Hydroxyl negative chemical ionization mass spectrometry linked with collisionally activated decomposition. A modern analytical tool in Inborn Errors of Metabolism

Two kinds of inborn errors of metabolism, dicarboxylic aciduria and hyperoxaluria, have been studied by means of hydroxyl negative ion chemical ionization [NICI(OH-)], linked with collisionally activated decomposition experiments on the [M-H]- species of the pathognomonic organic acids. This method has led to non-controversial qualitative determinations of C4-C10 dicarboxylic acids and oxalic, glyceric and glyoxylic acids. NICI(OH-) linked with collisionally activated decomposition mass analysed ion kinetic energy spectrometry (CAD MIKES) is proposed herein for diagnostic purposes, as a valid mass spectrometric alternative to standard gas chromatographic/mass spectrometric analysis. The procedure is characterized by simplified sample treatment and by fast execution.