Chiral capillary electrophoresis electrospray mass spectrometry coupling using vancomycin as chiral selector

Capillary electrophoresis-electrospray mass spectrometry coupling (CE-ESI-MS) using vancomycin (VC) as a chiral selector is described in this study. The self electrophoretic mobility of VC, as a positively charged chiral selector at low pH, allows us to avoid the contamination of the ion source of the ESI-MS with the chiral selector in a simple way. The usefulness of this technique is illustrated for the analysis of chiral anionic compounds of pharmaceutical importance. Additionally, examples of a stereospecific determination of ibuprofen and its phase I metabolites as well as etodolac and its metabolites in urine samples are described. The advantages of MS for peak identification, peak purity testing and for selective monitoring of overlapping peaks are demonstrated. (C) 1998 Elsevier Science B.V.