at 10 mM).
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  • 53
    ISSN: 1434-193X
    Keywords: Sulfoxides ; β-Amino sulfones ; Mannich type reaction ; Lithium perchlorate ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: ---The LiClO4-mediated one-pot reaction of aldehydes with (trimethylsilyl)dialkyl amines and the lithium salt of sulfoxides or sulfones, affords the corresponding β-(dialkylamino) sulfoxides and β-(dialkylamino) sulfones in high yields. The aminosulfoxidation reaction of aliphatic or aromatic aldehydes lacks diastereoselectivity, but the diastereomeric sulfoxides can be separated by HPLC or column chromatography for further use.
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  • 54
    Electronic Resource
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    Weinheim : Wiley-Blackwell
    Liebigs Annalen 2000 (2000), S. 1741-1744 
    ISSN: 1434-193X
    Keywords: Bridged pyranose derivatives ; Ring enlargement ; Carbenes ; Glycosides ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: ---Addition of dichlorocarbene to the glycal (±±)-2 followed by cyclopropyl-allyl rearrangement leads to the chloro-2H-pyran (±±)-4. Oxidation of (±±)-4 and reduction of the obtained hydroxypyranone (±±)-5 gave the methyl pyranoside (±±)-6. The relative configuration of (±±)-6 was established by X-ray structural analysis of the corresponding acetate (±±)-7. The synthesis of the optically active starting materials (+)-2 and (-)-2 is also reported.
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  • 55
    Electronic Resource
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    Weinheim : Wiley-Blackwell
    Liebigs Annalen 2000 (2000), S. 1745-1758 
    ISSN: 1434-193X
    Keywords: CMP-Neu5Ac analogues ; Enzyme inhibitors ; Substrate analogues ; Transition state analogues ; Transferases ; Carbohydrates ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: ---Quinic acid was transformed into phosphitamides 16, 25, and 36, which could be readily linked to 5′-O-unprotected cytidine derivative 17. Ensuing oxidation of the obtained phosphite triesters with tBuO2H and hydrogenolytic de-O-benzylation furnished the corresponding phosphate diesters 18, 26, and 38. Base catalyzed removal of acetyl protecting groups, and methyl ester hydrolysis furnished CMP-Neu5Ac analogues 1d, 1e, and 2. Quinic acid was also transformed into 1,2-unsaturated diallyl α-hydroxymethyl-phosphate derivatives (R)- and (S)-46, which on reaction with cytidine phosphitamide 47 afforded the phosphite triesters. Subsequent oxidation with tBuO2H and then treatment with NEt3 gave phosphate diester derivatives (R)- and (S)-48. Deallylation, acetyl group removal, and methyl ester hydrolysis furnished (R)- and (S)-3, respectively. Treatment of (R)- and (S)-48 with DBU as a base led to acetic acid elimination, thus yielding, after de-O-allylation, acetyl group cleavage, and ester hydrolysis, diene derivative (E)-4. Donor substrate analogues 1d and 1e exhibited good α(2-6)-sialyltransferase inhibition (Ki: 2.0·10-4 and 2.0·10-5 M). However, transition state analogues (R)-, and particularly (S)-3 showed excellent inhibition properties (Ki: 1.6·10-6 and 2.7·10-7 M).
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  • 56
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    Weinheim : Wiley-Blackwell
    Liebigs Annalen 2000 (2000), S. 1759-1765 
    ISSN: 1434-193X
    Keywords: Cyclitols ; Aminocyclitols ; Glycosidase inhibitors ; α-Mannosidase inhibitors ; Deoxygenation ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: ---Three deoxy derivatives 2-4 of the α-mannosidase inhibitor mannostatin A (1) were synthesized, and their inhibition of Jack bean α-mannosidase was evaluated in order to elucidate the roles of each of the three hydroxyl groups of the inhibitor. The 1- and 2-deoxy derivatives 2 and 3 retained some inhibitory activity, although reduced by a factor of about 100 relative to the parent, whereas it was completely lost with the 3-deoxy derivative 4. Structure and activity relationships are discussed in the light of these findings.
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  • 57
    Electronic Resource
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    Weinheim : Wiley-Blackwell
    Liebigs Annalen 2000 (2000), S. 1767-1772 
    ISSN: 1434-193X
    Keywords: Circular dichroism ; Conformation analysis ; s-Triazines ; Chiral auxiliaries ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: ---CD data of the optically pure 2-[(R)-1-(9-anthryl)ethylamino]-4-chloro-6-[(R)-1-(1-naphthyl)ethylamino]-1,3,5-triazine, 2[(R)-1-(9-anthryl)ethylamino]-4,6-bis[(R)-1-(1-naphthyl)ethylamino]-1,3,5-triazine, 2,4-bis[(R)-1-(9-anthryl)ethylamino]-6-chloro-1,3,5-triazine are presented. The analysis of the CD spectra by means of the nonempirical DeVoe approach has afforded the complete conformational characterisation of the three s-triazine derivatives, allowing us to establish how the conformation of these derivatives depends on the nature of the substituent 1-arylethylamino groups.
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  • 58
    ISSN: 1434-193X
    Keywords: Cycloadditions ; Carbenes ; Nitrones ; Nitrilimines ; Pyrazolines ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: ---The reaction of tert-butylalkynyl chromium Fischer carbene complex 1 with nitrones 2 affords β-enamino-ketoaldehydes 4 by the light-promoted rearrangement of the corresponding [3+2] cycloadduct carbene complexes 3. On the other hand, [3+2] cycloaddition of chiral nonracemic Fischer alkenyl carbene complexes 19 with nitrilimines 10 yields enantiomerically pure Δ2-pyrazolines with high regio- and diastereoselectivity.
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  • 59
    ISSN: 1434-193X
    Keywords: Asymmetric synthesis ; Zinc ; Transition structures ; QM/MM computations ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: ---Trimethylsilyl substitutions of the fenchyl alcohols [(1R,2R,4S)-exo-(2-Ar)-1,3,3-trimethylbicyclo[2.2.1]heptan-2-ol, Ar = 2-methoxyphenyl (1) and Ar = 2-(dimethylaminomethyl)phenyl (2)] yield the chiral ligands 3 [Ar = 2-methoxy-3-(trimethylsilyl)phenyl] and 4 [Ar = 2-(dimethylaminomethyl)3-(trimethylsilyl)phenyl]. Increased reactivities and enantioselectivities in diethylzinc additions to benzaldehyde are obtained from 3 (63% ee R) and 4 (93% ee S), relative to 1 (26% ee S) and 2 (73% ee S). X-ray crystal structures of 3 and of its methylzinc complex 3-Zn reveal out-of-plane bending of the methoxy groups as major geometrical consequences of the trimethylsilyl substitutions. Analyses of QM/MM ONIOM μ-O transition-structure models for 1, 2, 3, and 4 show that trimethylsilyl-induced distortions of methoxy and of dimethylaminomethyl groups explain the observed increased enantioselectivities.
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  • 60
    ISSN: 1434-193X
    Keywords: Palladium ; exo-π-Allylpalladium complexes ; Allylic alkylation ; Spiro compounds ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: ---The palladium(0)-catalyzed alkylation of 2,3-bis(acetoxymethyl)bicyclo[2.2.1]hepta-2,5-diene 1 with malonate-type enolates as nucleophiles is investigated. A monoalkylated product is formed first, and undergoes (depending on the nucleophile used) a second intramolecular reaction leading to spirocyclopropane-annulated bicyclo[2.2.1]heptene derivatives 5. The formation of endo spirobicyclic cyclopropanes adducts as major isomer is rationalized by assuming formation of an intermediate exo-(π-allyl)palladium complex.
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  • 61
    ISSN: 1434-193X
    Keywords: Ketones ; Reductions ; Micelles ; Cobalt ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: ---Operationally simple and environmentally benign procedures have been developed to selectively reduce different α,β-unsaturated ketones, 4,4-dimethylcyclohex-2-ene-1-one (1), isophorone (2), benzylideneacetone (3), chalcone (4) by NaBH4 or by the system NaBH4 + CoCl2. Alternative reaction media to the extensively used MeOH have been explored, and new procedures take advantage of the acceleration and chemoselectivity induced by water or by aqueous micellar solutions. It was possible to selectively and quantitatively afford pure products of 1,2 and of 1,4 reduction as well as the totally reduced compounds (yield and selectivity 〉 90%) by simple changes in the experimental conditions.
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  • 62
    ISSN: 1434-193X
    Keywords: C-Glycosides ; Conformation analysis ; Molecular dynamics ; Selectins ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: ---The conformational behavior of the C-glycosyl analogue of sialyl-α-(2→3)-galactose, synthesized as a glycosidase inhibitor, has been studied using a combination of NMR spectroscopy (J and NOE data) and molecular dynamics calculations. The obtained results show that the population distribution of conformers with respect to the orientation about the pseudo-glycosidic linkages is mainly controlled by steric interactions. This is in contrast to findings made for O-glycosides. In these natural compounds, the conformational behavior about the glycosidic linkage Φ is mainly governed by the exo-anomeric effect.
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  • 63
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    Liebigs Annalen 2000 (2000), S. 1815-1820 
    ISSN: 1434-193X
    Keywords: Asymmetric synthesis ; Palladium-catalysed couplings ; Palladacycles ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: ---Chiral C2-symmetric N-benzylazetidines have been conveniently prepared from optically pure anti-1,3-diols without loss of enantiomeric purity. N-Debenzylation led to the corresponding N-unsubstituted azetidines, which were then subjected to palladium-catalysed coupling reactions with aryl bromides to afford chiral N-arylazetidines. (R,R)-N-Benzyl-2,4-dimethylazetidine has been employed in the synthesis of a new cyclopalladated complex, which can be used, for instance, as a chiral recognition agent for phosphorus ligands.
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  • 64
    ISSN: 1434-193X
    Keywords: Cyclizations ; Spiro compounds ; Nucleosides ; Isomerizations ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: ---Syntheses of the spiro nucleosides 2′-deoxyhydantocidin 3a and its 1′-epimer 3b are described. The newly developed route involves a Horner-Wadsworth-Emmons condensation of the phosphonate 16 with the erythrose derivative 15 affording a mixture of six isomers which was fully assigned by NMR spectroscopy. The mixture was directly converted into the final compounds in an efficient base-catalyzed cyclization reaction. A base-catalyzed interconversion between the two isomers was observed.
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  • 65
    ISSN: 1434-193X
    Keywords: Benzodiazepines ; Heterocycles ; Azeto[1,2-a]-1,5-benzodiazepines ; Cyclizations ; Cycloadditions ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: ---The reaction of o-phenylenediamine (4) with one, two or three equivalents of p-substituted 3-dimethylaminopropiophenone hydrochlorides 5a-e was studied. 4-Aryl-2,3-dihydro-1H-1,5-benzodiazepine derivatives 6a-e were obtained in good yields, along with the 1:2-adducts 7c-e and the unexpected 1:3-adducts rac-8c-e. The type of adduct formed is determined by the molar ratio of the reactants 4 and 5 and by the nature of the substituent in the para position of the propiophenone 5.
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  • 66
    ISSN: 1434-193X
    Keywords: Cup-shaped PAHs ; Host-guest compounds ; Host-guest chemistry ; Cyclizations ; Semiempirical calculations ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: ---Cyclotrimerisation of benzo-polycyclic bromostannylalkenes 8a-d with Cu(NO3)2·3H2O in THF affords benzotri(benzonorbornadienes) 3a-d as a mixture of the syn and anti isomers. The ratio of syn to anti is close to the 1:3 statistical value in most cases (i.e. in cyclotrimers 3a,b,d), but highly in favour of the anti isomer in 3c, where steric hindrance by the methoxy groups plays an important role in the stereochemistry of the cyclotrimerisation. The substrates for the cyclotrimerisation, i.e. the bromostannyl alkenes 8a-d, were prepared from bromoalkenes 7a-d by treatment with base (LDA) and quenching with trimethyltin chloride. In turn, bromoalkenes 7a-d were prepared from alkenes 5a-d by radical bromination-elimination. The reaction conditions used were designed to minimise Wagner-Meerwein rearrangements that would lead to unwanted bromo isomers. The cup-shaped syn cyclotrimers 3a-d exhibit high electron density within the cavity as determined by AM1 semiempirical calculations of their electrostatic potential surfaces and are valuable substrates for supramolecular chemistry. As an example, it is shown that fullerene C60 is drawn into solution in acetonitrile by complexation with both the syn and anti trimer of benzonorbornadiene 3a.
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  • 67
    ISSN: 0935-6304
    Keywords: Capillary HPLC ; gradient elution ; temperature programming ; phenolic compounds ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: ---This paper describes a liquid chromatographic method using a reversed phase capillary column coupled to an UV detector for the quantitation of thirteen pollutant phenols. Chromatographic separation was carried out with gradient elution at 25.0 ± 0.1°C. The two major anisocratic elution modes (gradient elution and temperature programming) were evaluated. The detection limit range was 10-81 pg (100 nL injected). The chromatographic method combined with liquid-liquid extraction was applied to analysis of these compounds in river water. Recoveries of 75-103% were achieved for most of them.
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  • 68
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    Journal of High Resolution Chromatography 23 (2000), S. 389-392 
    ISSN: 0935-6304
    Keywords: Capillary SFC ; zinc dialkyldithiophosphates ; lubricating oils ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: No abstract
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  • 69
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    Journal of High Resolution Chromatography 23 (2000), S. 393-396 
    ISSN: 0935-6304
    Keywords: Supercritical fluid chromatography (SFC) ; micropacked capillary columns ; waxes ; restoring ; objects of art ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: No abstract
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  • 70
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    Journal of High Resolution Chromatography 23 (2000), S. 379-385 
    ISSN: 0935-6304
    Keywords: Aroma ; “lulo del Chocó” ; Solanum topiro ; volatiles ; glycosidically bound volatiles ; glycoside TFA derivatives ; enantioselective gas chromatography ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: ---The volatile constituents of lulo del Chocó (Solanum topiro) fruit pulp obtained by liquid-liquid extraction were analyzed by capillary GC and capillary GC-MS. In total, 30 components were identified with methyl salicylate, hexadecanoic acid, hexanal, guaiacol, ethyl butanoate, and ethyl acetate being the major components. Chirospecific MDGC analysis revealed the predominance of (R)-ethyl-3-hydroxybutanoate (ee 40%) and the presence of racemic mixtures both of δ-octalactone and of δ-decalactone. For γ-hexalactone, γ-octalactone, and γ-decalactone enantiomeric distributions of 22.4 : 77.6, 22.9 : 77.1, and 20.0 : 80.0, (R) : (S), respectively, were determined. Glycosidically bound aroma compounds were identified by capillary GC and capillary GC-MS after isolation of the glycosidic fraction obtained by Amberlite XAD-2 adsorption and methanol elution followed by hydrolysis with a commercial pectinase enzyme. In total 13 bound aroma compounds (aglycones) were identified. These aglycones mainly consisted of compounds exhibiting aromatic structures. Additionally, with the aid of capillary GC and capillary GC-MS (EI and NCI) of trifluoroacetylated derivatives we identified eight glucosides: the novel 3,6-epoxy-7-megastigmen-5,9-diol β-D-glucopyranoside and the hexyl, benzyl, linalyl oxide (furanic), 2-phenylethyl, vomifolyl (isomer 1), (6S,9R)-vomifolyl, and scopoletin β-D-glucopyranosides.
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  • 71
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    Journal of High Resolution Chromatography 23 (2000), S. 409-412 
    ISSN: 0935-6304
    Keywords: Cyclodextrin ; capillary electrophoresis ; system peak ; CHES 1 ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Using a running buffer containing cyclodextrins (CDs) and 2-[N-cyclohexylamino]-ethanesulfonic acid (CHES), positive system peaks were observed in the analysis of a ganglioside mixture by CE-UV. These system peaks were related to CDs in the running buffer because these peaks were also detected when a plug of solution devoid of CDs but having the same CHES concentration and pH as the running buffer was injected. Neutral CDs were separated owing to the formation of inclusion complexes with the anionic CHES ion. One possible explanation for the positive system peaks is that the anionic CD-CHES inclusion complex is displaced by co-ions with higher UV absorptivity.
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  • 72
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    Journal of High Resolution Chromatography 23 (2000), S. 565-566 
    ISSN: 0935-6304
    Keywords: Liquid chromatography ; zinc dithiocarbamate ; vulcanization accelerator ; rubber gloves ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: No abstract
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  • 73
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    Journal of High Resolution Chromatography 23 (2000), S. 603-608 
    ISSN: 0935-6304
    Keywords: Solvation parameter model ; ystem constants for poly(dimethyldiphenylsiloxane) HP-5 and poly(ethylene glycol) HP-INNOWax stationary phases ; temperature ; molecular interaction ; retention models ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: ---No abstract
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  • 74
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    Journal of High Resolution Chromatography 23 (2000), S. 561-564 
    ISSN: 0935-6304
    Keywords: Retention factors ; Cinnamomi ramulus ; high-performance liquid chromatography ; capillary electrophoresis ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: ---No abstract
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  • 75
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    Journal of High Resolution Chromatography 23 (2000), S. 590-594 
    ISSN: 0935-6304
    Keywords: Ion chromatography ; graphitic carbon stationary phases ; anions ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: ---Inorganic anions could be separated on porous graphitic carbon stationary phases in ion chromatography. Ion exchange between eluent anions and sample anions on the stationary phase was confirmed by the retention behavior and the possibility of indirect photometric detection. The elution order of anions was different from that observed for commercially available anion exchangers. Chloride, nitrate, and sulfate contained in tap water could be determined in 7 min.
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  • 76
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    Journal of High Resolution Chromatography 23 (2000), S. 485-488 
    ISSN: 0935-6304
    Keywords: Pyrethroids ; solid-phase microextraction ; water analysis ; temperature ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: ---Synthetic pyrethroids are increasingly being used for insect control on field crops because of their advantageous environmental properties such as short field life, broad spectrum of insecticide activity, and relatively low mammalian toxicity. In the present work, experimental conditions were optimized for trace analysis of pyrethroids in water by using solid-phase microextraction followed by capillary gas chromatography. Effects of temperature, SPME-fiber diameter, and matrix were studied. SPME used off-line with a gas chromatograph electron-capture detection (GC-ECD) showed a linear response over a wide concentration range. Our results showed a strong temperature effect on pyrethroid extraction yield. The detection limit after 5 min of SPME-fiber exposure to the samples changed from 1 ppb (at 30°C) to 0.1 ppt (at 90°C), which is a 10000 increase in pyrethroid detection. The standard deviations of the analyte peak area ratios were typically in the range of 1-7% at 30°C and of 3 to 15% at 90°C. Best conditions for pyrethroids analysis were achieved using high temperature solution and a 100 μm polydimethylsiloxane fiber. No matrix (river water) influence was observed on detection of the investigated pyrethroids.
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  • 77
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    Journal of High Resolution Chromatography 23 (2000), S. 19-26 
    ISSN: 0935-6304
    Keywords: Microfabrication ; monolith ; electrochromatography ; peptides ; reactive ion etching ; reversed phase ; nanocolumns ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Monolith columns are generally fabricated by polymerization of monomers within a column. This paper reviews an alternative strategy in which the bed is microfabricated in an inorganic material by ablation. Channels of 1.5 μm width and 10 μm depth were sculpted in quartz by deep reaction ion etching. Using this approach chromatographic beds were constructed in which cubic support structures were created and arranged in rows to mimic particles in a conventional column. Beds ranging from hundreds of thousands to millions of “particles” with volumes of 15 nL to 15 μL were produced. Columns that had been derivatized with an octadecyl silane stationary phase were used to separate both low molecular weight analytes and peptides in the CEC mode. Plate height in the CEC mode was 1.2 μm at maximum efficiency.
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  • 78
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    Journal of High Resolution Chromatography 23 (2000), S. 39-43 
    ISSN: 0935-6304
    Keywords: Monoliths ; CIM® monolithic column ; dynamic binding capacity ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The characterization of CIM® DEAE monolithic columns in terms of dynamic binding capacity is presented in this paper. Breakthrough experiments were performed for capacity determination. Bovine serum albumin (BSA) was used as a model protein. It is shown that CIM® monolithic columns have good batch-to-batch reproducibility as well as long-term stability. The experiments performed under different linear velocities demonstrated that the dynamic capacity is unaffected at least up to a linear velocity of 2450 cm/h. Furthermore, the breakthrough curve slope is constant, indicating that the capacity would remain constant at even higher linear velocities. The adsorption isotherm of BSA dissolved in 20 mM Tris-HCl buffer shows a constant capacity of around 30 mg/mL of support down to a concentration of 20 μg/mL. The capacity is substantially influenced by the ionic strength; however, 20% of the maximal capacity is still preserved at 0.3 M NaCl.
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  • 79
    ISSN: 0935-6304
    Keywords: Monolith ; factor VIII ; affinity chromatography ; combinatorial peptide library ; peptide synthesis ; recombinant proteins ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: FVIII is a very complex molecule of great therapeutic significance. It is purified by a sequence of chromatographic steps including immunoaffinity chromatography. A peptide affinity chromatography method has been developed using peptides derived from a combinatorial library. Spot technology using cellulose sheets has been applied for this purpose. The dual positional scanning strategy was used for identification of the amino acids in random positions. Approximately 5000 possible candidates found in the first screening round were reduced to a panel of 36. Six candidates have been selected empirically. Five peptides seem to be directed against the light chain of FVIII, one peptide seems to be directed against the heavy chain. The peptides have been immobilized on conventional beaded material and CIM polymethacrylate monoliths. Much better performance with respect to capacity and selectivity has been observed with the monolithic material. Exposure of the ligand and its ensuing accessibility are responsible for these properties.
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  • 80
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    Journal of High Resolution Chromatography 23 (2000), S. 67-72 
    ISSN: 0935-6304
    Keywords: Capillary electrochromatography ; monolithic column ; electroosmotic flow ; retention mechanism ; aromatic compound ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A new kind of monolithic capillary electrochromatography column with poly(styrene-co-divinylbenzene-co-methacrylic acid) as the stationary phase has been developed. The stationary phase was found to be porous by scanning electron microscopy and the composition of the continuous bed was proved by IR spectroscopy to be the ternary polymer of styrene, divinylbenzene, and methacrylic acid. The effects of operating parameters, such as voltage, electrolyte, and organic modifier concentration in the mobile phase on electroosmotic flow were studied systematically. The retention mechanism of neutral solutes on such a column proved to be similar to that of reversed-phase high performance liquid chromatography. In addition, fast analyses of phenols, chlorobenzenes, anilines, isomeric compounds of phenylenediamine and alkylbenzenes within 4.5 min were achieved.
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  • 81
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    Journal of High Resolution Chromatography 23 (2000), S. 73-80 
    ISSN: 0935-6304
    Keywords: Continuous-bed ; sol-gel ; octadecylsilica ; mixed-mode stationary phase ; large-pore ; column technology ; capillary electrochromatography ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: ---Sol-gel bonded packing materials in continuous-bed columns have been prepared for capillary electrochromatography (CEC). Three packing materials were investigated: small-pore Spherisorb ODS1 (3 μm, 80 Å) with octadecyl as stationary phase, small-pore mixed-mode Spherisorb ODS/SCX (3 μm, 80 Å) with octadecyl and propyl sulfonic acid as stationary phases, and large-pore Nucleosil ODS (7 μm, 1 400 Å) with octadecyl as stationary phase. The characteristics of these columns were compared in terms of electroosmotic flow, efficiency, inertness, and retention factors. In contrast to columns containing sol-gel bonded ODS, columns containing sol-gel bonded mixed-mode ODS/SCX generated nearly pH independent electroosmotic flow (EOF) over pH 2-9. Columns containing sol-gel bonded large-pore ODS produced nearly three times lower reduced plate height than those containing small-pore ODS. Efficiencies of 220,000 plates per meter and 175,000 plates per meter were obtained from columns containing sol-gel bonded 7 μm, 1 400 Å ODS and columns containing sol-gel bonded 3 μm, 80 Å ODS, respectively, which are among the highest reported efficiencies for continuous-bed columns. In CEC, over one million plates per meter and pH independent EOF are expected from continuous-bed columns containing sol-gel bonded 1.5 μm particles with large pores and mixed-mode stationary phases.
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  • 82
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    Journal of High Resolution Chromatography 23 (2000), S. 81-88 
    ISSN: 0935-6304
    Keywords: Monolithic chromatography columns ; capillary electrochromatography (CEC) ; micro high performance liquid chromatography ; sol-gel based columns for chromatography ; fritless capillary chromatography columns ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: ---Particle-loaded (3 μm, octadecylsilica) monolithic sol-gel columns have been prepared and selected characteristics measured. Several electrical properties may be calculated from simple current measurements in the column as a whole. Resistivity in the packed segment is approximately three times that in open segments, resulting in a 60% increase in field strength in the packed regions compared to the capillary with no packing. The surprisingly high specific permeability of these sol-gel columns is characteristic of 8-μm particles, which allows their operation in the microLC mode at pressures as low as 69 kPa where their efficiency is about 50,000 plates per meter and in the CEC mode where efficiency is about 106,000 plates per meter at 5 kV. There is a relatively rapid loss of efficiency with increasing linear velocity beyond 0.2 mm/s in microLC mode, which may be due to additional diffusion processes in the inter-particulate voids. A rapid loss of efficiency above 0.5 mm/s is also observed in the CEC mode, for the same reasons. Chromatographic retention behavior in either separation mode is characteristic of conventional octadecylsilica particles, indicating that analytes have significant access to the surface within the pores of the immobilized bonded phase.
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  • 83
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    Journal of High Resolution Chromatography 23 (2000), S. 89-92 
    ISSN: 0935-6304
    Keywords: Capillary electrochromatography ; packed columns ; fritless columns ; stationary phases ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: ---Fritless packed silica gel columns were prepared using sol-gel technology. A part of a 75 μm i.d. fused silica capillary was filled with a mixture of tetramethoxysilane and poly(ethylene glycol). After gelling at 40°C and heating at 300°C, the resultant silica gel was derivatized with dimethyloctadecylchlorosilane. A scanning electron micrograph of a cross-section of the capillary column showed that the gel took the form of a spherical particle aggregate and adhered to the column inner wall. The column performance was evaluated for electrochromatography using acetonitrile-50 mM HEPES buffer (pH 6.6) (60/40 or 40/60, v/v) as the mobile phase. An electroosmotic flow of 1.0 mm/s was generated with (60/40, v/v) acetonitrile/HEPES buffer at a field strength of 546 V/cm. Using a sol-gel-derived packed column at an electroosmotic flow of 0.5 mm/s, efficiencies of up to 1.1×105 plates/m were obtained for retained solutes.
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  • 84
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    Journal of High Resolution Chromatography 23 (2000), S. 93-99 
    ISSN: 0935-6304
    Keywords: HPLC ; monolithic column ; silica rod column ; fast separations ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: ---The application of a new silica-based, monolithic-type HPLC-column for fast separations is presented. The column is prepared according to a new sol-gel process, which is based on the hydrolysis and polycondensation of alkoxysilanes in the presence of water soluble polymers. The method leads to “rods” made of a single piece of porous silica with a defined pore structure, i. e. macro- and mesopores. The main feature of silica rod columns is a higher total porosity, about 15% higher than of conventional particulate HPLC columns. The resulting column pressure drop is therefore much lower, allowing operation at higher flow rates including flow gradients. Consequently, HPLC analysis can be performed much faster, as it is demonstrated by various applications.
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  • 85
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    Journal of High Resolution Chromatography 23 (2000), S. 3-18 
    ISSN: 0935-6304
    Keywords: Capillary electrochromatography ; monolithic columns ; synthetic polymers ; stationary phase ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Monolithic materials have quickly become a well-established stationary phase format in the field of capillary electrochromatography (CEC). Both the simplicity of their in situ preparation method and the large variety of readily available chemistries make the monolithic separation media an attractive alternative to capillary columns packed with particulate materials. This review summarizes the contributions of numerous groups working in this rapidly growing area, with a focus on monolithic capillary columns prepared from synthetic polymers. Various approaches employed for the preparation of the monoliths are detailed, and where available, the material properties of the resulting monolithic capillary columns are shown. Their chromatographic performance is demonstrated by numerous separations of different analyte mixtures in variety of modes. Although detailed studies of the effect of polymer properties on the analytical performance of monolithic capillaries remain scarce at this early stage of their development, this review also discusses some important relationships such as the effect of pore size on the separation performance in more detail.
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  • 86
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    Journal of High Resolution Chromatography 23 (2000), S. 100-105 
    ISSN: 0935-6304
    Keywords: Preparative chromatography ; silica monoliths ; PrepROD™ ; productivity ; SMB-chromatography ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: ---The use of monolithic silica sorbents for the isolation of substances by preparative liquid chromatography is demonstrated. Preparative liquid chromatography is recognized as a valuable technique for the isolation and purification of substances in the pharmaceutical and fine chemicals industry. The system technology has meanwhile reached a high standard, and the greatest future improvements are expected to arise from new and improved adsorbents. Monolithic silica sorbents offer some unique features for preparative liquid chromatography. They exhibit high efficiencies even at high flow rates due to their fast convective mass transfer and can therefore be used at very high mobile phase velocities, leading to high productivity and hence to maximum process economy. The benefits of this new type of adsorbent are illustrated for an example in batch-chromatographic mode and an example using the continuous simulated moving bed (SMB) technology.
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  • 87
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    Journal of High Resolution Chromatography 23 (2000), S. 106-110 
    ISSN: 0935-6304
    Keywords: Silica ; monolithic column ; aging ; mesopores ; pore size distribution ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: ---Mesopore formation in silica gels having continuous macropores has been investigated. The macroporous wet silica gel prepared by the sol-gel process including phase separation was aged in a basic solvent making use of hydrolysis of urea in a closed condition. The mesopore structure was finally obtained by subsequent evaporation drying of solvent and heat-treatment at 600°C for 2 h. The dissolution-reprecipitation kinetics at the interfaces between wet gel skeletons and an external solvent affected the size and volume of pores formed within the skeletons. Below 120°C, mesopores suitable for various chromatographic applications have been formed typically within 24 h. On the other hand, at 200°C, the pore size attained the macropore dimensions (〉50 nm), and the whole macroporous morphology was significantly modified.
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  • 88
    ISSN: 0935-6304
    Keywords: Monolithic column ; silica monolith ; HPLC ; capillary liquid chromatography ; capillary electrochromatography ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: ---Two types of monolithic silica columns derivatized to form an ODS phase, one prepared in a fused silica capillary (SR-FS) and the other prepared in a mold and clad with an engineering plastic (poly-ether-ether-ketone) (SR-PEEK), were evaluated. The column efficiency and pressure drop were compared with those of a column packed with 5-μm ODS-silica particles and of an ODS-silica monolith prepared in a mold and wrapped with PTFE tubing (SR-PTFE). SR-FS gave a lower pressure drop than a column packed with 5-μm particles by a factor of 20, and a plate height of 20 μm at a linear velocity below 1 mm/s. SR-PEEK showed higher flow-resistance than the other monolithic silica columns, but they still showed a minimum plate height of 8-10 μm and a lower pressure drop than popular commercial columns packed with 5-μm particles. The evaluation of SR-FS columns in a CEC mode showed much higher efficiency than in a pressure-driven mode.
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    Journal of High Resolution Chromatography 23 (2000), S. 119-126 
    ISSN: 0935-6304
    Keywords: Gas chromatography ; retention volume ; real gas carrier ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The problem of the calculation and interpretation of the net retention volume with a real gas as carrier is revisited. The properties of the carrier are described by a first order virial equation of state. The net retention volume of a solute is related to the mean flow rate of the carrier, therefore determination of the mean flow rate of a real gas carrier is reviewed. It is shown that the mean flow rate cannot be calculated from the mean column pressure. With a real gas carrier the local capacity factor depends on the local pressure of the real gas. The basic relationship between the net retention volume and the function describing this pressure dependence is also reviewed. Precise formulae as well as practical approximations are presented for the calculation of the mean flow rate, of the mean column pressure, and of a representative pressure related to the mean capacity factor.
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  • 90
    ISSN: 0935-6304
    Keywords: Chemiluminescence ; diol compound ; oxalate ; post-column reaction ; ruthenium complex ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: ---In this paper we propose a new post-column detection method for polyols containing 1,2-diol, 1,3-diol, and saccharides. The polyols are oxidized in a photochemical reactor to yield oxalate with subsequent chemiluminescence detection using [Ru(III)(bpy)3]3+. A mixing solution of eluate and oxidizing reagent is delivered to a reaction coil, which is then irradiated with ultraviolet light to promote the oxidation reaction. The detection limits for 1,2-ethanediol (ethylene glycol) and 1,3-propanediol were 38 pmol and 23 pmol, respectively.
    Additional Material: 5 Ill.
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  • 91
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    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 23 (2000), S. 131-137 
    ISSN: 0935-6304
    Keywords: On-line coupled LC-GC ; nitrogen selective detection ; NPD ; carbazoles ; PANH ; personal exposure measurement ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A coupled LC-GC method for the analysis of carbazole-type PANH has been developed and evaluated. Group separation and isolation of carbazoles from interfering acridines in a complex sample matrix was accomplished by using a back-flush technique and an in situ end-capped dimethylaminopropyl silica column in the HPLC part of the system. On-line injection of the carbazole fraction into the GC column was performed with a loop-type interface utilizing concurrent solvent evaporation technique. An LOD of 1-3 pg of individual carbazole compounds was achieved by nitrogen selective detection using an NPD. The method is shown to be robust and is demonstrated by application to personal exposure measurement in an aluminum reduction plant.
    Additional Material: 4 Ill.
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  • 92
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    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 23 (2000), S. 138-142 
    ISSN: 0935-6304
    Keywords: Capillary electrochromatography ; nucleosides ; short-end injection ; phenyl-bonded silica ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: ---The influence of several experimental parameters (pH, ionic strength, organic modifier content of hydro-organic buffer) upon EOF, migration time, and retention factor has been studied in CEC with a phenyl-bonded silica column on a model mixture of five nucleosides. This paper illustrates the current interest in CEC as a method of resolving complex mixtures of neutral and ionic solutes and demonstrates the potential of the short-end injection method as a means of reducing analysis time.
    Additional Material: 4 Ill.
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  • 93
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    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 23 (2000), S. 143-148 
    ISSN: 0935-6304
    Keywords: Analysis of anthraquinones ; capillary electrophoresis ; high-performance liquid chromatography ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: ---The separation and determination of twelve anthraquinones, viz. anthraquinone 1, chrysphanol 2, aloe-emodin 3, alizarin 4, anthraquinone-2-carboxylic acid 5, purpurin 6, sennoside B 7, sennoside A 8, emodin 9, quinalizarin 10, rhein 11, and anthraflavic acid 12, were achieved by capillary electrophoresis (CE) and high-performance liquid chromatography (HPLC). Detection at 260 nm with a buffer solution containing 30 mM sodium borate (adjusted to pH = 10.56 with 0.05N NaOH) and acetonitrile (9 : 1) in CE or with a linear gradient elution containing 20 mM KH2PO4 with 0.05% phosphoric acid (pH = 2.91) and methanol in HPLC was found to be the most suitable approach for this separation. Contents of six components (2, 3, 7, 8, 9, 11) in crude Rhei Rhizoma extract could easily be determined within 39 min by CE or 63 min by HPLC. The effects of buffers on this separation and the validation of the two methods were studied.
    Additional Material: 5 Ill.
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  • 94
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    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 23 (2000), S. 156-157 
    ISSN: 0935-6304
    Keywords: Capillary gas chromatography ; trichlorophenols ; ammonia ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: ---No abstract
    Additional Material: 1 Tab.
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  • 95
    Electronic Resource
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    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 23 (2000), S. 149-155 
    ISSN: 0935-6304
    Keywords: Capillary GC ; fast GC ; on-column injection ; narrow-bore column ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: ---In this work a fast gas chromatography set-up with on-column injection was optimized and evaluated with a model mixture of C8-C28 n-alkanes. Usual injection volumes when using narrow-bore (e. g., 0.1 mm i.d.) analytical columns are ca. 0.1 μL. The presented configuration allows introduction of 10-30-fold larger sample volumes without any distortion of peak shapes. In the set-up a normal-bore retention gap (1 m×0.32 mm i. d.) was coupled to a narrow-bore (4.8 m×0.1 mm i. d.×0.4 μm film thickness) analytical column using a low dead volume column connector. The effects of the experimental conditions such as inlet pressure, sample volume, initial injection temperature, and oven temperature on a peak focusing are discussed. H-u curves for helium and hydrogen are used to compare their suitability for high speed gas chromatography and to show the dependence of separation efficiency on the carrier gas velocity at high inlet pressures. In the fast gas chromatography system a baseline separation of C10-C28 n-alkanes was achieved in less than 3 minutes.
    Additional Material: 4 Ill.
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  • 96
    Electronic Resource
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    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 23 (2000), S. 182-188 
    ISSN: 0935-6304
    Keywords: Comprehensive two-dimensional gas chromatography ; GC×GC ; thermal modulation ; oil analysis ; petroleum analysis ; analysis of middle-distillate oil fractions ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: ---Comprehensive two-dimensional gas chromatography (GC×GC) is an utterly suitable separation technique for the analysis of complex samples, such as oil fractions. Once the two columns and the operating conditions are properly tuned, the technique is able to provide a detailed characterization of such materials. Some considerations applying to the tuning of a GC×GC system for a specific separation are presented and discussed. The authors present a number of different column sets and conditions which allow the separation of a non-aromatic hydrocarbon solvent, a kerosene, the light end of a crude oil, and an olefinic fraction, respectively. The highly structured GC×GC chromatograms, together with chemical knowledge about the samples, provide a much more comprehensive characterization of the samples than hitherto possible.
    Additional Material: 7 Ill.
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  • 97
    ISSN: 0935-6304
    Keywords: Comprehensive two-dimensional gas chromatography ; thermal desorption modulator ; temperature programming ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: ---In comprehensive two-dimensional gas chromatography, two individual separations are coupled by means of a rotating thermal desorption modulator interface. The injection pulse introduced via the interface onto the second column should be as short as possible. Parameters affecting the modulator operation are studied. In the set-up used in this study, the temperature of the second column can be programmed independently from that of the first column. Optimization of the second-dimension separation to minimize peak broadening and maximize resolution is discussed and an elegant approach to determine second-dimension retention times using a non-constant modulation frequency is demonstrated. The high separation power of the comprehensive system is demonstrated by the analysis of technical and biota samples containing chlorinated biphenyls and toxaphene.
    Additional Material: 7 Ill.
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  • 98
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    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 23 (2000), S. 197-201 
    ISSN: 0935-6304
    Keywords: Multidimensional gas chromatography ; comprehensive two-dimensional gas chromatography ; GC×GC ; oxygenates ; MTBE ; reformulated gasoline ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: ---Comprehensive two-dimensional gas chromatography (GC×GC) has been applied to the quantitation of oxygenates in reformulated gasoline. Target oxygenates were C1-C4 alcohols, tert-pentanol, methyl tert-butyl ether (MTBE), diisopropyl ether (DIPE), ethyl tert-butyl ether (ETBE), and tert-amyl methyl ether (TAME). These were separated from the gasoline matrix using a volatility-based selectivity in the first chromatographic dimension, followed by a mixed-phase polarity/shape selectivity in the second dimension. The high resolving power of this stationary phase combination completely separated all oxygenates except DIPE, ETBE, and TAME, which exhibited coelution with other nonpolar gasoline components. Oxygenates quantitation was achieved with the use of an internal standard, an FID detector, and calibration curves. Quantitation results are in good agreement with ASTM and EPA standard methods. When coupled with our previous method for BTEX and aromatics, a single GC×GC method can now quantitate MTBE, alcohols, BTEX, and aromatics in a one-hour analysis.
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  • 99
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    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 23 (2000), S. 474-478 
    ISSN: 0935-6304
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: ---Solid-phase extraction, on-line derivatization, and measurement by ion trap mass spectrometry (ITD-MS) were used to investigate the biological degradation of pharmaceutical residues (clofibric acid, ibuprofen, diclofenac). The results of the single steps of sample pretreatment and analytical determination are reported. MS/MS measurements were performed on an ITD-MS by selecting collision induced dissociation of the molecular ions (M+) as parent ions to defined daughter ions. A pilot sewage plant and biofilm reactors operating under oxic and anoxic conditions were run as model systems with synthetic sewage water containing 10 to 50 mg/L dissolved organic carbon (DOC) and pharmaceuticals in concentrations of 10 μg/L. Clofibric acid displayed its persistent character in all cases. The pilot sewage plant and the oxic biofilm reactor showed comparable results for diclofenac and ibuprofen, which both were partly degraded. These results can explain the occurrence of these substances in sewage effluents and in the aquatic environment. A high degree of degradation was found especially for ibuprofen in the oxic biofilm reactor, which was attributed to adaptation of the biofilm to the residue. Two metabolites of ibuprofen could be identified on the basis of their mass spectra and comparison with literature data, viz. hydroxyibuprofen and carboxyibuprofen.
    Additional Material: 8 Ill.
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  • 100
    ISSN: 0935-6304
    Keywords: Silicone oil ; supercritical fluid chromatography (SFC) ; micropacked columns ; MALDI-TOF ; GC/MS ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: ---No abstract
    Additional Material: 4 Ill.
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