4-t-Butylbenzylation of carboxylic acid for GC–MS analysis

Abstract We report a 4- t -butylbenzyl derivatization for the analysis of carboxylic acids by GC–MS (EI). Carboxylic acids were analyzed as a 4- t -butylbenzyl ester after the derivatization with 4- t -butylbenzyl bromide. On the mass spectra of 4- t -butylbenzyl ester, [M-15] + ions were observed with high intensity. These ions were tertiary benzyl cations generated by the elimination of a methyl radical from molecular ions. After optimization of the 4- t -butylbenzyl derivatization conditions using microwave reactor, we established a method for the determination of the carboxylic acids in water samples. The method showed good sensitivity and good reproducibility, and was successfully applied to the analysis of rain water samples.