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 a queous medium is extended with the use of a variety of alkyl chlorofor mate reagents. This provides a new and convenient procedure for prepar ing esters with different alkoxy groups. A new mechanism for esterific ation during chloroformate derivatization is proposed based on the for mation of an intermediate mixed carboxylic-carbonic acid anhydride fol lowed by the exchange with an alcohol. Among the different reagents in vestigated, isobutyl chloroformate derivatized amino acids were found to provide more sensitivity for analyses by GC-flame ionization detect ion and GC-MS relative to derivatives prepared by other alkyl chlorofo rmates.