Karel Macek

Gas chromatography of amino acids

This review summarizes all papers that have appeared on the gas chromatography of amino acids (including the iodoamino acids) and their enantiomers in the period 1956-mid-1974. It has been found that the methods used for analysis of amino acids can be divided into three classes: (1) degradative procedures and techniques for converting the amino acid into another chemical compound; (2) procedures based on esterification of the carboxyl group and derivatization of the a-amino and other reactive groups in at least two steps; and (3) procedures based on a simultaneous derivatization of the carboxyl and a-amino groups in one reaction medium. For the treatment of the amino acid or its alkyl ester, three approaches can be distinguished for the two latter cases, i.e., acylation, alkylation (including silylation) and condensation. Of the procedures used for the resolution of optical antipodes, two methods are discussed, namely analysis of diastereoisomers on optically inactive stationary phases and separation of enantiomers on optically active stationary phases.

Determination of fatty acids as phenacyl esters in rat adipose tissue and blood vessel walls by high-performance liquid chromatography

Twenty-two biologically relevant (6:0-22:6) saturated, monounsaturated and polyunsaturated fatty acids were separated by reversed-phase high-performance liquid chromatography after derivatization with phenacyl bromide. An optimal resolution of the critical combinations linolenic-myristic, docosahexaenoic-palmitoleic-arachidonic and palmitic-oleic acids and cis and trans isomers of octadecenoic (n9) and octadecadienoic (n9, 12) acids was achieved by continuous gradient elution with methanol-acetonitrile-water. Elution of mixtures of 6:0-22:1 fatty acids was completed within 80 min at a flow-rate of 1 ml/min. By the use of UV detection at 242 nm the detection limits for short- and long-chain fatty acids were found to be about 0.8 and 12 ng per injection, respectively. Linearity was tested up to 100 ng. The method was applied to the determination of fatty acids in rat adipose tissue and blood vessel walls of animals fed hydrogenated fat diets. The results are comparable to those obtained by gas chromatography and surpass the latter for the resolution of oleic and elaidic acids.

Application of the sorption properties of spheron gels in high-resolution liquid column chromatography of naturally occurring macromolecular species

Abstract Sorption effects, in addition to molecular sieving properties, of Spheron P 1000 gel (grain size less than 25 μm) were exploited for the separation of complex naturally occurring mixtures of high-molecular-weight compounds. The applicability of this approach was demonstrated on the separation of glycosaminoglycans and proteoglycan. In both examples, separations exceeding those obtained with conventional sorbents and ion exchangers were achieved.

Changes in the proportion of collagen type IV with age—possible role in transport processes

Abstract It has been proved that collagen type IV, typical for basement membranes, accumulates both in kidney cortex and in the whole body of laboratory rats and golden hamsters. Similar increase in the proportion of this protein was observed also in bovine and human increased incidence of proteinuria in laboratory rodents (as demonstrated experimentally) and with the increased thickness of the basement membrane (McNelly and Dittmer, 1976). It appears possible that the impaired response of the old laboratory rodents to various stimuli reflects, besides other factors, the distortion of transport processes caused by the accumulation of specific collagen types.

Vergleich der reproduzierbarkeit in der papier- und dünnschichtchromatographie : Einführungsreferat

Abstract Comparison of the reproducibility in paper and thin-layer chromatography In this introductory lecture the reproducibility in paper and thin-layer chromatography is examined. The factors that are responsible for non-repreducibility are discussed and possibilities of increasing the responsibility are indicated.

Papierchromatographie einiger 2- und 6-substituierter purine

Zusammenfassung In der vorliegenden Arbeit wurde das chromatographische Verhalten von einunddreissig 2- und 6-substituierten Purinen in sechs Losungsmittelsystemen und ihr Nachweis mit acht Reagenzien beschrieben.

Papierchromatographie von γ-aryl-α,β-dihalogen-Δα,β-crotonlactonen und ähnlichen substanzen

Zusammenfassung In der vorliegenden Arbeit wurde das chromatographische Verhalten von 28 substituierten Crotonlactonen und 24 substituierten aromatischen Sauren untersucht. Es wurden optimale Bedingungen fur den Nachweis und Systeme zur Trennung und Charakterisierung dieser Substanzen gefunden und die Beziehungen zwischen dem chromatographischen Verhalten und der Struktur dieser Verbindungen untersucht.