THE EFFECT OF ORGANIC-SOLVENTS ON THE DETERMINATION OF CYCLIC BORONATES OF SOME BETA-BLOCKERS BY GAS-CHROMATOGRAPHY MASS-SPECTROMETRY

Formation cyclic boronates for beta-blockers, by use of triethylamine (TEA) and pyridine as catalysts, gives more effective product: yield. Eleven beta-blockers, formed by cyclic boronation with n-butylboronic acid and TEA, produced higher yields than by on-column thermal reactio n and seven beta-blockers were shown to give the highest yields in the phenyl cyclic boronation with pyridine or TEA by on-column thermal an d general reaction, The phenyl cyclic boronate of nadolol produced one peak in the chromatogram and the n-butyl cyclic boronate showed two p eaks. On-column derivatization with n-butylboronic acid and pyridine w as effective in saving analysis time and for convenience, even though some n-butyl cyclic boronates by cyclic boronation with TEA gave a bet ter yield, In IE-butyl cyclic boronation with pyridine by on-column th ermal reaction the detection limits were 0.1 to 4 ng/mu L in urine wit h a signal-to-noise ratio of 10:1. (C) 1998 John Wiley & Sons, Ltd.