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.
Wang
J
J
Department of Chemistry, Michigan State University, East Lansing 48824.
Huang
Z H
ZH
Gage
D A
DA
Watson
J T
JT
D000596:Amino Acids / Q000032:analysis*; D002849:Chromatography, Gas / Q000379:methods*; D005410:Flame Ionization; D005561:Formates; D008401:Gas Chromatography-Mass Spectrometry / Q000379:methods*; D014867:Water
D000596:Amino Acids; D005561:Formates; D014867:Water; C083354:chlorocarbonic acid