GAS CHROMATOGRAPHY OF VOLATILE AMINO ACID DERIVATIVES. II. LEUCINE, CYSTEINE, PROLINE, HYDROXYPROLINE, METHIONINE, PHENYLALANINE, ASPARTIC ACID AND GLUTAMIC ACID

Gas-liquid chromatographic analysis of long chain isomeric glyceryl monoethers

A quantitative method is described for the gas chromatographic analysis of glyceryl ethers using their trifluoroacetate (TFA) and trimethylsilyl (TMS) ether derivatives. Both derivatives are prepared at room temperature by reactions that proceed virtually to completion in less than 15 min, eliminating time-consuming derivative preparations and laborious clean-up steps of unreacted materials required by other methods. Gas-liquid chromatography (GLC) resolves the 1- and 2-isomers of the glyceryl ether TFA derivatives, which have not been separated previously. Purified synthetic 1- and 2-glyceryl ethers, including saturated and mono- and diunsaturated, were used to evaluate several polar and nonpolar liquid phases for the analysis of the TFA and TMS derivatives. Analyses can be made on some liquid phases normally used for methyl esters, while others are unsatisfactory. A mixture of isomeric C(18) saturated and monoand di-unsaturated TFA derivatives was partially resolved; however, a complete analysis of this mixture can be made by preliminary separation of the unsaturates on silver-ion-impregnated thin-layer plates or by GLC analysis alone with three different phases.

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.