Gas-liquid chromatography and mass spectrometry of lanthionine, lysinoalanine, and S-carboxyethylcysteine.

A programmed-temperature gas-liquid chromatographic method of analysis of amino acids as their n-butyl esters of N(O)-trifluoroacetyl derivatives with a dual column system using OV-17 and Dexsil 300 GC as stationary phase is discussed. The method is particularly suitable for analysis of chemically modified amino acids in the hydrolyzates of chemically modified wool and other protein fibers. Combined gas-liquid chromatography-mass spectrometry is used to identify unequivocally the molecular structure of modified amino acids. Lanthionine, lysinoalanine, and S-(2-carboxyethyl)-cysteine in the hydrolyzates of chemically modified wool fibers can be quantitatively analyzed by the gas-liquid chromatographic method of Dexsil 300 GC. N(epsilon)-(2-Carboxyethyl) lysine was detected by the combined gas-liquid chromatography-mass spectrometry in the hydrolyzate of reduced wool treated with acrylonitrile.