Capillary electrophoresis-electrospray ion-trap mass spectrometry for the separation of chlorophenols

Eighteen positional isomers of chlorophenols were separated by capillary el ectrophoresis (CE) and detected on-line by electrospray ionization ion-trap mass spectrometry (MS). Conditions for the coupling of CE to MS, e.g., the concentration of carrier electrolyte, the sheath liquid composition and th e sheath gas flow-rate were optimized. Diethylmalonic acid (5 mM) at pH 7.2 5 and isopropanol-250 mM dimethylamine (80:20) as sheath liquid were used. The activation parameters for ion-trap mass spectrometric analysis of chlor ophenols were optimized. The mass spectra, obtained for all the analytes, r evealed that the [M-H](-) ion was the base peak for all chlorophenols. More over, conditions for CE-MS-MS detection were established and [M-H-HCl](-) i ons were detected. (C) 2000 Elsevier Science B.V. All rights reserved.