Gas chromatography-mass spectrometry in the study of the adsorption of sulfur-containing amino acids on graphitized thermal carbon black

Summary

Gas chromatographic — mass spectrometric study of the trifluoroacetyl-methyl esters of sulfur- and hydroxyl-containing amino acids such as methionine, cysteine, D-β,β′-dimethylcysteine (D-penicillamine), serine, and threonine was carried out. Sterling hydrogen treated graphitized thermal carbon black (HTGTCB) was used as the adsorbent. The Henry's constants, and the initial differential adsorption heats of these amino acid derivatives were determined on the HTGTCB surface by gas chromatography.

Introduction of two methyl groups into the β-position of a cysteine molecule (β,β′-dimethylcysteine) stimulates the intramolecular nonvalent interactions increasing the internal rotation barriers in the molecule. This is revealed in the sharply reduced retention of the β,β′-dimethylcysteine derivative on the HTGTCB surface (as compared to the cysteine derivative) and it also influences the fragmentation pathways under electron impact.