ANALYSIS OF AMINO-ACIDS BY GAS CHROMATOGRAPHY-FLAME IONIZATION DETECTION AND GAS-CHROMATOGRAPHY MASS-SPECTROMETRY - SIMULTANEOUS DERIVATIZATION OF FUNCTIONAL-GROUPS BY AN AQUEOUS-PHASE CHLOROFORMATE-MEDIATED REACTION

The one-step ethyl chloroformate derivatization of amino acids in an aqueous medium is extended with the use of a variety of alkyl chloroformate reagents. This provides a new and convenient procedure for preparing esters with different alkoxy groups. A new mechanism for esterification during chloroformate derivatization is proposed based on the formation of an intermediate mixed carboxylic-carbonic acid anhydride followed by the exchange with an alcohol. Among the different reagents investigated, isobutyl chloroformate derivatized amino acids were found to provide more sensitivity for analyses by GC-flame ionization detection and GC-MS relative to derivatives prepared by other alkyl chloroformates.