ALBERT

All Library Books, journals and Electronic Records Telegrafenberg

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
Filter
  • Lepidoptera  (475)
  • Column liquid chromatography  (377)
  • Immunocytochemistry  (357)
  • Chemical Engineering
  • Inorganic Chemistry
  • LUNAR AND PLANETARY EXPLORATION
  • Physics
  • Springer  (1,210)
  • 1985-1989  (882)
  • 1980-1984  (323)
  • 1970-1974  (5)
  • 1955-1959
Collection
Keywords
Years
Year
  • 101
    ISSN: 1573-1561
    Keywords: Corn earworm ; Heliothis zea ; Lepidoptera ; Noctuidae ; pheromone ; (Z)-11-hexadecen-1-ol ; laboratory rearing
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract Analysis of ovipositor extracts of lab-reared (〉 120 generations) and wildHeliothis zea indicated small but significant differences in the percent composition of the four aldehyde components of the sex pheromone. (Z)-11-hexadecen-1-ol (Z11–16∶OH) was present in both populations and amounted to only 2.8% of the total pheromone. There was no significant difference in four of the six behavioral categories between lab-reared and wild males exposed to the four-component sex pheromone in the flight tunnel. Ninety and 84% males flew to the pheromone source, respectively. However, with the addition ofZ11–16∶OH to the pheromone blend, none of the wild males flew upwind to the stimulus source, whereas 36% of the lab-reared males completed the flight. It is suggested that prolonged inbreeding in closed quarters rendered these males less discriminating to qualitative differences in a pheromone blend.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 102
    ISSN: 1573-1561
    Keywords: Hydraecia micacea ; Lepidoptera ; Noctuidae ; potato stem borer ; sex pheromones ; field trapping ; reproductive behavior ; tetradecenyl acetate ; (Z)-9-tetradecenyl acetate ; (E)-11-tetradecenyl acetate ; (Z)-11-tetradecenyl acetate
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract Behavior of males ofHydraecia micacea (Esper) responding to virgin females and to synthetic pheromone blends were investigated in a laboratory wind tunnel. The synthetic blend consisted of saturated 14∶Ac (68.9%),Z9–14∶Ac (3.4%),E11–14∶Ac (14.6%), andZ11–14∶Ac (13.1%). Virgin females were significantly better lures than the four-component synthetic blend for most behaviors. By deleting components individually from the four-component blend,Z9–14∶Ac,Z11–14∶Ac, and saturated 14∶Ac were found to be necessary for communication butE11–14∶Ac was found to have no effect on typical pheromone-mediated reproductive behaviors. Close-range studies suggested that chemicals of low volatility, released from moths, were important in eliciting copulation attempts. Field studies reinforced laboratory findings regarding the effectiveness of different lures and indicated thatHeliothis traps were the most effective for monitoring.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 103
    ISSN: 1573-1561
    Keywords: Spodoptera exempta ; Lepidoptera ; Noctuidae ; sex pheromone ; (Z)-9-tetradecenal ; (Z)-9-tetradecenyl acetate ; (Z)-11-tetradecenyl acetate ; (Z,E)-9,12-tetradecadienyl acetate ; (Z)-9-tetradecen-1-ol ; (Z)-11-hexadecenyl acetate
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract Ovipositor washings from virgin femaleSpodoptera exempta (Walker) (Lepidoptera: Noctuidae) were analyzed by high-resolution gas chromatography (GC) linked to a male electroantennogram (EAG). GC retention times of the two major EAG responses observed were consistent with their assignment as (Z)-9-tetradecenyl acetate and (Z,E)-9,12-tetradecadienyl acetate, as previously identified. However, three other EAG responses were also noted that had GC retention times consistent with (Z)-9-tetradecenal, (Z)-9-tetradecen-1-o 1, and (Z)-11-hexadecenyl acetate. The components were present in the ratio of 100∶5∶1.5∶3.5∶4, respectively. Further analysis of the ovipositor washings by GC linked to a mass spectrometer (GC-MS) confirmed these findings and indicated the presence of a sixth component consistent with (Z)-11-tetradecenyl acetate present at 2 % of the major component. In field tests carried out in Kenya, (Z)-11-hexadecenyl acetate was the only newly identified component to enhance the catch of the original two-component mixture when presented in their natural ratio. The addition of (Z)-9-tetradecen-1-ol reduced catch, while (Z)-9-tetradecenal and (Z)-11-tetradecenyl acetate had no apparent effect.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 104
    ISSN: 1573-1561
    Keywords: Mountain-ash bentwing ; Leucoptera scitella ; Lepidoptera ; Lyonetidae ; (R,R)-5,9-dimethylheptadecane ; (R,S)-5,9-dimethylheptadecane ; (S,R)-5,9-dimethylheptadecane ; (S,S)-5,9-dimethylheptadecane ; 5,9-dimethylhexadecane ; trapping ; behavior ; sex pheromone ; asymmetric synthesis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract Among the pure stereoisomers of 5,9-dimethylheptadecane, a previously identified sex pheromone component ofLeucoptera scitella L., only theS,S isomer yielded trap captures in the field. The addition of the other stereoisomers had no effect on cathes. The addition of low percentages of racemic 5,9-dimethylhexadecane, a previously identified minor component in the sex pheromone, did not influence trap catches or alter behavior of males approaching an attractant source in the field.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 105
    ISSN: 1573-1561
    Keywords: Campoletis sonorensis ; Hymenoptera ; Ichneumonidae ; Heliothis zea ; Lepidoptera ; Noctuidae ; 2-tridecanone ; trichomes ; Lycopersicon hirsutum f.glabratum ; tomato ; plant defense ; allelochemical
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract Greenhouse-grown plants of five tomato lines varying in their level of 2-tridecanone-mediated resistance toManduca sexta (L.) andLeptinotarsa decemlineata (Say) were found to adversely affect larvae ofCampoletis sonorensis (Cameron), a larval endoparasitoid ofHeliothis zea (Boddie), in a manner directly related to their level of resistance. The parasitoid larvae, which emerge as fifth instars from their host and construct a cocoon on the foliage of their hosts' host plant, suffered extensive mortality during cocoon spinning on highly resistant foliage. Mortality was greatest (82%) on the highly resistant plants ofLycopersicon hirsutum f.glabratum (accession PI 134417) and an F1 backcross [(L. esculentum × PI 134417) × PI 134417] selection. Mortality was intermediate (40 and 28%, respectively) on backcross selections with moderate and low levels of resistance and least (8%) on susceptibleL. esculentum. Removal of the glandular trichomes, which contain 2-tridecanone in their tips, from the foliage eliminated differences in parasitoid mortality among plant lines. Bioassays of 2-tridecanone indicated that it is acutely toxic to fifth instarC. sonorensis larvae at the quantities associated with highly resistant foliage and produces symptoms identical to those observed on resistant foliage. 2-Undecanone, a second methyl ketone present in the glandular trichomes of resistant foliage, was also toxic toC. sonorensis larvae, but significantly less so than 2-tridecanone. The results support the hypothesis that 2-tridecanone is responsible for the observed mortality ofC. sonorensis larvae during cocoon construction on resistant foliage.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 106
    ISSN: 1573-1561
    Keywords: Fluorinated pheromone analog ; western spruce budworm ; Choristoneura occidentalis ; Lepidoptera ; Tortricidae ; electroantennogram ; wind tunnel ; toxicity ; (E)-14-fluorotetradec-11-en-1-ol
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract ω-Fluorinated (E)-11-tetradecenal (14F-E11-14: Al) was synthesized using 1,10-decanediol as a starting compound. Male and female western spruce budworm,Choristoneura occidentalis Freeman, moths exposed to 14F-E11-14: Al had LC50s (CI) of 12.0 (7.4–19.5) µg and 41.7 (22.7–76.2) µg, respectively. Antennectomized moths had lower mortality rates than normal moths. 14F-E11-14:Al elicited slightly lower amplitudes than 97:3 (E/Z)-11-tetradecenal (E/Z11-14:Al) in electroantennogram studies, but the lag or recovery period following excitation by 14F-E11-14:Al was much lower than forE/Z11-14:Al at the same concentrations. 14F-E11-14:Al andE11-14:Al evoked similar responses from male moths in wind-tunnel evaluations but neither compound was as effective as a virgin female in stimulating moths to fly upwind to contact the lure.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 107
    Electronic Resource
    Electronic Resource
    Springer
    Journal of chemical ecology 15 (1989), S. 141-168 
    ISSN: 1573-1561
    Keywords: Hymenoptera ; Braconidae ; Microplitis croceipes ; Heliothis zea ; Lepidoptera ; Noctuidae ; anemotaxis ; parasitoid ; jet plumes ; optomotor response ; semiochemicals
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract Odor-mediated host-searching by femaleMicroplitis croceipes, a braconid endoparasitoid of larvalHeliothis species, was studied in a flight tunnel. Volatiles emitted by third-instarH. zea feeding on cowpea seedling leaves were released and carried with the wind, resulting either in an irregularly shaped plume, or injected with high velocity, resulting in a conically shaped jet plume. Flight maneuvers ofM. croceipes had a higher stereotype in jet plumes compared to irregularly shaped plumes. Variation in odor concentration in jet plumes due to intermittent feeding of the host larvae did not affect the number of flights. At the levels employed, odor concentration did not alter the rate of upwind progress in jet plumes. Because air velocity inside a jet increases in the upwind direction,M. crocepies regulates its ground-speed during its approach to the odor source.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 108
    ISSN: 1573-1561
    Keywords: Heliothis subflexa ; Lepidoptera ; Noctuidae ; attractant ; kairomone ; groundcherry ; Physalis angulatus ; flight tunnel bioassay ; plant-insect interaction
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract Mated femaleHeliothis subflexa (Gn.) (HS) moths 1–7 days old responded positively in a Plexiglas flight tunnel to an attractant extracted with methanol from fresh whole-leaf washes of groundcherry,Physalis angulata L. Response to the groundcherry extract, as indicated by plume-tracking (i.e., upwind flight toward the odor source) and contact with the chemical dispenser did not change significantly during the first 5 hr of scotophase. Overall, ca. 50% of the responding moths also landed on the chemical dispenser; ca. 50% of the moths that landed also deposited eggs. There were no significant differences in the behavioral responses of females mating only once and those that had mated two or more times. Virgin females and male moths were significantly less responsive to the groundcherry attractant than mated females. The flight tunnel bioassay described provides an excellent system for evaluating plant allelochemics associated with host-plant selection.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 109
    Electronic Resource
    Electronic Resource
    Springer
    Journal of chemical ecology 15 (1989), S. 457-465 
    ISSN: 1573-1561
    Keywords: Sex pheromones ; Planotortrix excessana ; Lepidoptera ; Tortricidae ; leafroller ; intraspecific variation ; (Z)-5-tetradecenyl acetate ; (Z)-7-tetradecenyl acetate
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract Two components, (Z)-5- and (Z)-7-tetradecenyl acetates, in the sex pheromone gland of aPlanotortrix excessana sibling species, were found to vary continuously from a ratio of 3∶97 to 71∶29 in individual female moths reared from wild larvae collected around New Zealand. Two laboratory colonies were established from populations representing extremes of these ratios. Although both the ratios and the total quantities of the components in individual female moths from both colonies were significantly different from each other, there was a small number of females that overlapped in both ratio and quantity. The variation was confirmed as intraspecific in a field cage experiment with male moths from both populations mating with tethered female moths from both populations.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 110
    Electronic Resource
    Electronic Resource
    Springer
    Journal of chemical ecology 15 (1989), S. 2019-2029 
    ISSN: 1573-1561
    Keywords: Actias luna ; Lepidoptera ; Saturniidae ; detoxification enzymes ; enzyme induction ; glutathione transferase ; Juglandaceae ; juglone ; nutritional ecology ; plant-insect interactions ; quinone reductase
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract The effects of food plant on larval performance and midgut detoxification enzymes were investigated in larvae of the luna moth,Actias luna. Neonate larvae were fed leaves of black cherry, cottonwood, quaking aspen, white willow, red oak, white oak, tulip tree, paper birch, black walnut, butternut, or shagbark hickory. First instar survival, larval duration, and pupal weights were monitored as indices of food quality. Midgut enzyme preparations from fifth instars were assayed for β-glucosidase, quinone reductase, polysubstrate monooxygenase, esterase, and glutathione transferase activities. Larval survival on seven of the 11 plant species, including several recorded host plants, was extremely poor. Larvae performed well, and quite similarly, on birch, walnut, butternut, and hickory. Activities of all enzyme systems except β-glucosidase were significantly influenced by larval host plant. Of the systems assayed, quinone reductase and glutathione transferase activities were especially high. Comparisons of these values with published values for other Lepidoptera support the hypothesis that these enzyme systems are involved in conferring tolerance to juglone and related quinones occurring in members of the plant family Juglandaceae. Results suggest that host plant utilization by luna is more specialized at the individual or population level than at the species level and that biochemical detoxification systems may play a role in such specialization.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 111
    Electronic Resource
    Electronic Resource
    Springer
    Journal of chemical ecology 15 (1989), S. 2101-2113 
    ISSN: 1573-1561
    Keywords: Pieris rapae ; Trichoplusia ni ; Lepidoptera ; Pieridae ; Noctuidae ; proteases ; digestive enzymes ; proteinase inhibitors ; dietary protein requirement
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract In their larval luminal midgut fluid,Trichoplusia ni (Lepidoptera: Noctuidae) andPieris rapae (Lepidoptera: Pieridae) contain endopeptidases as their primary proteases. Neither species has detectable exopeptidase activity. Studies using enzyme-specific substrates and inhibitors demonstrate that the endopeptidases are serine proteinases (both trypsinlike and chymotrypsinlike) with histidine at the active site. Optimal pH for the tryptic and chymotryptic activity is 8.5 and 8.0, respectively, forT. ni. and 8.0 and 9.0, respectively, forP. rapae. The efficiency of proteolytic digestion (as measured by the rate of in vitro digestion of a standard protein by the midgut luminal fluid) is positively correlated with the larval dietary protein requirement and is significantly influenced by the ratios of tryptic to chymotryptic activity present in the gut lumen of these two species of Lepidoptera.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 112
    Electronic Resource
    Electronic Resource
    Springer
    Journal of chemical ecology 15 (1989), S. 2161-2169 
    ISSN: 1573-1561
    Keywords: Cabbage butterfly ; Pieris rapae ; Lepidoptera ; Pieridae ; Erysimum ; oviposition deterrent ; cardenolides
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract Avoidance ofErysimum cheiranthoides for oviposition byPieris rapae has been attributed to the presence of water-soluble deterrents. The active material was extracted inton-butanol and isolated by a series of HPLC separations. TLC of the active fraction and visualization of individual constituents with Kedde's reagent indicated that cardenolides are responsible for deterring oviposition. UV spectra were also characteristic of cardenolides. Bioassays of selected known cardenolides revealed a general lack of activity, except for cymarin, which was as strongly deterrent as the most prominent cardenolide isolated in pure form fromE. cheiranthoides. The results suggest that cardenolides in this plant can explain its escape from cabbage butterflies, but specific structural features of the glycosides are necessary for oviposition-deterring activity.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 113
    Electronic Resource
    Electronic Resource
    Springer
    Journal of chemical ecology 15 (1989), S. 2233-2245 
    ISSN: 1573-1561
    Keywords: Sex pheromone ; Lepidoptera ; Noctuidae ; Heliothis peltigera ; capillary chromatography ; DMDS derivatization ; behavioral tests ; field work
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract Ten compounds were found in the sex pheromone glands ofHeliothis peltigera (Schiff) and identified as tetradecenal, (Z)-9-tetradecenal, (Z)-9-tetradecenol, (Z)-9-tetradecenyl acetate, hexadecanal, (Z)-7-hiexadecenal, (Z)-9-hexadecenal, (Z)-11-hexadecenal, (Z)-11-hexadecenol, and (Z)-11-hexadecenyl acetate. Behavioral tests in a wind tunnel and subsequent trapping studies conducted in the field indicated that (Z)-11-hexadecenal and (Z)-9-tetradecenal are the main pheromone components ofH. peltigera. Addition of (Z)-11-hexadecenol to the binary blend did not enhance the capture of males ofH. peltigera, but it decreased the number of males of the sympatricH. armigera. Rubber septa impregnated with a mixture of 2 mg (Z)-11-hexadecenal + 1 mg (Z)-9-tetradecenal + 0.6 mg (Z)-11-hexadecenol are recommended for monitoringH. peltigera.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 114
    Electronic Resource
    Electronic Resource
    Springer
    Journal of chemical ecology 15 (1989), S. 121-128 
    ISSN: 1573-1561
    Keywords: Spodoptera frugiperda ; Lepidoptera ; Noctuidae ; Meliaceae ; neem ; insecticides ; limonoids ; seed extracts
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract Hexane and ethanol extracts of seeds from 10 plant species (including neem—Azadirachta indica A. Juss.) of the family Meliaceae were incorporated into artificial diet at various doses and fed to fall armyworm [Spodoptera frugiperda (J. E. Smith) (Lepidoptera: Noctuidae)] larvae in nochoice tests. All produced significant mortality, reduced larval growth rate, increased time to pupation, or all three, at some concentration. The two highest doses of all of the ethanol extracts caused 100% mortality before pupation, but the hexane extracts tended to be less effective.Aglaia cordata Hiern. ethanol extract was as potent as the comparable neem seed extract at virtually all levels, and its hexane extract was active at much lower concentrations than the neem extract was. The sublethal effects (slower growth and increased time to pupation) were usually detectable at lower doses of extract than mortality was.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 115
    ISSN: 1573-1561
    Keywords: Lepidoptera ; Tortricidae ; Croesia curvalana ; blueberry leaftier moth ; sex pheromone components ; (E)-11-tetradecenal ; (Z)-11-tetradecenal ; (E)-11-tetradecenyl acetate ; (Z)-11-tetradecenyl acetate
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract The GC-MS and GC-EAD analyses of sex-gland components and sex-gland-released volatiles have identified (E)- and (Z)-11-tetradecenal (90∶10) and (E)- and (Z)-11-tetradecenyl acetate (85∶15) as components of the sex pheromone chemical communication system ofCroesia curvalana (Kearfott). The aldehyde-to-acetate ratio of 9∶1 was found in the gland-released components. This blend at a 0.1–1 μg/day release rate from PVC lures was shown to be as effective as virgin females in the trapping of maleC. curvalana.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 116
    ISSN: 1573-1561
    Keywords: Pine beauty moth ; Panolis flammea ; Lepidoptera ; Noctuidae ; sex attractant ; monitoring trap ; chemoorientation ; odor plume ; trap interference
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract Catches of malePanolis flammea in traps baited with lures containing 25 μg of sex attractant are enhanced when in the proximity of traps baited with 125-μg lures. The degree of enhancement is increased as the intertrap distance is decreased, and when the low-dose trap is upwind of the high-dose one. The patterns of alteration in trap catch suggest that moths initially attracted by one lure may divert into other traps, which may be either upwind of the original trap (“overshooting”), or downwind (“undershooting”). “Overshooting” can result in up to fivefold increases in catch and may provide a useful method for estimating the attractant zone of particular lure/trap combinations.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 117
    Electronic Resource
    Electronic Resource
    Springer
    Journal of chemical ecology 15 (1989), S. 2565-2575 
    ISSN: 1573-1561
    Keywords: Oviposition stimulant ; host selection ; butterfly ; Lepidoptera ; Papilionidae ; Atrophaneura alcinous ; Aristolochia debilis ; aristolochic acid ; sequoyitol ; Synergist
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract Oviposition stimulants of an Aristolochiaceae-feeding swallowtail butterfly,Atrophaneura alcinous, were isolated from the leaves ofAristolochla debilis and characterized as a mixture of aristolochic acids and sequoyitol. An artificial blend of these components applied to filter paper induced a significant oviposition response by the female butterflies, identical to that elicited by intact leaves of theAristolochia host plant.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 118
    Electronic Resource
    Electronic Resource
    Springer
    Journal of chemical ecology 15 (1989), S. 2625-2634 
    ISSN: 1573-1561
    Keywords: Pheromone ; disruption ; atmospheric permeation ; neurophysiology ; Heliothis zea (Boddie) ; Noctuidae ; Lepidoptera
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract For some species, chemical analogs have been identified that can substitute for the major pheromone component and reduce pheromone-trap captures in atmospheric permeation experiments. The ability to substitute these analogs for the major pheromone component in field tests raises the question: Do the same set of olfactory receptor neurons on the insects' antennae respond to both the major component and the effective structural analogs? To investigate this question, extracellular responses were recorded from single sensilla on the antennae of maleHeliothis zea (Boddie) (Lepidoptera: Noctuidae) to stimulation with increasing doses of (Z)-11-hexadecenal, the major pheromone component, (Z)-9-tetradecen-1-ol formate, and (Z)-1,12-heptadecadiene. Both (Z)-9-tetradecen-1-ol formate and (Z)-1,12-heptadecadiene can substitute for (Z)-11-hexadecenal in trap disruption experiments and affect the sexual behavior of males, although neither has been identified in the volatiles released by calling females. All three compounds elicited responses from the same class of pheromone-sensitive receptor neurons over a range of stimulus concentrations. At equivalent stimulus concentrations, however, (Z)-11-hexadecenal elicited about a 10-fold greater response than (Z)-1,12-heptadecadiene. (Z)-9-Tetradecen-1-ol formate elicited a response slightly higher than, but not significantly different from, the response to (Z)-1,12-heptadecadiene.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 119
    Electronic Resource
    Electronic Resource
    Springer
    Journal of chemical ecology 15 (1989), S. 47-60 
    ISSN: 1573-1561
    Keywords: Cisseps fulvicollis ; Ctenucha virginica ; Halysidota tessellaris ; hydroxydanaidal ; pyrrolizidine alkaloids ; Eupatorium maculatum ; Lepidoptera ; Arctiidae ; Ctenuchinae ; coremata ; male pheromones ; attractants
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract Adults of three species of arctiid moths (Cisseps fulvicollis, Ctenucha virginia, andHalysidota tessellaris) are attracted to plants that contain pyrrolizidine alkaloids (PAs). The moths use olfactory cues to locate these plants, then feed on leaves, flowers, and roots with the proboscis. To investigate the chemical basis of attraction, sticky traps were baited with roots of a PA-containing plant,Eupatorium maculatum, alkaloids ofE. maculatum, and several derivatives of these alkaloids. Volatile derivatives of the bicyclic pyrrolizidine skeleton attracted all three arctiid species. The dihydropyrrolizines, (S)-(+)-hydroxydanaidal and (R)-(−)-hydroxydanaidal, proved to be the most attractive compounds tested, accounting for over 70% of the moths captured. Different alkaloid derivatives attracted different proportions of male and femaleCisseps. Both (S)-(+)-hydroxydanaidal (52% male) and (R)-(−)-hydroxydanaidal (71% male) attracted a significantly lower percentage ofCisseps males thanE. maculatum roots (87% male).Cisseps males possess eversible scent organs (coremata) that are displayed during courtship. Analysis of corematal extracts revealed the presence of hydroxydanaidal.Cisseps moths thus resemble danaine and ithomiine butterflies, both in their attraction to PA sources and in the presence of PA derivatives in the male scent organs.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 120
    ISSN: 1573-1561
    Keywords: European corn borer ; Ostrinia nubilalis ; Lepidoptera ; Pyralidae ; corn ; DIMBOA ; 2,4-dihydroxy-7-methoxy-1,4-benzoxazin-3-one ; tritiated DIMBOA ; toxicokinetics ; topical application ; body burden ; growth
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract 2,4-Dihydroxy-7-methoxy-1,4-benzoxazin-3-one (DIMBOA), the major hydroxamic acid present in corn, and its tritiated derivative, were prepared synthetically for use in the determination of the toxicokinetics of this insect deterrent in the European corn borer (ECB),Ostrinia nubilalis. In growth studies with DIMBOA (0, 0.05, 0.2, and 0.5 mg/g diet), the mean time to pupation and adult emergence were significantly lengthened by an increase in concentration. Pupal and adult weights, for both female and male, decreased with an increase in concentration. Increased larval and pupal mortality occurred at the highest concentration of DIMBOA. DIMBOA, at concentrations of 0.2 and 0.5 mg/g diet, resulted in a decrease in the number of egg masses produced per female, and at 0.5 mg/g diet, in a decrease in the number of eggs per egg mass. Larvae fed from the neonate stage on a diet containing 0.2 mg [3H]- + [1H]DIMBOA/g diet showed an increase in the content of label from fourth to fifth instar, but levels declined at pupation and emergence. A large amount of the labeled compounds was excreted by the insect in the pupal case. In dose-related studies, both uptake and excretion increased with an increase in concentration of DIMBOA (0.05, 0.2, 0.4 mg/g diet), while a body burden (concentration in the tissues/concentration in the frass) of approximately 0.25 was maintained for all concentrations. At the highest dose of DIMBOA (0.4 mg/g), the ECB increased consumption, possibly to compensate for the toxic effects of the compound. In topical application studies, elimination of the labeled compound in the frass was rapid, reaching 65% by 4 hr and 88% by 48 hr. Accumulation of label in tissues other than hemolymph was low. The results show that the ECB does possess adaptive mechanisms to deal with the effects of this host-derived compound.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 121
    Electronic Resource
    Electronic Resource
    Springer
    Journal of chemical ecology 15 (1989), S. 2347-2355 
    ISSN: 1573-1561
    Keywords: Black swallowtail ; Papilio polyxenes ; Lepidoptera ; Papilionidae ; microsomal cytochrome P450 ; induction ; xanthotoxin ; furanocoumarins ; plant defensive compounds
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract Xanthotoxin is a phototoxic allomone found in many of the host plants of the black swallowtail,Papilio polyxenes (Lepidoptera: Papilionidae). When added to the diet of final instar larvae, xanthotoxin can induce the cytochrome P450 monooxygenase (P450) activity in midgut microsomes by which it is detoxified. Induction is dose-dependent, increasing sevenfold when larvae feed on parsley treated topically with xanthotoxin at 0.5 or 1.0% fresh weight. Although xanthotoxin exerts much of its toxic effects when photoactivated by ultraviolet light, induction of P450 activity did not differ in the presence or absence of ultraviolet light. Despite a 4.7-fold induction of xanthotoxin-metabolizing P450 activity, total P450 content measured in the same microsomal samples did not increase significantly. These data indicate that multiple forms of P450 exist in the black swallowtail midgut and that they are differentially induced by xanthotoxin.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 122
    ISSN: 1573-1561
    Keywords: Sex pheromone ; Cydia toreuta ; Lepidoptera ; Tortricidae ; Olethreutinae ; (E,Z)-8,10-dodecadienyl acetate
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract The sex pheromone ofCydia toreuta (Grote), the eastern pine seedworm, was investigated using electroantennogram (AG) measurements, gas chromatography (combined GC-FID-EAD) measurements, and field tests. (E,Z)-8,10-dodecadienyl acetate (E,Z8,10-12:Ac) and (E,E)-8,10-dodecadienyl actetate (E,E8,10-12: Ac) produced both the highest EAG and EAD responses. Only a single antennal stimulatory peak was observed when female abdominal tip extracts were analyzed by GC-FID-EAD, which corresponded exactly with that of authenticE,Z8,10-12: Ac. Field tests confirmedE,Z8,10-12: Ac as the major pheromone component. TheE,Z isomer by itself caught equivalent numbers of male moths as did caged females. The addition of theE,E isomer to theE,Z form increased trap catch, although not significantly (P = 0.05). The addition of (Z,Z)-8,10-dodecadienyl acetate to theE,Z isomer significantly (P=0.05) reduced trap catch, while the addition of (Z,E)-8,10-dodecadienyl acetate to theE,Z form also decreased trap catch, but not significantly (P=0.05).
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 123
    ISSN: 1573-1561
    Keywords: Mating behavior ; Parasitoids ; Cotesia (=Apanteles)marginiventris ; Hymenoptera ; Braconidae ; Spodoptera frugiperda ; Lepidoptera ; Noctuidae
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract Two blends of fall armyworm,Spodoptera frugiperda (J.E. Smith), pheromonal components were evaluated in the laboratory for possible close-range effects on mating and oviposition byCotesia marginiventris (Cresson). Neither a two- nor a five-component blend had any significant effect on mating or parasitization ofS. frugiperda larvae by this parasitoid. Dosages of 200, 400, and 800 μg were tested.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 124
    Electronic Resource
    Electronic Resource
    Springer
    Journal of comparative physiology 159 (1989), S. 359-370 
    ISSN: 1432-136X
    Keywords: Diuretic hormone ; Insect neurohormones ; Heliothis ; Lepidoptera ; Diuresis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Diuretic factors were studied in the central nervous system of larvae of the tobacco budworm,Heliothis virescens, using [14C]urea as a sensitive indicator for water movement through isolated Malpighian tubules. The assay required Na+ and a pH of 6.0–6.2 for maximum activity. Malpighian tubules had high secretory activity in feeding larvae of the fifth instar, but the activity declined during the burrowing-digging stage that preceded pupation. Malpighian tubules from starved larvae showed a greater response to extracts of nervous tissues than did tubules from feeding larvae, and extracts showed a dose-response relationship with fluid secretion. Diuretic activity was distributed throughout all parts of the central nervous system with the brain having the most activity. Brain extracts increased fluid secretion by in vitro Malpighian tubules by more than 3-fold and doubled the rate of dye clearance from the hemolymph in vivo. Diuretic activity in nervous tissue extracts was unaffected by boiling but sensitive to proteases. Fluid secretion by in vitro tubules was increased by cAMP, dbcAMP, theophylline, octopamine and dopa. These studies provide evidence for the presence of diuretic factors in the central nervous system ofH. virescens larvae and describe a sensitive bioassay for these factors.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 125
    ISSN: 1612-1112
    Keywords: Column liquid chromatography ; Microcrystalline cellulose triacetate ; Molecular modeling ; Computer graphics
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary Molecular modeling and energy calculations have been used to study the chromatographic separation of aromatic compounds on microcrystalline cellubose triacetate. A linear relationship has been found between the logarithms of the capacity factors and the energy values of the interaction of these compounds with this stationary phase. The interaction energies have been calculated for two different spatial dispositions of the solutes in relation to the sorbent.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 126
    ISSN: 1612-1112
    Keywords: Column liquid chromatography ; Liquid crystals ; Synthesis of new bonded phases
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary A compound which becomes a liquid crystal when bonded to a polysiloxane was reacted with dimethylchlorosilane to produce a reagent suitable for bonding to a silica surface. After the silanization reaction was complete, the product was characterized by elemental analysis, diffuse reflectance Fourier transform Infrared Spectroscopy (DRIFT), CP/MAS carbon-13 NMR and differential scanning calorimetry (DSC). Preliminary chromatographic testing was done by retention index measurements using the alkylarylketone homologous series and by measuring the separation factor, α, for anthracene/phenanthrene at two different mobile phase compositions.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 127
    Electronic Resource
    Electronic Resource
    Springer
    Chromatographia 27 (1989), S. 633-638 
    ISSN: 1612-1112
    Keywords: Column liquid chromatography ; Adsorption isotherms ; Equilibria criteria ; Silica and carbon adsorbents ; Aromatic compounds
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary Examples of high-performance liquid chromatography (HPLC) are given for the determination of adsorption equilibrium and distribution coefficients, calculation of excess adsorption isotherms from solutions ranging from 10−7 to 10−1 mole fraction, changes in activity coefficient of the component predominantly adsorbed from solution and substitution enthalpy. These examples stem from studies of HPLC and the static adsorption of benzene, anisole and benzaldehyde from solutions in n-heptane on macroporous silica and active carbon at various temperatures. A criterion is suggested for evaluating equilibrium in the HPLC process. The potential of size-exclusion chromatography (SEC) for evaluating the volume and predominant diameter of adsorbed pores as well as pore diffraction are discussed. Prospects for HPLC application to molecularstructural analysis and other purposes are discussed briefly.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 128
    Electronic Resource
    Electronic Resource
    Springer
    Chromatographia 27 (1989), S. 118-122 
    ISSN: 1612-1112
    Keywords: Column liquid chromatography ; Reversed-phase chromatography ; Non-aqueous reversed-phase chromatography ; Polycyclic aromatic hydrocarbons ; Solvent strength
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary Elution strengths of 11 common HPLC solvents on a polymeric C18 phase were compared using a marker set of polycyclic aromatic hydrocarbons. Naphthalene, pyrene, benzo[ghi]perylene, and three larger naphthologues of 8, 10, and 12 rings (constituting a “naphthalene zigzag” series) were chosen because they span the solvent strength range up to and including the strongest solvents, tetrahydrofuran (THF) and chlorobenzene. Four pairs of similarly shaped isomers were used to probe solvent selectivity. With the exception of THF, HPLC solvent strength correlated with observed red shifts of fluorescence band maxima in each solvent. For THF, the pure solvent and blended mixtures behaved quite differently.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 129
    Electronic Resource
    Electronic Resource
    Springer
    Chromatographia 27 (1989), S. 156-158 
    ISSN: 1612-1112
    Keywords: Column liquid chromatography ; Mobile phase retention time ; Capacity factor ; Negative capacity factor
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary Numerous ideas and procedures have been suggested in the literature for the determination of tm, the retention time of a non-retained species, in high-performance liquid chromatography. In some cases chromatograms have been obtained showing sample components eluting prior to the assumed non-retained species. This phenomenon results in apparent negative capacity factors for the species in question. We have proposed a method employing small inorganic anions which results in a limiting value for tm and eliminates apparent negative capacity factors.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 130
    Electronic Resource
    Electronic Resource
    Springer
    Chromatographia 27 (1989), S. 228-232 
    ISSN: 1612-1112
    Keywords: Column liquid chromatography ; Reversed-phase ; 13C n.m.r. ; Arginine-aldehyde peptides ; GYKI-14166
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary High-performance liquid chromatographic and13C n.m.r. spectrometry methods were used for the investigation of peptides containing arginine-aldehyde moiety. Investigation of a model compound, N-benzoyl-Arg-H, showed that in an acidic mobile phase peptides containing the arginine-aldehyde group elute in three characteristic peaks. The components of the peaks were found to be constituents of an equilibrium mixture. The structures of the two components were identified, one as the aldehyde hydrate, the other as the cyclanol derivative. The reactivity of TRIS (HCl) buffer at pH 8.5 with the arginine aldehyde moiety was used for the assignment of the equilibrium structures.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 131
    ISSN: 1612-1112
    Keywords: Column liquid chromatography ; Reversed-phase ; Ion-pair ; Recoveries ; Hepatocytes ; Purine compounds
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary Three groups of metabolites were analyzed in extracts of rat hepatocytes by an HPLC method: (i) nucleotides (ATP, ADP, AMP, GTP, GDP, UTP, UDP, IMP, UMP), (ii) nucleosides and nucleobases (adenosine, adenine, guanosine, inosine, xanthine, hypoxanthine, uridine) and (iii) inhibitors of xanthine oxidoreductase (oxypurinol, allopurinol). Perchloric acid extracts were neutralized with K2CO3/triethanolamine and analyzed at 254 nm by reversed-phase ion-pair high-performance liquid chromatography. The nucleotides and their derivatives were separated with a gradient elution using 10 mM NH4H2PO4/2 mM t-butylammonium-phosphate and acetonitrile. Recovery values were estimated for the extraction procedure used. The method was applied to the investigation of nucleotide metabolism of hepatocytes of starved rats at anoxia and reoxygenation.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 132
    Electronic Resource
    Electronic Resource
    Springer
    Chromatographia 27 (1989), S. 316-320 
    ISSN: 1612-1112
    Keywords: Column liquid chromatography ; Ion chromatography ; Silica-based cation-exchanger ; Trimethylsilyl chlorosulfonate ; Lanthanides
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary A low exchange-capacity, silica-based cation-exchanger for use in ion chromatography has been synthesized. (p-Trimethylsilyl)benzyl-dimethylchlorosilane (TBDCS) reacts with trimethylsilyl chlorosulfonate (TMCS) to produce a compound sulfonated in the para position of the type ArSO2OSi (CH3)3, which is bonded to 5 μm porous silica beads and hydrolysed to the corresponding arylsulfonic acid. The product is hydrophilic and has a high degree of sulfonation, efficiencies of packed columns reaching about 40,000–50,000 plates per meter for the separation of the Mn2+ ion. The new stationary phase has been applied to the ion chromatography of some organic and inorganic ions. It is notable that 14 lanthanides can be separated by isocratic elution about one hour on a 150×4·6 mm column, with 4 mM ethylenediamine and 6 mM α-hydroxyl-isobutanoic acid (pH 3.67) as mobile phase.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 133
    Electronic Resource
    Electronic Resource
    Springer
    Chromatographia 27 (1989), S. 191-193 
    ISSN: 1612-1112
    Keywords: Column liquid chromatography ; Dansyl amino acids ; Chemiluminescence ; Bis(2,4,6-Trichlorophenyl)oxalate, (TCPO) ; Enhancement of luminescence
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary The dansylated amino acids alanine, glutamic acid, methionine and norleucine were separated by reversedphase HPLC and detected via chemical excitation using the post-column, TCPO-peroxyoxalate reaction system. Enhancement of the chemiluminescence emission was achieved by including the surfactant Triton X-100 in the eluent.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 134
    ISSN: 1612-1112
    Keywords: Column liquid chromatography ; Reverse-phase chromatography ; Elastin Hydrolysis measurement ; On-line post-column derivatization
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary Excessive breakdown of elastin, a structural protein, may be related to aortic disease and emphysema. Since L-valyl-L-proline occurs in high concentrations in elastin, a rapid and sensitive method using HPLC with post-column on-line derivatization was used to measure the dipeptide from swine aortic tissue, and the amount of elastin present was determined. Elastin was extracted by alkaline hydrolysis. After neutralization and filtration, the sample was injected onto a ODS-2 gel column, and the dipeptide was eluted by a linear gradient of 0 to 10% of 1-propanol in 50 mM heptafluorobutyrate, pH 3, at a flow rate of 1 ml/min. The eluent was reacted with fluorescamine at pH 8.6, and fluorescence was detected at an excitation wavelength of 395 nm and a 455 nm cutoff emission filter.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 135
    Electronic Resource
    Electronic Resource
    Springer
    Chromatographia 27 (1989), S. 449-454 
    ISSN: 1612-1112
    Keywords: Column liquid chromatography ; Ion exchange and affinity columns in series ; Porcine pancreatic enzymes ; Trypsin and elastase
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary In order to separate and purify some of the enzymes contained in porcine pancreas, operation of an ion-exchange column in series with an affinity column has been used. The enzymes dealt with possess very similar molecular weights, isoelectric points and active sites. Hence they are difficult to separate and purify by traditional separation and/or purification methods. CM-Sepharose anion-exchange resin adsorbs elastase and trypsin at low pH (4.5) and desorbs them at high pH (9.0) and high ionic strength. Chitin-CHOM affinity adsorbent adsorbs trypsin at high pH (8.0) and desorbs it at low pH (2.5). By virtue of this complementary relationship two chromatographic columns were connected in series for facilitating the separation and purification of elastase and trypsin from porcine pancreas. The result showed that the specific activities of elastase and trypsin had been increased 16 and 22 fold respectively.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 136
    Electronic Resource
    Electronic Resource
    Springer
    Chromatographia 27 (1989), S. 472-474 
    ISSN: 1612-1112
    Keywords: Column liquid chromatography ; Hydrous titanium oxide ; Anion exchange ; Polyvalent anions
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary Hydrous titanium oxide (HTiO), prepared under varying conditions of precipitation, has been studied for its anion exchange behaviour. Its chemical and thermal stability has been examined. The stoichiometry of uptake for Cl− has been investigated using a36Cl radiotracer and the regeneration power of the exchanger checked. Distribution coefficients for halides and polyvalent anions have been determined and on the basis of sorption data some polyvalent anions have been separated using HTiO columns.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 137
    Electronic Resource
    Electronic Resource
    Springer
    Chromatographia 27 (1989), S. 509-512 
    ISSN: 1612-1112
    Keywords: Column liquid chromatography ; Flavonoids ; Crataegus ; Passiflora ; Matricaria ; Ginkgo
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary Flavonoids of Crataegus monogyna, Passiflora incarnata, Matricaria chamomilla and Ginkgo biloba extracts have been separated by isocratic elution on C18 columns using eluents based on C3 alcohols, tetrahydrofuran or dioxane. Satisfactory results have been obtained at compared to the low resolution achieved with the customary system acetonitrile-water-acetic acid.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 138
    Electronic Resource
    Electronic Resource
    Springer
    Chromatographia 28 (1989), S. 19-23 
    ISSN: 1612-1112
    Keywords: Column liquid chromatography ; Preparation of stationary phases ; Polymer coated stationary phases ; Polymer-octyl bonded phase
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary Polymethyloctylsiloxane-coated stationary phases have been prepared for liquid chromatography, by thermal reaction. The influence of the reaction conditions on retention and efficiency of test substances with different structures has been discussed. The materials have good stability in both acidic and basic eluents.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 139
    ISSN: 1612-1112
    Keywords: Column liquid chromatography ; Size exclusion ; Vesicular packing material ; Proteins and polymers
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary A new vesicular packing material — prepared from plant cell clusters by purification of the intact cell wall framework —is suitable for chromatography, giving high performance at low pressure gradients. The separation is achieved by dialysis through the cell wall, which is an ultrafilter membrane with an extremely sharp size limit of separation. Almost the whole of the stationary liquid phase is located within the vesicle (empty cell) lumina. In contrast to gel filtration vesicle chromatography gives a practically ideal separation of two size groups with an extremely short fractionation range. The size limit of separation was investigated by chromatography of proteins and other polymers. Group separation of molecules of a polydisperse dextran standard preparation showed that the critical Stokes' diameter for dextran permeation into the stationary liquid phase of the vesicular packing is 5 to 6 nm.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 140
    ISSN: 1612-1112
    Keywords: Column liquid chromatography ; Preparative scale separation ; 1,1-Dimethylethyl 4- and 5-bromo-trans-2-methylcyclohexane-1-carboxylate ; Trimedlure-related isomers ; Ceratitis capitata
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary A semi-preparative high-performance liquid chromatographic procedure on 5-μm silica was developed for the isolation of gram quantities of four 1,1-dimethylethyl 4- and 5-bromo-trans-2-methylcyclohexane-1-carboxylate isomers (trimedlure-related) for NMR studies and comparative biological evaluation as male medfly,Ceratitis capitata, attractants.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 141
    ISSN: 1612-1112
    Keywords: Column liquid chromatography ; Electrochemical detection ; Pseudouridine ; Creatinine ; Urine analysis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary The anodic behaviour of pseudouridine a modified nucleoside proposed as tumoral marker, has been studied at a mercury electrode. A method for its determination in urine samples by liquid chromatography with indirect anodic polarographic detection has been developed. The method is simple, highly selective and permits the direct injection of urine after dilution (1∶20) with mobile phase. Creatinine, which also gave an anodic response on mercury, could be simultaneously determined and used as an “internal standard” for Psi. This allowed the pseudouridine/creatinine ratio determination in a single run on the same specimen and the use of urine samples collected randomly instead of the 24h collection. The within-day RSD% for pseudouridine/ creatinine peak areas ratio was 3.4%.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 142
    Electronic Resource
    Electronic Resource
    Springer
    Chromatographia 28 (1989), S. 9-14 
    ISSN: 1612-1112
    Keywords: Column liquid chromatography ; Ester silicate silica gels ; Behaviour with organic bases ; Silanol groups ; Acidic centres
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary Silica gels produced from ester silicates (ES-gels) are excellent chromatographic supports. In comparison with other silica gels the RP-materials obtained from them show little peak tailing even with polar, and, in particular, with basic compounds. Gels produced by various manufacturing processes have been classified by adsorption with methyl pyridinium chloride. ES-gels yield very low methyl pyridinium chloride values and small asymmetry parameters. The results indicate that there are strongly acidic, structurally-related surface centres which cause peak tailing on most commercial gels. It was shown that surface silanols on silica gels do not, in themselves, lead to peak tailing.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 143
    Electronic Resource
    Electronic Resource
    Springer
    Chromatographia 28 (1989), S. 34-38 
    ISSN: 1612-1112
    Keywords: Column liquid chromatography ; Methylisothiazolones ; Preservatives ; Analysis of cosmetics
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary Antimicrobially active formulations based on 2-methyl-3(2H)-isothiazolone and 5-chloro-2-methyl-3(2H)-isothiazolone (Kathon CG, Euxyl K 100) are incorporated into manufactured cosmetics as preservatives. In this paper we report on the analysis of these active components by means of liquid chromatography. It is conventional for the original methylisothiazolone components in cosmetics to be analyzed by reversed phase high-performance liquid chromatography after column chromatographic separation and flash chromatographic purification. In our new analytical method the methylisothiazolones are converted into the respective β-thiosubstituted acrylamide derivatives, which are ionic substances, with the help of the nucleophilic reagent hydrogensulfite. An ion pair high-performance liquid chromatographic method has been developed for the separation and quantification of these derivatives.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 144
    ISSN: 1612-1112
    Keywords: Column liquid chromatography ; Oxygen radicals ; Nucleotides ; Aldehydes
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary The analysis of two metabolite groups, nucleotides and aldehydes, is necessary for assessment of oxygen radical metabolism during hypoxia and reoxygenation. Nucleotides and their derivatives were determined by HPLC using gradient elution with 10 mM NH4H2PO4 buffer containing 2 mM t-butylammoniumphosphate and acetonitrile. Aldehydes occuring after lipid peroxidation were analyzed by derivatisation to dinitrophenylhydrazones followed by TLC and HPLC separation with methanol/water on an ODS column.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 145
    Electronic Resource
    Electronic Resource
    Springer
    Chromatographia 28 (1989), S. 209-211 
    ISSN: 1612-1112
    Keywords: Column liquid chromatography ; Triazine herbicides
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary A number of 11 triazine herbicides and 7 of their corresponding metabolites were separated in a single HPLC run. The separation was achieved on a reversed-phase column using gradient elution with acetonitrile/buffer. Detection was by UV absorption at a wave-length of 220 nm.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 146
    ISSN: 1612-1112
    Keywords: Column liquid chromatography ; Solid phase extraction ; Polycyclic aromatic hydrocarbons ; Diode array and fluorescence detection
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary Both the separation of polycyclic aromatic hydrocarbons (PAH's) on tailor made HPLC phases, and their chromatographic enrichment and quantitative determination are of great interest. Because of the generally low concentrations of PAH's in the environment, and the low limiting values in German legislation for drinking water, methods for selective enrichment and sensitive detection are indispensable. On account of their relatively high amounts in soil, the determination of PAH's is valuable for the assessment of the potential danger to ground water by waste materials. These requirements can be fulfilled by used of solid phase extraction on enrichment columns, and fluorescence or UV/VIS diode array detection. For the detection of PAH's in the picogram range, the wavelengths for excitation and emission were time programmed over the chromatogram. With this feature, it is possible to detect all the individual compounds at the highest sensitivity, over the entire analysis.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 147
    Electronic Resource
    Electronic Resource
    Springer
    Chromatographia 28 (1989), S. 289-292 
    ISSN: 1612-1112
    Keywords: Column liquid chromatography ; Micro-bore and capillary columns ; Gradient techniques
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary A gradient delivery system for microbore and open tubular liquid chromatography is described. A gradient mixing vessel of 5–100μl, or 25–1000μl allows the generation of binary gradients with high reproducibility. The suitability of the system for short packed micro bore columns and open tubular columns is demonstrated.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 148
    ISSN: 1612-1112
    Keywords: Column liquid chromatography ; Flecainide in plasma ; Fluorescence detection
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary A high performance liquid chromatographic method for the determination of flecainide in serum has been developed. The analysis is performed on a microparticulate silica column. The eluate is monitored by fluorescence detection at an excitation wavelength of 300nm and an emission wavelength of 370nm. No sources of interference were identified and a coefficient of variation of less than 8% was observed on repeated flecainide determinations. The method has a good reproducibility, specificity and accuracy, and can be applied in therapeutic drug monitoring of flecainide in patients.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 149
    ISSN: 1612-1112
    Keywords: Column liquid chromatography ; Coulometric electrochemical detection ; Methylnaltrexone ; Rat brain and serum analysis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary A simple and sensitive method is described for the determination of methylaltrexone, a quaternary narcotic antagonist, in discrete rat brain regions and serum. Separation and quantitation are performed by reversedphase high-performance liquid chromatography with coulometric electrochemical detection. Perchloric acid extracts of the brain tissue or serum were passed through a normal-phase solid-phase extraction CN column, and methylnaltreexone was subsequently eluted with a mixture of absolute ethanol and 25mM trifluoroacetic acid. Methylnaltrexone gave a linear response over the range of 12.5–100ng in 1.0ml for cerebellar homogenates and 25–200ng in 50μl for serum. The average betweenassay coefficients of variation for methylnaltrexone from 1.0ml of cerebellar homogenate and 50μl of serum were 5.2 and 3.6%, respectively, over the concentration range studied. The within-assay coefficients of variation at 12.5ng/ml cerebellar homogenate and 25ng/50μl for serum were 7.4 and 4.6%, respectively. Analytical recovery of methylanyltrexone, added to cerebellar homogenate and serum samples, were 85 and 89%, respectively. The method was applied to the analysis of methylnaltrexone in discrete rat brain regions and serum after intraperitoneal injection.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 150
    Electronic Resource
    Electronic Resource
    Springer
    Chromatographia 28 (1989), S. 129-132 
    ISSN: 1612-1112
    Keywords: Column liquid chromatography ; Carotenoids ; Paprika, Rose hips, Marigold
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary A method is described for the preparative HPLC of carotenoids and carotenoid esters using a self-packing axially-compressed column. The reversed-phase system used employs an RP-18 stationary phase and a mobile phase consisting of a mixture of petroleum spirit, acetonitrile, methanol and tetrahydrofuran. The method is demonstrated for paprika fruit, rose hips and marigold flowers.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 151
    ISSN: 1612-1112
    Keywords: Column liquid chromatography ; Wheat proteins ; γ-gliadins ; Effect of pH on separation ; Effect of organic modifier on separation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary Reversed-phase, high-pressure liquid chromatography has been used to separate similar protein (γ-gliadin) components from 70% ethanol extracts of endosperm flour from two different accessions of the diploid wheatTriticum monococcum L. The effect of acetonitrile as the organic eluent was compared to acetonitrile: 2-propanol (3:1) at two different pH's. Conditions for maximum resolution of the γ-gliadin components were found to be at pH 7.2 with acetonitrile: 2-propanol (3:1) as the eluent. These conditions allowed the components to be obtained in sufficient purity for further charaterization.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 152
    ISSN: 1612-1112
    Keywords: Column liquid chromatography ; Ligand-exchange ; Preparative racemate resolution ; Amino-acids
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary Preparative resolutions of racemic amino-acids by ligand-exchange chromatography are described. Base-line resolution of multigram quantities of many racemic solutes was obtained using very simple equipment (open tubular column).
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 153
    Electronic Resource
    Electronic Resource
    Springer
    Chromatographia 28 (1989), S. 354-358 
    ISSN: 1612-1112
    Keywords: Column liquid chromatography ; Ternary mobile phases ; Solute retention model
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary In our previous publications we have established a new physico-chemically grounded retention model valid for the adsorption and partition mechanism of retention using multicomponent mobile phases. Moreover, we have demonstrated its practical usefulness for predicting solute retention in several different chromatographic modes (i.e. in TLC, normal-phase and reversed-phase HPLC) employing binary mobile phases. In this paper we give an ultimate check to the physicochemical correctness of our new retention model, using it for the description of solute retention in reversedphase HPLC systems with ternary mobile phases of the B+AB1+AB2 type. The complexity of these mobile phases and of the possible intermolecular interactions among the consitituent solvents was supposed to rigidly scrutinize the premises of the assumed new approach. We have observed a good agreement between the experimental retention parameter for a number of solutes chromatographed with the use of two different mobile phases of the B+AB1+AB2 type, and the retention parameter calculated according to the assumed model. Therefore, we believe to have sufficiently tested our new approach and confirmed its physico-chemical correctness.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 154
    ISSN: 1612-1112
    Keywords: Column liquid chromatography ; Optical resolution ; Polymeric adsorbents ; Penicillin sulfoxide ; Substituent effect
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary Fourteen new vinyl polymers carrying penicillin sulfoxide nucleus, poly (substituted-benzyl 1-oxo-6-metha-crylaminopenicillanate)s, were synthesized in order to investigate the influence of the substituents on the optical resolution capabilities. The resolution efficiency of the high-performance liquid chromatography columns comprising the obtained polymers were examined usingtrans-stilbene oxide and N-acetyl-1-phenethyl-amine. It was found that some columns resolved both racemates, some one, while the others did not separate either. A polymer which has 2,6-dichlorobenzyl moiety was found to resolve both racemates more effectively than the unsubstituted polymer.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 155
    Electronic Resource
    Electronic Resource
    Springer
    Chromatographia 28 (1989), S. 465-468 
    ISSN: 1612-1112
    Keywords: Column liquid chromatography ; Chlorinated phenols ; 4-Aminoantipyrine derivatives of phenols ; Metabolites of phenoxy alkanoic acid herbicides
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary High performance liquid chromatography (HPLC) has been applied to the separation and determination of o-chlorophenol, 2,4-dichlorophenol, 3,4-dichlorophenol, 2,5-dichlorophenol, and 2,4,5-trichlorophenol in water samples after prior derivatization with 4-aminoantipyrine. These substances are the phenolic decomposition products of the phenoxy-alkanoic acid herbicides: 2,4-dichlorophenoxyacetic acid (2,4-D), 2,4-dichlorophenoxybutyric acid (2,4-DB), and 2,4,5-trichlorophenoxyacetic acid (2,4,5-T). An RP-C18 column was used, with gradient elution starting at 50/50 and changing to 70/30 methanol/water (v/v) after 24 min. Detection was carried out at 470 nm where the 4-aminoantipyrilquinonimine derivatives show maximum absorbance. The method was linear over a concentration range of 5–10,000 ppb phenol in the original water sample. By using an enrichment step a detection limit of 2 ppb phenol could be approached. The method was used to study the degree of degradation of the phenoxy acids to phenols under different conditions of temperature, pH, and UV irradiation.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 156
    ISSN: 1612-1112
    Keywords: Column liquid chromatography ; Ligand exchange ; Chiral phase ; Optical resolution of 2-hydroxy acids
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary Using an MCl GEL CRS10W column, which was packed with octadecyl silica (ODS) coated with N,N-dioctyl-L-alanine, optical resolution of 2-hydroxy acids was performed. The optical resolution of mandelic acid derivatives and C2 to C5 2-hydroxy acids was carried without any pretreatment. The MCl GEL CRS10W column could resolve amino acids and 2-hydroxy acids. For their selective detection, a post-column method was employed in which the specific color reaction of 2-hydroxy acids with iron(III) ion was utilized. For the analysis of foodstuffs, in which amino acids and 2-hydroxy acids often coexist, the present method was found to be effective in distinguishing between these enantiomers.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 157
    Electronic Resource
    Electronic Resource
    Springer
    Chromatographia 28 (1989), S. 497-501 
    ISSN: 1612-1112
    Keywords: Column liquid chromatography ; Collagen metabolites ; Amino acid derivatives ; Glycosides
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary Methods are described for the isolation of galactosyl hydroxylysine and glucosylgalactosyl hydroxylysine from collagen and for the quantitative analysis of these hydroxylysine glycosides. The isolation procedure, based upon gel filtration and preparative ionpaired reversed-phase high-performance liquid chromatography, is simple and rapid in comparison with existing methods, allowing the production of tens of milligrams of each glycoside in a single day. Quantitative analysis of the hydroxylysine glycosides is effected by reversed-phase high-performance liquid chromatography with precolumn derivatization (usingo-phthal-dialdehyde) and fluorescence detection.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 158
    ISSN: 1612-1112
    Keywords: Column liquid chromatography ; Optical resolution ; Polymeric adsorbents ; Penicillin sulfoxide ; Copolymerization
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary A methacrylamide carrying penicillin sulfoxide skeleton, benzyl 1-oxo-6-methacrylaminopenicillanate, was copolymerized with methyl methacrylate. The optical resolution efficiency of the columns comprising the obtained copolymers was investigated using a high-performance liquid chromatography system. A copolymer incorporated by 27mol% of methyl methacrylate showed higher chirality recognition capability than the homopolymer, which suggests that the introduction of methyl methacrylate contributes to enriching desired penicillin sulfoxide alignment (i. e., tracticity) along the polymer main chain. An estimated penicillin monomer's number-average sequence length in the copolymer was 2.7.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 159
    Electronic Resource
    Electronic Resource
    Springer
    Chromatographia 28 (1989), S. 519-522 
    ISSN: 1612-1112
    Keywords: Column liquid chromatography ; Reversed-phase chromatography ; Separation of metal acetylacetonates
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary Using reversed-phase high-performance liquid chromatography acetylacetonate complexes with trivalent metals such as Al(III), Co(III), Cr(III) and Fe(III) have been examined in columns containing RP-2, RP-8 and RP-18 bonded phases. The mobile phase consisted of acetonitrile/water or methanol/water mixtures with various compositions. As shown the order of elution of the acetylacetonates depends on the type of the column packing and on the nature and concentration of the organic modifier in the mobile phase.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 160
    ISSN: 1612-1112
    Keywords: Column liquid chromatography ; Thin-layer chromatography ; Penstemide and serrulatoloside
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary Penstemide and serrulatoloside, two iridoids of similar molecular structure, were separated by stepwise gradient TLC in a straight-phase systems (silica-ethyl acetate+isopropanol) and by HPLC in a reversed-phase system (ODS-silica — water+methanol).
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 161
    ISSN: 1612-1112
    Keywords: Column liquid chromatography ; Overpressured layer chromatography ; Furocoumarin isomers ; Preparative separation of plant extracts
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary Preparative medium pressure liquid chromatography and semi-preparative high performance liquid chromatography on silica were employed for the isolation of eight furocoumarin isomers (iso-bergapten, angelicin, psoralen, bergapten, pimpinellin, sphondin, xanthotoxin and isopimpinellin). The conditions were transposed from analytical on-line overpressured layer chromatography and analytical high performance liquid chromatography, respectively. The retention data of the analytical on-line overpressured layer chromatographic separation and the preparative medium pressure liquid chromatographic isolation show a linear relationship. Using 15 μm TLC silica 60 as stationary phase a dry-packing procedure aas developed for labomatic medium pressure liquid chromatographic glass columns. The efficiency of the preparative separation techniques was demonstrated by the isolation of the investigated furocoumarins from Heraclei mantegazziani radix and from Pimpinellae radix (Balkan quality).
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 162
    Electronic Resource
    Electronic Resource
    Springer
    Chromatographia 27 (1989), S. 101-104 
    ISSN: 1612-1112
    Keywords: Column liquid chromatography ; Bromo/iodosubstituted thyronines ; Mobile phase optimization ; Radioimmunoassay detection
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary A reversed-phase high performance liquid chromatographic method on C-18 bonded silica is described for the separation of trisubstituted iodo/bromothyronines, which exert thyroid hormone activity. The composition of the mobile phase has been systematically optimized resulting in a ternary mixture of methanol/acetonitrile/water acidified with trifluoroacetic acid. The applicability of ultraviolet absorption detection, amperometric detection and off-line radioimmunoassay was investigated. The latter method allows detection of the different iodo/bromothyronines down to 40–120 ng/l mobile phase; this sensitivity is high enough for application to thyroid hydrolysates in order to clarify the question as to whether bromine can substitute iodine in the biosynthesis of thyroid hormones.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 163
    Electronic Resource
    Electronic Resource
    Springer
    Chromatographia 27 (1989), S. 113-117 
    ISSN: 1612-1112
    Keywords: Column liquid chromatography ; Retention contribution of nitrogen ; Effect on methylene and sulphur chains
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary The reaction of secondary amines R2NH with disulfur dichloride S2Cl2 in dichloro methane yields mixtures of bis-dialkylamino polysulphides R2N−Sn−NR2 with sulphur chain lengths varying from ns=2 to 14. The S chains are believed to be non-branched. The compounds form homologous series in each of which sulphur atoms give a constant contribution to retention. The sulphur retention index depends slightly on the carbon number in the terminal alkyl groups R. The presence of nitrogen lowers retention. The index increment of N is ca. −160 units, which is distinctly less negative than values found in alkylamines.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 164
    ISSN: 1612-1112
    Keywords: Column liquid chromatography ; Size-exclusion chromatography ; Fast atom bombardment-MS ; Peptic haemoglobin hydrolysate
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary A method is described for the ready identification of any peptide isolated from a complex peptic haemoglobin hydrolysate produced on the pilot-plant scale. A combination of size exclusion and reversed-phase, high-performance liquid chromatography have proved to be a useful strategy for fractionation of such a mixture. This technique enabled pure peptides from the total hydrolysate to be obtained. Amino acid analysis and fast atom bombardment mass spectrometry provided the accurate composition and molecular weight of any isolated peptide. Molecular weights are compared with those deduced from size-exclusion chromatography (SEC) and the usefulness of SEC is discussed. The procedure described in this study will be useful for acquiring a better knowledge of such an hydrolysate and could be extended to other crude protein digests.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 165
    ISSN: 1612-1112
    Keywords: Column liquid chromatography ; Electrochemical detector ; Amines ; Silages ; Feedstuffs
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary The use of the electrochemical detector (EC) in the high performance liquid chromatography (HPLC) of dansyl derivatives of biogenic amines is reported. Isocratic and gradient elution patterns of synthetic mixtures of putrescine, cadaverine, 1,6-diaminohexane, tryptamine, histamine, tyramine, spermine and spermidine on a reversed phase column are shown. Hydrodynamic voltammograms of standard compounds are presented. The detection limits of the EC are compared with those of ultraviolet and spectrofluorimetric detectors. A chromatographic profile of amines from the proteolytic catabolism of maize silage byClostridia is shown.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 166
    ISSN: 1612-1112
    Keywords: Column liquid chromatography ; Normal phase elution ; Silica and cyano columns ; Flavonoid compounds
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary HPLC retention data for a number of flavonoid compounds have been evaluated on normal phase silica and cyano colums according to the Soczewinski-Snyder (S.-S.) model. On the silica phase most of the flavones examined exhibited asymetrical peak shapes indicating strong and mixed retention mechanisms; on the cyano phase the intercept of the S.-S. relationship was independent of any hydroxy substitution pattern or of molecular planarity. A similar behaviour, but with different intercept values, was observed with coumarin and quinone compounds.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 167
    Electronic Resource
    Electronic Resource
    Springer
    Chromatographia 27 (1989), S. 292-296 
    ISSN: 1612-1112
    Keywords: Column liquid chromatography ; Selenium(IV)-tellurium(IV) separation ; Flow-through coulometric detector
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary The chromatographic behaviour of selenium and tellurium has been investigated with two different reversed-phase chromatographic methods, using P-350 (methyl-bi-isooctyl phosphate) and TBP (tributyl phosphate) as the stationary phases. HCl, HBr, NaCl and NaBr were employed as mobile phase components in both methods. The results suggested that the separation mechanism corresponds to the formation of TeCl (or TeBr) and P-350H (or TBPH) ion associate. A coulometric flow-through detector was applied to determine Se(IV) and Te(IV). Complete separation and quantitative determination of Se and Te could be achieved in 10 minutes.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 168
    Electronic Resource
    Electronic Resource
    Springer
    Chromatographia 27 (1989), S. 325-327 
    ISSN: 1612-1112
    Keywords: Column liquid chromatography ; Carotenoid ; Xanthophyll ; Broccoli ; Paprika
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary A method is described for the preparative HPLC of up to 50mg of carotenoid using a self-packing axially-compressed column. Oxygenated carotenoids, xanthophylls, are separated with silica as the stationary phase and acetone/petroleum ether as the mobile phase, while carotenes are separated using magnesium oxide/polyamide as the stationary phase and undiluted petroleum ether as the mobile phase.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 169
    Electronic Resource
    Electronic Resource
    Springer
    Chromatographia 27 (1989), S. 340-342 
    ISSN: 1612-1112
    Keywords: Column liquid chromatography ; Evaporative light scattering detection ; α, ω-Dicarboxylic and hydroxycarboxylic acids ; Alkylglucosides and glycerides
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary The advantages of an evaporative light scattering detector in HPLC are demonstrated using the separation of α, ω-dicarboxylic and hydroxycarboxylic acids, alkyl glucosides and mono-, di- and triglycerides as examples. By using this detector reversed phase as well as normal phase gradient HPLC becomes possible for substances with no UV absorption.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 170
    Electronic Resource
    Electronic Resource
    Springer
    Chromatographia 27 (1989), S. 371-377 
    ISSN: 1612-1112
    Keywords: Column liquid chromatography ; Alkyl-bonded silica gel ; Enthalpy ; Van der Waals volume
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary Starting from silica gel with a purity of 99.999%, octadecyl-(ODS), octyl-(C8) and propyl-(C3) bonded silica gels were synthesized, and end-capped by trimethyl groups. The pore size was 150 Å and the specific surface area was 320 m2/g. The ODS and C8 silica gels were stable in both acidic and basic solutions. The selectivity of these bonded-silica gels was examined from the difference of the retention behavior of alkanes (Al−Al), alkylbenzenes (Ph−Al), alkylalcohols (Al−OH) and polyaromatic hydrocarbons (PAH) in aqueous acetonitrile. On these packings the log k′ values decreased in the order Al−Al〉Ph−Al〉PAH〉Al−OH. Furthermore, the chromatographic behavior of these compounds was measured on polymer-coated octadecyl-bonded silica gel (CAP) and octadecyl-bonded vinyl alcohol copolymer gel (ODP). The selectivity was verified from the value of R* of these compounds: $$R = R_v + R^* $$ where R is the retention time, and Rv is the retention time of an alkane having the same Van der Waals volume as the analyte. The R* values indicated that this ODS had more selectivity than C8 and C3, however R* on C8 showed a very good correlation with R* on C3. Their retention behavior on CAP was similar to that of ODS, however, their capacity ratios measured on CAP were smaller than those on ODS. The ODP has selectivity for the retention of aromatic compounds, because PAHs were retained strongly on this column.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 171
    ISSN: 1612-1112
    Keywords: Column liquid chromatography ; Alternaria mycotoxins ; Food analysis ; Electrochemical detection
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary The electroactivity of majorAlternaria mycotoxins has been explored in order to devise a liquid chromatographic-electrochemical detection (LC-EC) method for the determination of these toxic metabolites in fungal cultures and in naturally contaminated foodstuffs. Alternariol, alternariol methyl ether, altertoxin-I and altertoxin-II have been found to be electroactive and could be detected at sub-nanogram levels. Advantages and limitations of dual electrode (screen mode) coulometric detection and single electrode amperometric detection are presented and discussed. The feasibility of electrochemical detection in gradient elution liquid chromatography as well as its applicability to the analysis of contaminated foodstuffs is demonstrated.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 172
    Electronic Resource
    Electronic Resource
    Springer
    Chromatographia 27 (1989), S. 431-435 
    ISSN: 1612-1112
    Keywords: Column liquid chromatography ; UV diode array detection ; Electro chemical detection ; Herbicides
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary An automated procedure is described for simultaneous UV detection at three different wavelengths and electro chemical detection in series of some residual herbicides. UV spectra of nine compounds of different compound groups are presented. Liquid-liquid extraction with dichloromethane and an enrichment of about one thousandfold has been used. Recovery rates after enrichment and detection limits of four s-triazine, three phenyl urea herbicides, metazachlore and metamitrone in river and drinking water are shown. It is concluded that the herbicides examined can be detected at levels between 10ng l−1 and 50ngl−1, without the necessity of derivatisation or clean-up processes.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 173
    Electronic Resource
    Electronic Resource
    Springer
    Chromatographia 27 (1989), S. 257-263 
    ISSN: 1612-1112
    Keywords: Column liquid chromatography ; Size exclusion ; Fractal dimension ; Retention model
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary Some porous packings used in chromatography have been claimed to be fractals with a scale of sizes a〈l〈L, where a is a molecular size and L is the size of the largest pores. For a fractal porous packing, the excluded volume for molecules in solution in the vicinity of the packing surface is directly related to Df, the fractal dimension of the pore surface (2〈Df〈3). Since retention in size exclusion chromatography is itself directly related to this excluded volume, the fractal nature of the packing provides a model of retention in this technique. According to this model there is a linear relationship between log Rs and log(1-Kd), where Rs is the hydrodynamic radius of the solute macromolecules and Kd the distribution coefficient. The fractal dimension is derived from the slope of this plot. Size exclusion chromatographic retention data have been analyzed according to the model. It is found that some HPLC packings are fractals with fractal dimensions ranging from about 2.15 to 2.6, depending on the material. Such a large range of Df values indicates large variations in the selectivities and domains of applications of the different packings. For some classical gel filtration chromatographic gels, the fractal retention model does not seem to apply.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 174
    ISSN: 1612-1112
    Keywords: Column liquid chromatography ; Micro-columns ; Flow rate and temperature programming ; PTH amino acid derivatives
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary The separation of phenylthiohydantoin (PTH) amino acid derivatives by flow rate and temperature programming in reversed-phase micro-column liquid chromatography (LC) has been investigated. For both programming modes a microcomputer-assisted retention prediction system (REPRES) was constructed. The performance of this system has been evaluated by comparing actually measured retention data to those predicted. Excellent agreements between those data were found. It is clearly indicated that simultaneous flow rate and temperature programming can improve the separation of PTH-amino acids in reduced analysis time.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 175
    Electronic Resource
    Electronic Resource
    Springer
    Chromatographia 28 (1989), S. 89-91 
    ISSN: 1612-1112
    Keywords: Column liquid chromatography ; Electrophoresis ; Comparison of HPLC and electrophoresis ; Proteins, peptides and amino acids
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary Protein structure analysis is an indispensible tool in modern biological research. However, the isolation of a protein or the separation of peptides in a form suitable for sequence analysis is a considerable technical challenge. The two predominant separation methods in protein biochemistry are chromatography and electrophoresis. In this paper the position, advantaged and disadvantages of both HPLC and electrophoresis for the separation of amino acids, peptides and proteins in protein structure analysis are discussed.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 176
    Electronic Resource
    Electronic Resource
    Springer
    Chromatographia 28 (1989), S. 565-568 
    ISSN: 1612-1112
    Keywords: Column liquid chromatography ; New bonded phases ; Alumina ; Protein separation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary Several reactions are tested for the chemical modification of alumina. These include the following: chlorination of the surface hydroxyls followed by reaction with an organolithium compound; chlorination of the surface hydroxyls followed by reaction with a Grignard reagent; chlorination of the surface hydroxyls followed by reaction with an amine; chlorination of the surface hydroxyls followed by reaction with an alcohol; direct reaction of the alumina with an organochloroalane and direct reaction of the alumina with an alcohol. Only the first reaction gave a product which contained enough bonded organic material to be easily detected by FTIR. Preliminary stability tests show that the product of the first reaction retains the bonded organic material when exposed to nonpolar and polar organic solvents as well as aqueous solutions of pH 1.0, 7.0 and 12.0. Chromatographic testing establishes reversed-phase behavior for alkylarylketones as solutes and the bonded phase displays good biocompatibility for a series of protein standards.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 177
    ISSN: 1612-1112
    Keywords: Column liquid chromatography ; Adenosine phosphates ; Adenosine phosphate degradation products ; Innervated frog muscle
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary Adenosine mono-, di- and triphosphates, inosine monophosphates, adenosine, inosine and hypoxanthine were separated in a single run by high-performance liquid chromatography with UV detection. AC-18 reversephase column was used. An isocratic elution with 100mM phosphate buffer (KH2PO4) pH6.5 and 1.2% methanol, followed by a 5 minute linear gradient up to 15% methanol after the 10th minute was performed during each run with a flow rate of 1.25ml/min. The time required for each analysis was 25 minutes. The detection limit for each substance ranged from 3 to 5 pmol. All the substances under study were detected in the incubation medium when adenosine triphosphate was exogenously applied to the innervated frog sartorius muscle.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 178
    ISSN: 1612-1112
    Keywords: Column liquid chromatography ; Molecular interactions ; Association effects ; Analyte solvation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary The linear Jaroniec equation has been utilized for the description of chromatographic systems in which the test substance molecule is solvated by the solvent molecules. A possibility of the formation of multimolecular solvates in the bulk phase has been confirmed. The measurements were made using liquid adsorption chromatography with ternary mobile phase.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 179
    ISSN: 1612-1112
    Keywords: Column liquid chromatography ; Chiral separations ; Trypsin on silica ; Amino acids
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary A new HPLC stationary phase was synthesized by the covalent immobilization of the enzyme trypsin (TRYP) on silica. The hydrolytic activity of the immobilized enzyme was 72% of the activity of an equivalent molar amount of free TRYP. The initial chromatographic studies indicate that this phase can be used for chiral separations of enantiomeric O- and N,O-derivatized amino acids which are natural substrates on TRYP and that the stereochemical resolutions are a result of the activity of the enzyme.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 180
    Electronic Resource
    Electronic Resource
    Springer
    Chromatographia 28 (1989), S. 574-578 
    ISSN: 1612-1112
    Keywords: Column liquid chromatography ; Chemically bonded phases ; End-capping ; Destructive effects on bonded phases
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary Hexamethyldisilazane (HMDS) and trimethylchlorosilane (TMS) have been used as a secondary deactivation (end-capping) reagents for packing materials for RP HPLC. Three types of chemically bonded phases (CBP) with different structures and different coverage densities were used. The destructive effects of HMDS on the coverage density of chemically bonded C18 and C8 phases is discussed.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 181
    ISSN: 1612-1112
    Keywords: Column liquid chromatography ; Cellulose acetate ; Acetyl content ; Temperature effects
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary Cellulose and cellulose mono-, di-, and triacetate were used as stationary phases for liquid chromatography with water as a mobile phase, and the retention behavior of alcohols, ethers, ketones, and chlorides was examined. For cellulose acetate columns, the logarithm of the specific retention volume, (logV g * ), correlated linearly with the logarithm of partition coefficient between 1-octanol and water (log Ko/w), for each homologous group, but all solutes were unretained on cellulose columns. With the exception of chlorides, the intercept values of the log V g * –log Ko/w regression lines increased significantly with increase of acetyl content of cellulose acetates, but the slopes of the regression lines changed little. This suggests that hydrophobic interaction between the acetyl groups of cellulose acetates and the alkyl chains of the solutes is the dominant factor in the retention. The capacity factors for 1-alcohols with cellulos diacetate column indicated a maximum at a column temperature of about 40°C. This unique retention behavior was assumed to be caused by small structural change of the cellulose acetate polymer, because this temperature effect on the retention corresponded with effects observed by differential scanning calorimetry (DSC).
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 182
    Electronic Resource
    Electronic Resource
    Springer
    Chromatographia 28 (1989), S. 161-166 
    ISSN: 1612-1112
    Keywords: Thin-layer chromatography ; Column liquid chromatography ; Micropreparative separations ; Furocoumarins
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary Furocoumarins from extracts ofHeracleum genus fruits were separated using normal and reversed phase TLC and HPLC and isolated in the milligram scale using overloaded systems of column chromatography. Binary or ternary solvents containing a polar modifier (methanol, diisopropyl ether or acetonitrile) were used as the mobile phases.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 183
    ISSN: 1612-1112
    Keywords: Column liquid chromatography ; Anion-exchange ; Mobile phase optimisation ; Egg-white proteins
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary Factors influencing the capacity of Whatman QA52 anion-exchange cellulose for hen egg-white proteins have been investigated. While simply increasing the concentration of protein in the feedstock increases the loading there is a concomitant reduction in binding efficiency in a single pass through the column. Substitution of buffer by water in the mobile phase during sample preparation, thereby reducing the ionic strength of the feedstock, had the effect of significantly increasing protein capacity whilst improving binding efficiency. During column loading large changes in pH of the mobile phase were observed although this had no apparent effect on the chromatography for this system.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 184
    Electronic Resource
    Electronic Resource
    Springer
    Chromatographia 28 (1989), S. 193-196 
    ISSN: 1612-1112
    Keywords: Column liquid chromatography ; Chiral stationary phases ; Immobilized enzymes ; Racemic resolution of amino acid esters
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary Racemic resolution of aromatic and aliphatic amino acid esters into L-amino acid and D-amino acid ester via LC and HPLC is achieved by using enzyme reactors as chromatographic columns. For this purpose α-chymotrypsin and trypsin are immobilized on Eupergit C, Sepharose 4B and Lichrosorb-Diol.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 185
    ISSN: 1612-1112
    Keywords: Column liquid chromatography ; Bonded stationary phases ; Evaluation of the hydrophobicity of sorbents
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary The energy of interaction (∈0) between the methylene group and the surface of a sorbent is proposed for use in the quantitative evaluation of the hydrophobicity of a sorbent. A method was developed to determine the ∈0 parameter from chromatographic measurements using the investigated sorbent as the stationary phase and linear methylene-containing homologous series, e.g., alkanols, amino-alkanes, etc., as the test compounds. The effectiveness of this method is demonstrated by using, as examples, a series of bonded stationary phases and a series of cross-linked copolymeric sorbents differing in the concentration of the hydrophobic groups. The proposed method is compared with the Martin rule used extensively in the chromatography of oligomers.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 186
    ISSN: 1612-1112
    Keywords: Thin-layer chromatography ; Column liquid chromatography ; Mobile phase optimization ; HPTLC transposition to HPLC
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary A computer-assisted method is presented for mobile phase selection for the optimal separation of pesticides by HPTLC and HPLC. The system is based on a plot of solute retention value and separation criterion vs. binary mobile phase composition for graphic optimization. The result of HPTLC can be transposed to HPLC for optimal separation. The transposition equation is given.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 187
    Electronic Resource
    Electronic Resource
    Springer
    Chromatographia 28 (1989), S. 311-312 
    ISSN: 1612-1112
    Keywords: Column liquid chromatography ; Flavonoid glycosides ; Betula
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary The main flavonoid glycosides ofBetulae folium extracts (quercetin-3-glucuronide, myricetin-3-galactoside, hyperosid, quercetin-3-arabinoside and quercetin-3-rhamnoside) have been separated by isocratic elution on a C18 Aquapore RP-300 column. Elution was performed with 17% isopropanol at pH 6.2 confirming the validity of this eluent for the analysis of the flavonoid glycosides.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 188
    ISSN: 1612-1112
    Keywords: Column liquid chromatography ; Chiral stationary phase ; Resolution of amino acid derivatives ; Enantioseparation by HPLC
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary A chiral stationary phase for the separation of some D-and L-amino acid derivatives using a new resolving agent is described. The enantiomeric resolution was accomplished by normal phase high-performance liquid chromatography. The support was easily prepared by coating an epoxy polymer of L-valinamide on aminopropylsilanized macroporous silica. The influence of subambient temperatures on the enantioselectivity was also examined.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 189
    ISSN: 1612-1112
    Keywords: Column liquid chromatography ; Chiral recognition process ; Enantiomeric elution order ; Mobile phase modifiers
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary Three enantiomeric solutes, a sulphoxide, a piperidine derivative and a methyl ester have been chromatographed on an HPLC chiral stationary phase (CSP) based upon cellulose-tribenzoate (Chiralcel OB-CSP). The mobile phases used in the study were composed of hexane modified with homologous series of primary, secondary and cyclic alcohols. Interesting reversals in enantiomeric elution order have been observed for 2-phenoxypropanoic acid methyl ester associated with changes in chain length or ring size of the alcohol mobile phase modifier. The results of the study suggest that at least two chiral recognition mechanisms operate on the OB-CSP and point out the importance of acquiring elution order data in all studies involving chiral stationary phases.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 190
    ISSN: 1612-1112
    Keywords: Column liquid chromatography ; Prediction of retention times ; Gradient elution ; Substituted quinolines
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary A chromatographic model able to predict, from experimental isocratic data, retention times of solutes under gradient conditions has been proposed previously. The prediction was shown to be totally independent of the chemical properties of both solutes and eluents. In order to further check the general validity of the theory, the model has now been applied to a nonhomologous set of compounds, namely a range of substituted quinolines (methyl-, hydroxy- and amino-) and several different stationary phases. Results show a dependence on the stationary phase and, to a lesser extent, on the chemical structure of the solutes. The possible sources of errors are discussed. The generality of the method holds, within acceptable limits, if predictions concern the same type of stationary phase.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 191
    ISSN: 1612-1112
    Keywords: Column liquid chromatography ; Thiol analysis ; Fluorimetric detection ; Derivatization with 4-(6-methylnaphthalen-2-yl)-4-oxobuten-2-oic acid
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary The use of 4-(6-methylnaphthalen-2-yl)-4-oxobuten-2-oic acid as a fluorogenic reagent in pre-column derivatization for the high-performance liquid chromatography (HPLC) of biologically important thiols (L-cysteine, glutathione, N-acetylcysteine, homocysteine and mercaptopropionylglycine) was investigated. The aroylacrylic acid reacts selectively and rapidly (15 min. at room temperature) with the thiol compounds to give stable fluorescent adducts which can be separated by reversedphase HPLC and detected fluorometrically (λex 300nm); λem 445nm). The experimental conditions for the thiol derivatization and chromatographic separation are discussed. Applications to the determination of N-acetylcysteine, mercaptopropionylglycine and cysteine are described.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 192
    Electronic Resource
    Electronic Resource
    Springer
    Chromatographia 27 (1989), S. 194-200 
    ISSN: 1612-1112
    Keywords: Column liquid chromatography ; Dissociation constants ; Potentiometric titration ; 2,4-Dimethylthiazole ; Trimethylpyrazine ; Methyl anthranilate
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary Reversed-phase liquid chromatography on two stationary phases—octadecylbonded silica Partisil ODS-3 and polystyrene-divinylbenzene resin PRP-1—and potentiometric titration in the water/methanol mobile phase were investigated in order to determine the dissociation constants of three weakly basic aroma compounds, namely trimethyl pyrazine, 2,4-dimethyl thiazole and methyl anthranilate. The data obtained from both methods are quite consistent and compare favourably to values found in the literature.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 193
    ISSN: 1612-1112
    Keywords: Column liquid chromatography ; Cathinone metabolites ; Plasma
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary High-performance liquid chromatography (HPLC) for the determination of (−)-cathinone in rabbit and human plasma has been studied. The problem of dimerization during extraction from plasma was satisfactorily resolved. Detection was by UV at 257 nm. Concentration levels as low as 24 ng ml−1 were satisfactorily determined. This level of sensitivity should be adequate for the detection of (−)-cathinone in the blood of khat users and also for the quantitative determination of (−)-cathinone in blood for pharmacokinetic purposes. The applicability of the assay procedure to pharmacokinetic studies is demonstrated.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 194
    ISSN: 1612-1112
    Keywords: Column liquid chromatography ; Glucose, maltose and maltotriose ; α-Amylase and glucoamylase ; Microfungal cultures
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary In the hydrolysis of soluble starch by mixtures of α-amylase and glucoamylase, the ratios maltose/glucose and maltoriose/glucose linearly depend, over a wide range, on the relation between both enzymes and are independent on the activity level of the enzymatic preparation. HPLC determination of hydrolysis products (glucose, maltose and maltotriose) of soluble starch by mixtures of these enzymes, after incubation under controlled conditions, is a rapid method for the evaluation of the relative levels of each enzyme in the mixtures. The method, first developed using pure commercial amylases, is applied, with consistent results, to cell free media ofAspergillus niger cultures on a glycogen-rich effluent.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 195
    ISSN: 1612-1112
    Keywords: Column liquid chromatography ; Principal components analysis (PCA) ; Iterative target transformation factor analysis (ITTFA) ; Peak labelling ; Chromatographic peak deconvolution
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary The method of iterative target transformation factor analysis (ITTFA) used in conjunction with second derivative peak finding has shown to be a practical method for the peak deconvolution and reconstruction of HPLC chromatograms and spectra. The second derivative method of peak finding is acceptable for resolutions above 0.5 for peaks of similar heights. Above 0.5 resolution the labelling gives correct results where the spectra are substantially different and also when reasonably similar. Below this value the peak labelling was still accurate where the spectra were different. Solvent effects on the spectra of the compounds studied are small and do not hinder the peak labelling process. Thus small “local” libraries are feasible.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 196
    ISSN: 1612-1112
    Keywords: Column liquid chromatography ; Chlorophyll-bonded stationary phase ; Cyano(pheophytinato a)cobalt(III) ; Pheophytin a
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary The separation and determination of the nitrite ion by affinity chromatography is described. The good separation of the nitrite ion was obtained by using cyano-(pheophytinato a)cobalt(III) bonded octadecylsilica as the stationary phase and water of pH 4.3 adjusted by acetic acid as the mobile phase. Conventional ion chromatograph was also used for the analysis of the nitrite ion. For the synthetic samples prepared by mixing the nitrite and nitrate ions, analytical values obtained by affinity chromatography were in agreement with calculated values and close to the analytical values obtained by ion chromatography. In the proposed affinity chromatography, the nitrite and nitrate ions could be determined in the concentration range of 0.15–1.0ppm and 0.1–1.0ppm with relative standard deviations (n=10) of 5.3% and 4.7%, respectively.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 197
    Electronic Resource
    Electronic Resource
    Springer
    Chromatographia 28 (1989), S. 27-30 
    ISSN: 1612-1112
    Keywords: Column liquid chromatography ; Atmospheric ammonia ; m-Toluamide derivative ; Annular denuder
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary A simple and reliable method for routine measurement of ammonia in ambient air is described. It is based on the collection of ammonia on H3PO3-coated annular denuders and its subsequent derivatization withm-toluoyl chloride (MTC) in alkaline acetonitrile. The resultingm-toluamide is determined by reversed phase HPLC with UV detection at 230 nm. The limit of dotection is about 0.3μg m−3 for NH3 in air samples collected at 151 min−1 for one hour.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 198
    Electronic Resource
    Electronic Resource
    Springer
    Chromatographia 28 (1989), S. 39-44 
    ISSN: 1612-1112
    Keywords: Column liquid chromatography ; Thermus aquaticus ; Ribosome ; 50S and 30S subunit proteins ; Gel electrophoresis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary The ribosomal 50S and 30S subunit proteins (r-proteins) ofThermus aquaticus have, for the first time, been characterized by size exclusion chromatography (SEC) and by reversed phase high performance liquid chromatography (RPC). To ensure that the best resolution in the RPC was obtained. the elution conditions, such as gradient time, flow rate, temperature, ionic strength of the eluent and the type of stationary phase were optimized. Correlation between experimentally found retention times and those predicted by DryLab G was better than 0.7% over 30 peaks. Protein fractions from RPC runs were desalted and processed by gel electrophoresis so that the ribosomal proteins could be identified by their position on SDS-polyacrylamide gels. The enhanced speed and quality of separation which has been achieved in this study is expected to bring advantaces in experimental work with ribosomal proteins as well as with other biopolymers. In our case the high resolution technique provides a basis for the preparation of a collection of individual ribosomal protein components for future rRNA-protein interaction studies.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 199
    Electronic Resource
    Electronic Resource
    Springer
    Chromatographia 27 (1989), S. 321-324 
    ISSN: 1612-1112
    Keywords: Column liquid chromatography ; Simulation of peak profiles ; Rouchon model ; LEA model
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary The possibilities and domain of applicability of the ideal chromatography model for calculating peak profiles in non-linear chromatography are analyzed. For this purpose we used the main conclusion of the model of a layer of equilibrium adsorption (LEA model), which determines the difference between ideal and non-ideal chromatography in terms of the relative length of a chromatographic column. It is shown that the experimental data of non-linear high-performance liquid chromatography can be approximated in terms of the elementary analytical relations known in the theory of ideal chromatography.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 200
    Electronic Resource
    Electronic Resource
    Springer
    Chromatographia 27 (1989), S. 364-366 
    ISSN: 1612-1112
    Keywords: Column liquid chromatography ; Labetalol ; Separation of racemic diastereomers
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary A direct, isocratic, reversed phase HPLC procedure is developed for the separation of the diastereomeric racemates of labetalol, a combined α- and β-adrenoreceptor antagonist. The aminoalcohol-type diastereomers were resolved on a C18 column using methanolwater-25% ammonia 27-75-2 mobile phase and detection at 220nm. The procedure is simple and convenient to carry out. The method may be of use in the determination of the individual diastereomeric racemates of labetalol in different forms such as bulk substance, pharmaceutical dosage preparations and biological fluids.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...