Simultaneous gas chromatography of volatile and non-volatile carboxylic acids as tert.-Butyldimethylsilyl derivatives

Abstract

Solid phase extraction with subsequent ion pair formation and silylation was investigated for the simultaneous trace enrichment of volatile and non-volatile carboxylic acids from complex aqueous samples. The solid phase extraction of acids was performed using Chromosorb P as the solid sorbent. The ether eluate was treated with triethylamine. The resulting triethylammonium salts of the acids were converted to stable tert.-butyldimethylsilyl (TBDMS) derivatives, which were analyzed by gas chromatography (GC) and GC-mass spectrometry. The characteristic M - 57 ions in the mass spectra of TBDMS derivatives enabled rapid identification of acids. The application of the method to the organic acid profiling of urine and saliva samples is demonstrated.