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
  • Articles  (816)
  • Column liquid chromatography  (349)
  • healthy volunteers  (139)
  • Coleoptera  (131)
  • bioavailability  (82)
  • side-effects  (67)
  • calcium  (64)
  • Chemistry
  • Springer  (816)
  • 1985-1989  (816)
  • 1960-1964
  • 1950-1954
  • 1945-1949
  • Chemistry and Pharmacology  (816)
  • Political Science
  • Process Engineering, Biotechnology, Nutrition Technology
Collection
  • Articles  (816)
Keywords
Years
Year
Topic
  • 101
    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 ...
  • 102
    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 ...
  • 103
    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 ...
  • 104
    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 ...
  • 105
    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 ...
  • 106
    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 ...
  • 107
    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 ...
  • 108
    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 ...
  • 109
    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 ...
  • 110
    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 ...
  • 111
    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 ...
  • 112
    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 ...
  • 113
    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 ...
  • 114
    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 ...
  • 115
    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 ...
  • 116
    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 ...
  • 117
    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 ...
  • 118
    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 ...
  • 119
    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 ...
  • 120
    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 ...
  • 121
    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 ...
  • 122
    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 ...
  • 123
    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 ...
  • 124
    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 ...
  • 125
    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 ...
  • 126
    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 ...
  • 127
    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 ...
  • 128
    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 ...
  • 129
    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 ...
  • 130
    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 ...
  • 131
    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 ...
  • 132
    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 ...
  • 133
    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 ...
  • 134
    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 ...
  • 135
    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 ...
  • 136
    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 ...
  • 137
    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 ...
  • 138
    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 ...
  • 139
    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 ...
  • 140
    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 ...
  • 141
    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 ...
  • 142
    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 ...
  • 143
    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 ...
  • 144
    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 ...
  • 145
    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 ...
  • 146
    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 ...
  • 147
    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 ...
  • 148
    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 ...
  • 149
    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 ...
  • 150
    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 ...
  • 151
    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 ...
  • 152
    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 ...
  • 153
    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 ...
  • 154
    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 ...
  • 155
    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 ...
  • 156
    Electronic Resource
    Electronic Resource
    Springer
    Chromatographia 27 (1989), S. 378-384 
    ISSN: 1612-1112
    Keywords: Column liquid chromatography ; Reversed phases ; Retention and surface coverage ; Phase ratio
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary Members of three homologous series and five non-homologous solutes with various functional groups were chromatographed on a series of well-characterized C18 reversed stationary phases with a range of methanol-water mobile phases. Measured capacity factors of solutes were correlated with the concentration of C18 ligands on the stationary phase. A linear relationship with the slope depending on a solute molecular structure and the volume fraction of methanol in the mobile phase was obtained. A method for the evaluation of phase ratio is also proposed.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 157
    ISSN: 1612-1112
    Keywords: Column liquid chromatography ; Supercritical fluid chromatography ; Separation of steroids ; FTIR spectrometric detection
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary On-line FT-IR detection of a model mixture of steroids is performed for both SFC and HPLC. For HPLC, a conventional cyanopropyl bonded phase analytical-scale column and a highly crosslinked cyanopropyl microbore-scale column were used to separate the steroids. The latter, more deactivated column afforded no separation with the identical mobile phase. The SFC separation was carried out on crosslinked cyanopropyl bonded phase in a packed microbore column and 25% cyano-25% phenyl-50% methyl polysiloxane phase in a capillary column. It was seen that the order of elution of the steroids in both SFC and HPLC can be related to the number of hydroxyl groups present in the steroid molecule. On-line infrared spectra for each compound in both the liquid phase and the supercritical-fluid phase match well, with the carbonyl bands, slightly shifted to lower frequency in the liquid phase. Experiments are described which enable one to estimate the relative efficiency of various columns in several situations which are employed in this study.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 158
    Electronic Resource
    Electronic Resource
    Springer
    Chromatographia 27 (1989), S. 467-468 
    ISSN: 1612-1112
    Keywords: Column liquid chromatography ; Uric acid extraction ; Determination of uric acid
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary A method was developed for the determination of uric acid in the feces of egg-laying hens by high-performance liquid chromatography (HPLC), using a NovaPak C18 column and phosphate buffer as the mobile phase. Uric acid obtained by semi-preparative HPLC purification was used as the standard. Data on selectivity, sensitivity and precision demonstrate the reliability of this method.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 159
    ISSN: 1612-1112
    Keywords: Thin-layer chromatography ; Column liquid chromatography ; Dexamethasone related compounds ; Mass spectrometry ; Illicit drug formulations
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary A methodology for the analysis of dexamethasone and related compounds is proposed. Nine corticoids (corticosteroids) have been separated by TLC and by normalphase HPLC. The optimization of the HPLC separation is performed on a diol column and with a n-hexane/isopropanol (80:20) mobile phase. Mass spectrometry is used to elucidate the nature of the compounds isolated from illicit drug formulations and to confirm the structure of synthesised derivatives from the parent dexamethasone.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 160
    Electronic Resource
    Electronic Resource
    Springer
    Chromatographia 28 (1989), S. 126-128 
    ISSN: 1612-1112
    Keywords: Column liquid chromatography ; Preparative isolation ; (+)-Beta-eudesmol ; Amyris balsamifera
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary Optically pure (+)-beta-eudesmol is a possible starting material for the synthesis of several termite defense compounds. A two step procedure for the isolation of gram quantities of (+)-beta-eudesmol from commercially availableAmyris balsamifera oil (syn. West Indian sandalwood oil), containing 8% beta-eudesmol, was developed. Step one consisted of an efficient vacuum distillation of the total oil. Step two was a medium pressure LC separation with an AgNO3 impregnated silica gel stationary phase. Several other separation procedures failed due to the presence of many closely related sesquiterpene alcohols (75% of the oil).
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 161
    ISSN: 1612-1112
    Keywords: Column liquid chromatography ; Pressure effects ; System peaks ; Sorption equilibrium
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary Brief pressure changes take often place within a liquid chromatography column, e.g., during sample injection. It is shown that pressure jumps may cause local changes in the composition of a mixed effluent and the rise of system peaks in the chromatogram. This is a consequence of the dependence of sorption equilibrium on pressure.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 162
    Electronic Resource
    Electronic Resource
    Springer
    Chromatographia 28 (1989), S. 85-88 
    ISSN: 1612-1112
    Keywords: Column liquid chromatography ; Quality assurance ; Pharmaceutical analysis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary One possible method has been demonstrated for pharmaceutical quality control which is not restricted to this field and fulfils and documents the prerequisites for reliable, accurate and precise HPLC analysis. This includes validation which shows that the method is able in principle to fulfil the requirements, the apparatus test which shows that the apparatus generally works correctly and precisely and the system suitability test which shows that the method provides accurate and precise results on this apparatus and with this column for the analysis in question when other non-equipment and non-method-induced errors are excluded.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 163
    Electronic Resource
    Electronic Resource
    Springer
    Chromatographia 28 (1989), S. 183-188 
    ISSN: 1612-1112
    Keywords: Column liquid chromatography ; Triglycerides ; Gradient elution ; UV detector
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary A method of reserved-phase HPLC analysis for mixtures of triglycerides (TG's) that provides good resolution at acceptable analysis times for high-ECN TG's has been developed. An elution gradient of methyltert-butyl-ether (MTBE) in acetonitrile (ACN) was used with an ultraviolet detector operated at 215nm. The effect of the proportion of MTBE in the mobile phase, gradient time, temperature and sample solvent on TG retention and resolution was studied. Linear relationships were derived between the logarithm of the capacity factor (log k'), and the logarithm of selectivity (log α) and the above-mentioned chromatographic factors. The conditions selected were: an elution gradient of from 23 to 30% MTBE, an elution gradient time of 25 minutes, and a temperature of 30°C, which provided good resolution of soybean oil TG's in less than 30 minutes.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 164
    Electronic Resource
    Electronic Resource
    Springer
    Chromatographia 28 (1989), S. 197-202 
    ISSN: 1612-1112
    Keywords: Column liquid chromatography ; Thin layer chromatography ; Piroxicam ; Piroxicam degradation products
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary HPTLC densitometry and HPLC are considered for the simultaneous determination of the degradation products of piroxicam (2-aminopyridine, DP-I and DP-II). The substances were separated on silica gel with fluorescence indicator in ethylacetate — toluene — diethylamine (10∶10∶5) and toluene — absolute ethanol — glacial acetic acid (8∶1.2∶0.5) systems. The measuring absorbance (detection of reflectance) of the separated substances was carried out “in situ” at 296 nm using 4-level calibration (external standard, nonlinear regresson function) in the concentration range 600–1200 ng 2-aminopyridine/spot and 300–600 ng DP-I and DP-II/spot. The HPLC method was carried out using RP-8 stationary phase and methanol + phosphate-citrate buffer, pH 3 mobile phase with addition of sodium pentanesulfonate (40+60, v/v). 2-aminopyridine wass detected at 300 nm, DP-I at 280 nm and DP-II at 248 nm. The concentration range for 2-aminopyridine is 2–40 μg/ml, for DP-I and DP-II 2–20 μg/ml (for an injection volume of 10 μl). The results were evaluated by linear regression analysis.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 165
    ISSN: 1612-1112
    Keywords: Column liquid chromatography ; Chiral bonded phases ; Enantiomer separations ; Amino acid esters
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary N-Protected single amino acid residues have been chemically bound to aminopropylated silica gel to give chiral HPLC column packings. Surface coverages have been determined by both elemental and aminoacid analyses. In addition, the nature of the surface-bound groups has been studied by reflectance fourier transform infrared (FTIR) spectroscopy. The resolution of a range of racemic mixtures has been achieved using the column packings.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 166
    Electronic Resource
    Electronic Resource
    Springer
    Chromatographia 28 (1989), S. 263-266 
    ISSN: 1612-1112
    Keywords: Column liquid chromatography ; Triacetylcellulose ; Enantiomer interconversion ; Deconvolution of chromatograms
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary The enantiomers of 1,3,7-trimethylbenzo[c]phenanthrene, a chiral helicene hydrocarbon, are separated on triacetyl-cellulose but interconvert during HPLC. Column temperatures were between 2 and 22°C and linear velocities between 0.3 and 1.2 mm s−1. Simultaneous photometric and polarimetric detection resulted in deconvoluted experimental chromatograms, showing the relative concentration of each of the enantiomers as aseparate function of the retention volume. The use of deconvoluted chromatograms for determining rate constants of enantiomerization is discussed. It is of interest that the rate constant at 22.3°C in solution, i.e. in the absence of a sorbent, has been obtained by an independent method: stopped-flow monitoring of racemization after HPLC on triacetylcellulose.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 167
    ISSN: 1612-1112
    Keywords: Column liquid chromatography ; Synthetic tanning agents ; Correlation of composition and tanning properties
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary Gradient elution RP-HPLC has been applied to the separation of the constituents of synthetic tanning agents. Information obtained from the chromatographic results was used to assess the possibility of optimizing the conditions of synthesis, to find out the number of species formed and to make a start at correlating the composition of the tanning agents and their properties.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 168
    Electronic Resource
    Electronic Resource
    Springer
    Chromatographia 28 (1989), S. 307-310 
    ISSN: 1612-1112
    Keywords: Column liquid chromatography ; Plasma Catecholamines ; Dopamine ; Electrochemical detection
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary We describe here a sensitive, selective and rapid method to quantitate plasma catecholamines, especially dopamine, using high-performance liquid chromatography with electrochemical detection. This method requires a 10-minute run time and has a threshold for detection of 2 picograms, (10pg/ml). A number of commonly employed mobile phases for catecholamine analysis have been tested and have failed to detect dopamine in biological samples. Neither acetonitrile (3–7%) or methanol, (5–8%) in the mobile phase has produced consistently interpretable data either due to inability to detect or interference from co-eluting substances. Optimal detection was achieved with a mobile phase containing sodium acetate (6.8g), citric acid (5.9g), EDTA (48mg), di-n-butylamine (270μl), Na-1-octane sulfate (850mg), methanol (100 ml) (amounts refer to 1 liter aqueous solution) (pH 4.3). The mobile phase was passed through a Waters 5μ resolve C18 column using a Waters 590 pump and m460 electrochemical detector and 740 data module, Flow rate was 0.9ml/min. Using this method, normal values in human and swine left ventricular myocardium and human and swine plasma have been established for norepinephrine, epinephrine, and dopamine.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 169
    ISSN: 1612-1112
    Keywords: Column liquid chromatography ; Catecholamines in urine ; Liquid-solid extraction ; Metal-loaded silica
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary The use of iron loaded silica to selectively preconcentrate, by a chelating effect, catechol and its derivatives has been investigated. Parameters which can influence the breakthrough volume, such as minimum saturation concentration, variation of pH, ionic strength and flow rate of the preconcentrated phase are described. The coupling of this method with an ion-pairing chromatographic separation is demonstrated, several eluting solutions have been investigated. The influence of elution times, the linearity, the limit of detection and the recovery of the system are studied. This method has been applied to the quantitative determination of catecholamines in urine samples using 1,2-dihydroxybenzylamine as an internal standard.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 170
    ISSN: 1612-1112
    Keywords: Column liquid chromatography ; Optical resolution ; Polymeric adsorbents ; Penicillin sulfoxide
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary Polyacryl or methacrylamides bearing penicillin sulfoxide skeleton were synthesized. The obtained polymers were coated onto macroporous silica gel and the properties of the prepared packings were investigated. The column packing comprising poly(benzyl 1-oxo-6-methacrylaminopenicillanate) was found to resolve various aromatic racemates.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 171
    ISSN: 1612-1112
    Keywords: Column liquid chromatography ; Fluorimetric detection ; Adriamycin ; Adriamycinol ; Human plasma
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary A simple and very sensitive HPLC method, for the simultaneous determination in human plasma of adriamycin and its metabolite adriamycinol, is described. Plasmas from patients were stored frozen. Thawed samples were extracted by absorption of anthracyclin onto a small C18 column. After evaporation of the eluate and reconstitution of the residue with methanol (100μL), 30 to 40μL of the mixture were injected into the chromatograph. Separation was obtained using an RP 8 column with a mobile phase of formate buffermethanol-acetonitrile (50∶23∶27, v/v). A spectrofluorimeter was used as detector. The limit of sensitivity of the assay was 50 pcg/ml of plasma.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 172
    Electronic Resource
    Electronic Resource
    Springer
    Chromatographia 28 (1989), S. 405-411 
    ISSN: 1612-1112
    Keywords: Column liquid chromatography ; Gas chromatography ; Concentration of volatile flavor compounds ; ODS packing
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary Volatile flavor compounds in aqueous model systems, distillates of coffee extract and juices such as apple, tomato, pineapple and grape were adsorbed on an ODS column during HPLC and monitoring absorption at 280nm. The adsorbed volatile compounds were eluted with a small volume of ethanol. Volatile compounds in the eluates were concentrated 22 to 100 times those in the distillates. Recovery of compounds was 50–90%. Breakthrough of specific compounds such as γ-valerolactone, furfuryl acetate and t-2-hexenal in the model systems and several compounds in the juice distillates was detected by capillary GC. Pattern similarity calculated between the GC profiles of a juice distillate and the corresponding eluate gave a qualitative comparison. This novel and versatile method utilizing conventional RP-HPLC may be widely applicable for concentrating volatiles in aqueous systems, at levels from ppm to ppb.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 173
    ISSN: 1612-1112
    Keywords: Column liquid chromatography ; Carboxylic acids ; Fluoregenic esterification ; Phase-transfer catalysis ; Ion pairing ; N-(1-Pyrenyl)-bromoacetamide
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary N-(1-Pyrenyl)-bromoacetamide, which is readily synthesized from 1-aminopyrene and bromoacetyl bromide, has proved to be an excellent derivatization reagent for carboxylic acids. A technique has been developed, based upon a reaction with the carboxylate as an ion pair in ethylene dichloride at 90 °C, which gives highly fluorescent ester derivatives, permitting quantitative determination by liquid chromatography of less than one pmol using conventional fluorimetric detection. Further, the method is highly reproducible and of general utility.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 174
    Electronic Resource
    Electronic Resource
    Springer
    Chromatographia 28 (1989), S. 341-353 
    ISSN: 1612-1112
    Keywords: Column liquid chromatography ; Diode array detectors (DAD) ; Toxicology ; Automated solute identification
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary The possibilities and limitation of automated solute identification via UV/VIS spectroscopy in HPLC are demonstrated and applications in toxicologic analysis are described. A standard isocratic system is used. The influence of various chromatographic parameters on retention time is shown. A retention time window of ±15% is required. In addition to retention time, derived spectral data are calculated (minima and maxima of derivatives, area counts under standardized spectral ranges, absorption at various wavelength) and used for positive solute identification. It is possible to identify solutes with a high degree of certainty in urine and plasma if their concentration is at least 10 ppm.
    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. 370-374 
    ISSN: 1612-1112
    Keywords: Column liquid chromatography ; Diffusion coefficients ; Distribution coefficients ; Dextran
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary The chromatographic technique as a means for experimental studies of diffusion in porous solids has been demonstrated. In this paper we report the effective diffusion coefficients which we have chromatographically obtained for two dextran samples and three low molecular weight solutes. The chromatographic method of measuring diffusional resistances in porous solids has the advantages of rapidity and simplicity. This method also provides information on the axial dispersion and distribution of a solute between the moving phase and the solvent held stationary in the pore. The elution curves of a packed column in pulse response experiments were analyzed by the method of moments to give the parameters of interest. The results indicate that pore diffusion of the solutes was appreciably restricted in comparison with diffusion in bulk solution. The degree of hindrance depended on the size of the diffusing substances.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 176
    ISSN: 1612-1112
    Keywords: Column liquid chromatography ; Micelle-solute association constants ; Benzene and naphthalene derivatives
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary The interaction of some benzene and naphthalene derivatives with sodium dodecyl sulphate, hexadecyltrimethylmmonium bromide and polyoxyethylene [23] dodecanol micelles has been evaluated by high operformance liquid chromatography using micellar mobile phases. The micelle-solute association constants have been obtained for the compounds investigated. Good correlation between free energy of transfer for water-micelles and for octanol-water has been observed.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 177
    Electronic Resource
    Electronic Resource
    Springer
    Chromatographia 28 (1989), S. 412-414 
    ISSN: 1612-1112
    Keywords: Column liquid chromatography ; Dinitrobenzene isomers
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary An efficient, reproducible and rapid high-performance liquid chromatographic method, in normal phase mode, for the analysis of the three dinitrobenzene isomers is described. The method affords good linearity for each isomer in the range 10–160 μg ml−1. The total analysis time is only 10 minutes, and the method shows an accuracy of ±1.25% with a coefficient of variation from 0.30% to 2.85% for different levels of the dinitrobenzene isomers.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 178
    Electronic Resource
    Electronic Resource
    Springer
    Chromatographia 28 (1989), S. 493-496 
    ISSN: 1612-1112
    Keywords: Column liquid chromatography ; Nucleic acid components ; Buffer salt concentration ; Variation of retention
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary In the reversed-phase high-performance liquid chromatographic studies of nucleotides, nucleosides and bases, phosphate and acetate are commonly used as buffer materials. The concentration of these buffer salts in the mobile phase exerts noticeable influence both upon the retardation and upon the separation of the nucleic acid components. This can be of certain usage in the fine adjustment of the elution order of individual components. The possible reasons for the observed data are discussed.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 179
    ISSN: 1612-1112
    Keywords: Column liquid chromatography ; Optical resolution ; Polymeric adsorbents ; Penicillin sulfoxide ; Radical polymerization
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary Polymethacrylamide carrying penicillin sulfoxide skeleton, poly(benzyl 1-oxo-6-methacrylaminopenicillanate) was synthesized in various solvents. Optical resolution efficiency of the high-performance liquid chromatography columns comprising the polymers was investigated. It was found that the radical polymerization solvent influenced the optical resolution capability of the resultant polymer, and that less hydrogen-bonding solvent was preferred for effective resolution.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 180
    ISSN: 1573-904X
    Keywords: mean residence time ; moment analysis ; Michaelis–Menten elimination ; compartmental models ; bioavailability ; mean absorption time
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract Equations describing the mean residence time (MRT) of drugs in the body are derived for drugs that are administered by first-and zero-order rates into systems with Michaelis–Menten elimination. With computer simulations, the validity of these equations, the differences between them, and the conventional approach using the AUMC/AUC or the summation of mean times are demonstrated by examining calculations of the percentage of the administered dose eliminated at the MRT and AUMC/AUC. The effects of the absorption rate on the AUC and on the approximate and true MRT values in a nonlinear pharmacokinetic system are also illustrated with computer simulations. It was previously found that the true MRTiv = V ss · AUCiv/dose for an iv bolus. The total MRT (sum of input and disposition) of a drug after noninstantaneous administration was found to be a function of the MRTiv, two values of AUC (iv and non-iv), and exactly how the drug is administered expressed as the mean absorption time (MAT). In addition, a theoretical basis is proposed for calculation of the bioavailability of drugs in both linear and nonlinear pharmacokinetic systems.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 181
    ISSN: 1573-904X
    Keywords: bioavailability ; scintigraphy ; gastrointestinal transit ; controlled release ; phenylpropanolamine ; hydroxypropylmethylcellulose
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract Two controlled-release hydroxypropylmethylcellulose (HPMC) matrix formulations, a single-unit and a multiple-unit system, have been evaluated in human volunteers. Both formulations contained the sympathomimetic drug phenylpropanolamine hydrochloride and each was radiolabeled with 111Inbound Amberlite IR 120 ion-exchange resin. The formulations were administered to each of six healthy male volunteers and gastrointestinal (GI) transit was monitored using a gamma camera. Serum samples were taken at set time intervals and assayed for phenylpropanolamine content, thus allowing blood drug levels to be correlated with the position of the dosage form in the GI tract. The multiple-unit system emptied from the stomach gradually over a period of about 180 min, when administered after a light breakfast, whereas the single-unit dosage forms had extremely variable gastric emptying times (range, 60 to 〉570 min). However, both formulations provided prolonged phenylpropanolamine blood levels. The differences in the blood profiles obtained with the two formulations were attributed to variations in their in vitro release rates and not to any differences in their GI transit times.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 182
    ISSN: 1573-904X
    Keywords: pancreatic lipase ; lipase ; lipolysis ; triglycerides ; kinetics ; mechanism ; calcium ; bile salts ; lecithin ; emulsions
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract Lecithin-stabilized triglyceride emulsions are subject to hydrolysis by pancreatic lipase. The time profiles of these reactions are characterized by a lag-phase and a zero-order phase. Lag phases are more pronounced with long-chain triglycerides. Ca2+ is effective in reducing the lag-phase and activating lipase. Kinetic analysis of the reactions suggests that, like previous findings by others, taurodeoxycholate (TDC) micellar solutions combine with the lipase–colipase complex to form another catalytically active enzyme form. This enzyme form exhibits reduced activity in the absence of Ca2+. In the presence of Ca2+ the mixed micelle–lipase complex becomes more active and opens a new pathway for lipolysis. It is suggested that this enzyme form can bind more easily to interfaces with different physicochemical properties. Under these conditions, Ca2+ activates the lipolysis of short-, medium-, and long-chain triglycerides by a similar mechanism. Maximum activities were measured in the presence of approximately 6 mM TDC and 30 mM Ca2+. The experimental conditions approximate the physiological conditions in the gastrointestinal tract since all of the factors studied here have been reported to be necessary for in vivo lipolysis and/or absorption of triglycerides. A mechanistic model for lipolysis in the presence of Ca2+ and the bile salt TDC is proposed which accounts for most of the experimental observations in a quantitative manner.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 183
    ISSN: 1573-904X
    Keywords: insulin ; collagen ; injection ; subcutaneous injection ; bioavailability
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract The present study was undertaken to develop an agent that stabilizes insulin injected subcutaneously. 125I-Porcine insulin with 0.2 U/kg unlabeled porcine insulin was subcutaneously injected with or without collagen in the rat under the depilated skin of the back. At various times, the radioactivity in subcutaneous tissue was assayed for insulin and its metabolites by gel filtration. The degradation and absorption rate constants of insulin at the subcutaneous injection site were estimated according to a one-compartment model. The degradation rate constant of insulin in the presence of collagen at the injection site was less than half of the control rate. The inhibition was confirmed by increases in the immunoreactive insulin plasma levels and the hypoglycemic effect in rats and healthy volunteers. We postulate that collagen prevents insulin from being degraded by inhibiting proteolytic enzymes, mainly collagenase-like peptidase, in subcutaneous tissue.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 184
    Electronic Resource
    Electronic Resource
    Springer
    Pharmaceutical research 6 (1989), S. 817-821 
    ISSN: 1573-904X
    Keywords: bioavailability evaluation ; absorption ; intraindividual variability ; bioavailability ; intraperitoneal ; lithium pharmacokinetics in rats
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract A method for determination of absorption rate and bioavailability was developed to reduce the influence of intraindividual variability and applied to the absolute intraperitoneal availability of lithium in the rat. In this method the test and the reference doses are given with a few hours' interval, and the resulting concentration–time data are analyzed by nonlinear regression. The bioavailability estimation by this approach was compared to that of the traditional method, with test and reference doses given on separate days. The mean estimates of availability were 1.035 ± 0.109 (N = 7) and 0.984 ± 0.052 (N = 11) for the traditional and the alternative method, respectively. Thus, the precision was better in the latter. Major influences of dose- or time-dependent kinetics of lithium on the availability estimates were excluded by the design used. The estimation of bioavailability was robust with respect to the choice of absorption and disposition model and the duration of sampling. The plasma clearance of lithium was 169 ± 15 ml/hr/kg, with a terminal half-life of 5.0 ± 0.5 hr (N = 5).
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 185
    ISSN: 1573-1561
    Keywords: Sweet potato weevil ; Cylas formicarius elegantulus ; Coleoptera ; Curculionidae ; Ipomoea batatas ; feeding ; oviposition ; host-plant preference ; host-plant resistance ; root surface chemistry
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract Cores from sweet potato [Ipomoea batatas (L.) Lam.] storage roots (Centennial, Jewel, Resisto, and Regal cultivars) were presented to sweet potato weevils [Cylas formicarius elegantulus (Summers) (Coleoptera; Curculionidae)] in multiple-choice, limited-choice, and no-choice bioassays. Centennial, a susceptible cultivar in field-plot experiments, was preferred for feeding and oviposition by female weevils in choice bioassays, and for ovi-position in no-choice bioassays, compared to three other cultivars. Analysis of root surface chemistry showed a tentatively identified triterpenol acetate in Centennial, which was not found in the more resistant cultivars; another root surface component was found in higher concentrations in the more resistant cultivars.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 186
    ISSN: 1573-1561
    Keywords: Enantiomeric composition ; chiral separation ; GC ; pheromone ; plant-insect relations ; Norway spruce ; Picea abies ; α-pinene enantiomers ; cis-verbenol ; trans-verbenol ; Ips. Typographus ; Coleoptera ; Scolytdae
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract The enantiomeric composition of α-pinene in individual Norway spruce trees [Picea abies (L.) Karst.] was determined on a chiral GC column after stereoselective hydroboration-oxidation followed by a reaction with isopropyl isocyanate to form the carbamate derivative. The enantiomeric composition varied considerably between trees of different genetic origin. There was a strong correlation between the chirality of α-pinene in host spruce trees and thecis/trans ratio of verbenols found in the hindguts of the bark beetleIps typographus (L.) infesting the trees.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 187
    Electronic Resource
    Electronic Resource
    Springer
    Journal of chemical ecology 15 (1989), S. 1617-1627 
    ISSN: 1573-1561
    Keywords: Aggregation ; lactic acid ; olfactometer ; mouthpart palpi ; density ; mealworm ; Tenebrio molitor ; Coleoptera ; Tenebrionidae
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract Evaluation of the lactic acid attraction of individual and grouped larvalTenebrio molitor L. in an olfactometer indicated that olfaction is unlikely to be the chemoreceptive mode governing substrate choice or aggregation of these insects. High-magnification videotaped sequences of mealworms on treated and control filter papers indicated that larvae sample the substrate by rapidly probing with mouthpart palpi in a manner similar to the leaf sampling of certain caterpillars. The reception of lactic acid stimuli may therefore involve contact chemoreceptors. The larvae frequently touch each other in a similar manner. Bioassays comparing the cumulative frequencies of distributions of mealworms on control and lactic acid-treated filter papers indicated significant differences, with higher density clusters being found on the treated papers. Comparison of the control distribution with the expected distribution revealed an innate tendency to aggregate. The implications of these results are discussed with regard to the formation of mealworm clusters in the environment.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 188
    Electronic Resource
    Electronic Resource
    Springer
    Journal of chemical ecology 15 (1989), S. 1689-1697 
    ISSN: 1573-1561
    Keywords: Defensive secretion ; aliphatic acids ; beetle ; Coleoptera ; Carabidae ; Pasimachus subsulcatus ; carboxylic acids
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract The defensive secretion of the carabid beetlePasimachus subsulcatus is a concentrated solution (up to 90%) of carboxylic acids, amounting to about 1% of body mass. It contains three major components (methacrylic, tiglic, and angelic acids) and four minor components (isobutyric, 2-methyl-butyric, isovaleric, and senecioic acids). In the single population of this large flightless beetle that was examined, the relative ratio of acidic components was remarkably constant from individual to individual.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 189
    Electronic Resource
    Electronic Resource
    Springer
    Journal of chemical ecology 15 (1989), S. 749-765 
    ISSN: 1573-1561
    Keywords: Bark beetle ; Ips typographus ; Tomicus piniperda ; Coleoptera ; Scolytidae ; pheromone ; host attractants ; dispersal ; flight ; Pityogenes ; Hylurgops ; Cryphalus ; Trypodendron
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract The catches of bark beetles (Coleoptera: Scolytidae) were compared between attractive traps releasing semiochemicals and passive traps (cylindrical sticky screens hung, at 10 heights of 0.7–11.5 m, on poles). A central attractive-trap pole was surrounded by three passive-trap poles spaced 50 or 100 m away at the apices of an equilateral triangle. The catches ofTomicus piniperda and other scolytid species on the attractive-trap pole baited with host monoterpenes, or the catches ofIps typographus attracted to synthetic pheromone, were compared to passive trap catches in a Scots pine forest or in a Norway spruce clear-cut, respectively. Information about flight height distributions of the above scolytid species, andHylurgops palliatus, Cryphalus abietis, Pityogenes chalcographus, P. quadridens, P. bidentatus, andTrypodendron domesticum were obtained on the passive and attractive trap poles. A new method is presented for determining the densities of flying insects based on the passive trap's dimensions and catch, duration of test, and speed of insect. Also, a novel concept, the effective attraction radius (EAR), is presented for comparing attractants of species, which is independent of insect density, locality, or duration of test. The EAR is obtained by the ratio of attractive and passive trap catches and the dimensions of the passive trap, and thus should correlate positively with the strength of the attractant and the distance of attraction. EARs are determined from catch data ofT. piniperda andI. typographus as well as from the data of previous investigations on the same or other bark beetles.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 190
    Electronic Resource
    Electronic Resource
    Springer
    Journal of chemical ecology 15 (1989), S. 1171-1176 
    ISSN: 1573-1561
    Keywords: Host colonization ; sex pheromone ; ambrosia beetle ; Platypus caviceps ; Coleoptera ; Platypodidae ; Nothofagus ; southern beech
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract The role of host- and beetle-produced odors in the colonization of southern beech (Nothofagus spp.) by the pinhole borerPlatypus caviceps Broun was investigated. Host-selecting males attacked the crown zone of a recently felled tree. Beetle emergence and dispersal were influenced by temperature, and sparse colonization continued over the 30 days of the study. Field tests using naturally baited traps indicated that male colonization of southern beech can be accounted for by attraction to host odors alone and that subsequent female response is to a male-released sex pheromone acting alone or in combination with host odors.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 191
    Electronic Resource
    Electronic Resource
    Springer
    Journal of chemical ecology 15 (1989), S. 1545-1558 
    ISSN: 1573-1561
    Keywords: Magnesium sulfate ; oviposition ; bean weevil ; Acanthoscelides obtectus Say ; Coleoptera ; Bruchidae ; supernormal stimulus ; neuromuscular synaptic depression
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract Unlike many secondary plant substances, a wide range of concentrations (4–1000 mM) of magnesium sulfate, applied to dry beans, significantly increased egg-laying by the dry bean weevil in binary choice tests, in favor of treated seeds. No other magnesium-containing compounds studied exerted such an effect, nor was a similar response noted on treated beans in no-choice situations. The total number of eggs laid per female was in the same range in both types of test. Variably enhanced or suppressed oviposition responses were shown on magnesium sulfate-treated secondary hosts and on nonhosts or on indifferent substrates. No specific behavior by egg-laying bean weevil females on Mg-treated seeds could be detected. The results are explained by assuming the functioning of magnesium as a supernormal stimulus for egg-laying. However, a physiological effect on neuromuscular synaptic transmission, as a consequence of probable Mg uptake resulting in a decreased propensity to move, is also hypothesized.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 192
    Electronic Resource
    Electronic Resource
    Springer
    Journal of chemical ecology 15 (1989), S. 1605-1615 
    ISSN: 1573-1561
    Keywords: Aggregation ; lactic acid ; yellow mealworm ; Tenebrio molitor ; frass ; acetic acid ; Coleoptera ; Tenebrionidae ; attraction
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract Late-instar larvalTenebrio molitor L. were found to be attracted to aqueous extracts of conspecific larval frass. The attraction was evident at both the individual and group level. The attraction of larval groups to frass indicated the possibility of an aggregation pheromone that would be chemically distinct in the mealworm environment. Chemical analysis of short carbon chain acids present in both the mealworm frass and the diet indicated that lactic acid was present in the mealworm frass only. Acetic acid was identified in both the diet and the larval frass. Larvae aggregated on filter papers treated with aqueous frass extracts that had been dried and also on those freshly wetted. The larvae also aggregated on dried or freshly wetted papers treated with lactic acid, but failed to aggregate on freshly wetted papers or dried papers treated with acetic acid. The role of excreted lactic acid as a discriminant of already infested and, therefore, safer environmental regions is discussed.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 193
    Electronic Resource
    Electronic Resource
    Springer
    European journal of clinical pharmacology 34 (1988), S. 77-82 
    ISSN: 1432-1041
    Keywords: N-acetylcysteine ; pharmacokinetics ; bioavailability
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary The pharmacokinetics and bioavailability of N-acetylcysteine (NAC) have been determined after its intravenous and oral administration to 6 healthy volunteers. According to a randomized cross-over design each subject received NAC 200 mg i.v. and 400 mg p.o., and blood samples were collected for 30 h. Reduced NAC had a volume of distribution (VSS) of 0.59 l·kg−1 and a plasma clearance of 0.84 l·h−1·kg−1. The terminal half-life after intravenous administration was 1.95 h. The oral bioavailability was 4.0%. Based on total NAC concentration, its volume of distribution (VSS) was 0.47 l·kg−1 and its plasma clearance was 0.11 l·h−1·kg−1. The terminal half-life was 5.58 h after intravenous administration and 6.25 h after oral administration. Oral bioavailability of total NAC was 9.1%.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 194
    ISSN: 1432-1041
    Keywords: BW443C ; enkephalin ; opioid peptide ; healthy volunteers ; pharmacokinetics
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary We have studied 16 healthy men to evaluate preliminary pharmacodynamics and kinetics of BW443C given by i.v. infusions. Four volunteers received escalating doses at weekly intervals, starting at 0.1 µg·kg−1 for 60 min and increasing to a maximum of 2.0 µg·kg−1·min−1 for 180 min. Subsequently 12 different subjects received single i.v. infusions of 10 µg·kg−1·min−1 for 20 min. Subjective effects were reported and objective measurements made of central nervous and cardiovascular effects. Blood was sampled at intervals on all occasions, plasma concentrations were determined by radioimmunoassay and pharmacokinetic profiles were analysed using NONLIN. Dry mouth and some nasal stuffiness were reported and postural hypotension occurred in 5/16 subjects at plasma concentrations 〉0.8 µg·ml−1. Supine blood pressure was well maintained in all subjects and hypotension resolved within 60–90 min of discontinuing the infusion. There was no evidence of sedation, mood change, nausea, vomiting, miosis, change in accomodation or respiratory depression. Rapid infusions produced transient feelings of warmth, heavy eyelids, heavy legs, and increased bowel sounds, which resolved despite increasing plasma concentrations. The disposition of the peptide was adequately described by a 2-compartment model with a mean ± SD plasma clearance of 123±18 ml·min−1 and a half-life of 2.0±0.4 h.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 195
    Electronic Resource
    Electronic Resource
    Springer
    European journal of clinical pharmacology 34 (1988), S. 263-266 
    ISSN: 1432-1041
    Keywords: tyramine ; propranolol ; pressure response ; blood pressure ; beta-adrenoceptor blockers ; healthy volunteers ; indenolol
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary The effect β-adrenoceptor blockade on the pressor response to tyramine has been investigated in 6 healthy volunteers, each submitted to an i.v. tyramine pressor test before and after 7 days of propranolol 40 mg b.d. or indenolol 60 mg o.d. Tyramine was given as i.v. boluses of 1–6 mg, alternating with saline, in a randomized, single blind fashion. Prior to treatment tyramine caused a temporary, dose-dependent increase in systolic and diastolic blood pressure, whilst the heart rate remained unaffected. Both propranolol and indenolol reduced the pressor response to tyramine, as shown by a significant increase in ED15, i.e. the dose of tyramine required to increase systolic blood pressure by 15%.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 196
    Electronic Resource
    Electronic Resource
    Springer
    European journal of clinical pharmacology 34 (1988), S. 315-317 
    ISSN: 1432-1041
    Keywords: albendazole ; echinococcosis ; bioavailability ; food intake ; fatty meal
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary We have studied the systemic availability of oral albendazole in 6 patients with echinococcosis either fasting or with breakfast. Albendazole sulphoxide, the pharmacologically active principle, was assayed by HPLC. Mean plasma concentrations and AUCs were 4.5 times higher when albendazole was given with breakfast than when administered in the fasting state. We conclude that therapy of echinococcosis with albendazole requires the drug to be taken with meals and that administration on an empty stomach might be more appropriate when intraluminal effects are desired, e.g. for intestinal parasites.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 197
    Electronic Resource
    Electronic Resource
    Springer
    European journal of clinical pharmacology 34 (1988), S. 469-473 
    ISSN: 1432-1041
    Keywords: xamoterol ; cardiac failure ; beta1-adrenoceptor partial agonist ; pharmacokinetics ; bioavailability
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary The pharmacokinetics of xamoterol, a β-adrenoceptor partial agonist under clinical evaluation for the treatment of mild to moderate heart failure, have been studied in 12 healthy male subjects. They received 14 mg i.v. and oral doses of 50 and 200 mg as a tablet and 200 mg as a solution in a 4 way cross-over design. After i.v. dosing the elimination half-life was 7.7 h, the total body clearance was 224 ml·min−1 and the volume of distribution at steady-state (Vss) was 48 l. Sixty-two percent of the dose was recovered unchanged in urine. After oral doses, the absolute bioavailability of xamoterol was shown to be 5% irrespective of whether the dose was administered as a tablet or solution. Peak plasma concentrations occurred at about 2 h for the tablet dose and slightly earlier (1.4 h) for the solution. Peak plasma concentration, AUC and urinary recovery of unchanged drug increased in proportion to dose. The apparent elimination half-life after oral doses (16 h) was significantly longer than that observed after an intravenous dose. Despite the low bioavailability, the degree of inter-subject variability of oral bioavailability was small probably indicating that the controlling factor is the hydrophilic nature of the molecule rather than extensive first pass metabolism or poor dissolution of xamoterol from the tablet formulation.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 198
    ISSN: 1432-1041
    Keywords: metoprolol ; controlled-release formulation ; pharmacokinetics ; pharmacodynamics ; exercise heart rate ; healthy volunteers ; efficacy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary The pharmacokinetic and pharmacodynamic properties of a new multiple-unit, controlled-release (CR) formulation of metoprolol1 (metoprolol succinate, 95 mg once daily), which has almost constant (zero-order) release properties over most of a 24-h dose interval, have been compared with those of conventional metoprolol tablets (metoprolol tartrate, 100 mg once daily and 50 mg twice daily), in 12 healthy male volunteers. The steady-state plasma concentrations of metoprolol after five days of treatment varied less throughout the day with the CR than with the conventional formulation. This was associated with a considerably lower peak plasma concentration and the achievement of a significantly higher plasma concentration at the end of the dose interval. Similarly, the effect on exercise-induced tachycardia was maintained at a relatively constant level throughout the day after treatment with the CR formulation. A significantly greater effect 24 h after administration was achieved with the CR formulation, when compared with once-daily dosing with metoprolol tablets, 100 mg. Twice-daily dosing with metoprolol tablets, 50 mg, produced a similar β1-blocking effect at the end of the dose interval to that observed with metoprolol CR. Although the steady-state plasma concentrations indicated significantly lower systemic availability for the CR formulation, compared with both regimens of metoprolol tablets, the total effect over the dose interval, expressed as the area under the efficacy curve (AUEC), was similar for the three treatments. The relationship between steady-state plasma concentrations and the pharmacodynamic efficacy at corresponding times, indicated that plasma concentrations were more effectively utilized after the administration of the CR formulation than after the conventional tablet regimens. The results of this study clearly indicate the potential benefits offered by the new metoprolol CR formulation, under all circumstances where a constant degree of β1-selective blockade, without plasma peaks and troughs, is preferred.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 199
    Electronic Resource
    Electronic Resource
    Springer
    European journal of clinical pharmacology 34 (1988), S. 211-212 
    ISSN: 1432-1041
    Keywords: diclofenac ; sulglicotide ; bioavailability ; drug interaction
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary The bioavailability of diclofenac (D) was assessed in 12 healthy volunteers treated orally with single doses of 100 mg (retard formulation) and subsequently retreated with the same dose of (D) plus sulglicotide (S) 200 mg. (D) blood levels were measured by GLC in samples collected after 1, 2, 4, 6, 8, 12, 24 h. No relevant difference was seen in (D) bioavailability after (S) administration; after 8 h plasma levels of (D) were slightly higher after (S) (p〈0.05), but this difference can be considered incidental only. Thus, sulglicotide does not interfere with the bioavailability of diclofenac, and can be administered concurrently with the latter to prevent possible gastric injury by the antiinflammatory drug.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 200
    Electronic Resource
    Electronic Resource
    Springer
    European journal of clinical pharmacology 34 (1988), S. 283-289 
    ISSN: 1432-1041
    Keywords: piroxicam ; tenoxicam ; cholestyramine ; accelerated drug elimination ; pharmacokinetics ; healthy volunteers
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary We have studied the influence of multiple oral doses of cholestyramine on the single dose pharmacokinetics of tenoxicam and piroxicam in eight healthy young volunteers. Each subject received on two occasions single intravenous injections of 20 mg tenoxicam and on another two occasions single oral doses of 20 mg piroxicam. Both medications were followed by multiple oral doses of either cholestyramine or plain water (placebo). Compared with placebo cholestyramine accelerated the elimination of both drugs. The average values of half-lives were reduced (tenoxicam: 31.9 h vs 67.4 h; piroxicam: 28.1 h vs 46.8 h) due to increases in clearance. Cholestyramine-mediated enhancement of drug elimination was most pronounced in the subjects with a comparatively low baseline drug clearance. Thus, intersubject variability in clearance was smaller when the drug administrations were followed by the anion-exchange resin. The twofold acceleration of tenoxicam elimination in the present study in man contrasts with a much larger effect (five-fold) seen in experiments with dogs. This points to a much easier access of unchanged tenoxicam to the intestinal lumen in the dogs than in man. Comparing the pharmacokinetics of tenoxicam and piroxicam in the same volunteers revealed a high degree of correlation in clearance and half-lives and similar intersubject variabilities in mean kinetic variables.
    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...