Comparison of silylation and esterification/acylation procedures in GC‐MS analysis of amino acids

Abstract Three derivatization agents used in GC analysis of amino acids were compared: N,O ‐bis(trimethylsilyl)trifluoroacetamide, (BSTFA), N ‐methyl‐ N ‐( tert ‐butyldimethylsilyl)trifluoroacetamide (MTBSTFA), and isobutyl chloroformate (iBuCF). It was shown that the analytical characteristics achieved in the case of silylation with MTBSTFA are comparable to those obtained for esterification/acylation. However, since the former approach requires laborious sample preparation to isolate the compounds in question prior to derivatization, determination of amino acids as N(O,S) ‐alkoxycarbonyl alkyl esters seems to be preferable in many cases. Application of the esterification/acylation procedure to analysis of lyophilized E. coli microbial culture was demonstrated.