Fast atom bombardment, electron ionization and chemical ionization mass spectrometry of 1,2,3-benzenetricarboxylic acids, inhibitors of the mitochondrial tricarboxylate carrier.

Abstract

It has been discovered that 1,2,3-benzenetricarboxylic acid and some 5-substituted derivatives are specific and competitive inhibitors of the mitochondrial tricarboxylate carrier. In order to characterize these acids a study was carried out using electron ionization (EI), chemical ionization (CI) and fast atom bombardment (FAB) mass spectrometry on the free acids, the potassium salt of 1,2,3-benzenetricarboxylic acid and the corresponding methyl esters. Unimolecular decomposition processes were also studied using B/E linked scan experiments in order to correlate peaks present in the FAB mass spectra of the above compounds. The FAB ionization method, as expected, was the most suitable for analysing the very polar and thermolabile acids and the only method which could be used for the analysis of the potassium salt. EI and CI turned out to be appropriate methods for analysing the less polar and thermostable trimethyl esters.