Analysis of diagnostic metabolites by capillary electrophoresis-mass spectrometry

We describe here a procedure by capillary electrophoresis-mass spectrometry (CE-MS) for the direct analysis of urine samples on diagnostic metabolites , which are present in patient urine with metabolic disorders. The method w as demonstrated using urine samples spiked with diagnostic metabolites, inc luding glutathione for gamma-glutamyl transpeptidase deficiency, pyroglutam ate for generalized glutathione deficiency, adenylosuccinate for adenylosuc cinase deficiency, ornithine for gyrate atrophy, histidine for histidinemia , and homogentisic acid for alcaptonuria, at concentrations similar to thos e found in patients' urine. A coaxial sheath liquid flow was used for coupl ing CE and MS in electrospray ionization mode. Identification of the metabo lites is based on their molecular weights and fragmentation patterns. The C E-MS method is highly specific and sensitive comparing to the previously re ported method using migration time and UV absorption for identification. It should find broad application in clinical and pharmaceutical research and development. (C) 1999 Elsevier Science B.V. All rights reserved.