Showing papers in "Journal of Chromatography A in 1982"

TL;DR: The developed extraction system makes use of the complex formation, in alkaline medium, between diphenylborate and the diol group in the catecholamines in combination with ion-pair formation to isolate adrenaline, noradrenaline and dopamine from plasma and urine.

TL;DR: In this article, the linear velocity of electro-osmosis in a capillary tube 30 ×90 cm x 30 −200 μm I.D. was measured, and the physical and geometrical parameters of EOSMosis and its use were discussed.

TL;DR: A linear retention index system for temperature-programmed capillary gas chromatography of polycyclic aromatic compounds using naphthalene, phenanthrene, chrysene, and picene as internal standards has been used in this laboratory for routine analysis since 1979 as discussed by the authors.

TL;DR: In this article, an improved, simple and rapid method for the determination of formaldehyde and other aldehydes in automobile exhaust was developed, which eliminates the timeconsuming and lengthy recovery steps required in other procedures and allows direct injection of an aliquot of the sample into a high-performance liquid chromatograph for analysis.

TL;DR: In this article, it was shown that retention volumes can be calculated in terms of the total material content in the chromatographic column as transported by the eluent, termed the column capacity.

TL;DR: In this article, the effect of the structure of the stationary phase on retention and selectivity in reversed-phase liquid chromatography was studied, using chemically bonded stationary phases on silica gel.

TL;DR: In this article, the effect of solvent modifier(s) in the sample solution to improve solute resolution, peak detection and column selectivity and to reduce analysis time of the narrow-bore microparticle-packed column high-performance liquid chromatography is proposed and demonstrated.

TL;DR: In this paper, a modified technique is described which maximizes extraction of the esters into iso-octane solution, and thereby improves quantitative accurachy and precision for esters down to and including methyl caproate.

TL;DR: In this article, the retention gap is proposed as a method of eliminating peak distortion caused by band broadening in space, where the retention in the colum inlet (the approximate length of the flooded zone) is reduced to accelerate the migration of sample components and to reconcentrate them at the beginning of the regular film of the stationary phase.

TL;DR: Glycosidic derivatives of monoterpene flavourants of grapes and wines can be preparatively isolated by selective retention on a C 18 -bonded reversed-phase adsorbent.

TL;DR: In this article, the modified sequential simplex algorithm was used as the basis for the unattended optimisation of reversed-phase liquid chromatographic separations and a chromatogram response function was computed to evaluate individual chromatograms with respect to resolution and analysis time.

TL;DR: In this paper, the capacity ratio (k) and partition coefficients in the octanol-water system (PO,,_) were investigated using LiChrosorb RP-18, using methanol-water mixtures as eluents at 25'C.

TL;DR: In this article, the retention behavior of 100 peptides was studied during high-performance liquid chromatography on a C18 column using aqueous trifluoroacetic acid as the mobile phase and acetonitrile as a mobile phase modifier in a linear gradient elution system.

TL;DR: In this article, a retention index scale based on the relative retentions of the alkylarylketones (PhCOr) has been evaluated for reversed-phase high-performance liquid chromatography.

TL;DR: The use of a multi-layer coiled column promotes retention of the stationary phase with a high flow-rate of the mobile phase and permits almost universal application of conventional two-phase solvent systems as mentioned in this paper.

TL;DR: In this article, the applicability of various peroxids and azo compounds for free radical cross-linking and the effects that these free radical generators have on commercially available stationary phases are described.

TL;DR: In this paper, a centrifugal counter-current chromatograph with a rotary seal joint has been developed for separations of a set of dinitrophenyl amino acids and application examples of the method to the separation of some biological materials are presented.

TL;DR: In this article, the authors evaluated the utility of pre-column amino acid derivatization, liquid chromatographic separation and subsequent quantitation, and concluded that the results are significantly better at the lower picomole level, an area where few if any analyzers can perform routinely.

TL;DR: In this paper, a reverse-phase thin-layer chromatography with methanol-water as eluent was used to study relationships between retention and hydrophobicity of non-polar aromatic compounds.

TL;DR: Most monosaccharides, including 3-uloses and branched-chain species formed by the autocatalytic condenstation of formaldehyde, have been separated by capillary gas chromatography (GC) and isobutane chemical ionization GC-mas spectrometry (MS) on OV-225 of the trifluoroacetyl n-butoximes, and identified using commercial sugars, oxidation products of alditols and aldolization products of formsaldehyde and/or glycolaldehyde and trioses, and by selected

TL;DR: In this paper, an improved purification procedure is described for high-performance liquid chromatography (HLPC) analysis of ecdysteroids, which can be used for both qu antitative analyses of ecdysone and 20-hydroxlyecdysone, and for various metabolic studies.

TL;DR: In this article, a systematic approach is described for the optimization of solvent selectivity in liquid-solid chromatography (LSC), with emphasis on changes in selectivity as a result of variation of mobile phase composition.

TL;DR: In this paper, an approach to total amino acid analysis utilizing off-line pre-column fluorescence derivatization is described, where the full array of natural primary amino acids was treated with o -phthaldialdehyde (OPA) in the presence of mercaptans, and the highly fluorescent reaction products were separated on an ODS 5-μm reversed-phase column with gradient elution development.

TL;DR: In this article, the advantages of using the selective properties of cyclodextrins for chromatographic separations and the possibilities of studying inclusion processes of different cyclodeextrins with various types of substances, in the liquid as well as in the gaseous phase, are demonstrated and discussed.

TL;DR: An isocratic high-performance liquid chromatographic system for the quantitation of AMP, ADP and ATP is presented and a selective retention of the adenine nucleotides as a group relative to the mono, di and triphosphates of guanosine, uridine and cytidine was observed.

TL;DR: In this article, a rapid and reliable procedure utilizing the best features of the literature methods was developed and shown to give excellent quantitative results in the difficult case of a triacylglycerol primary standard mixture simulating coconut oil.

TL;DR: In this article, the ability of a reversed phase high-performance liquid chromatographic system to separate flavonoids [LiChrosorb RP-18 and a combination of an isocratic and a gradient (5% aqueous formic acid and methanol) technique] was studied.