M. Gergov et al., Automated liquid chromatographic/tandem mass spectrometric method for screening beta-blocking drugs in urine, J MASS SPEC, 35(7), 2000, pp. 912-918
An automated liquid chromatographic/tandem mass spectrometric (LC/MS/MS) me
thod is presented for the screening and confirmation of 16 beta-blocking dr
ugs in clinical and autopsy urine samples. The described method involved C-
18 solid phase extraction, LC separation and MS analysis on a triple-stage
quadrupole mass analyser, Samples were initially pre-screened for the prese
nce of any beta-blocking drugs using LC/MS with selected ion monitoring. An
y compounds tentatively identified as beta-blocking drugs on the basis of t
heir LC retention time and protonated molecular ion were then automatedly s
ubjected to a second analysis in which the relevant MS/MS product ion mass
spectra were acquired. These product ion mass spectra were then automatical
ly searched against a 400-substance mass spectral library containing previo
usly acquired beta-blocking drugs. The results demonstrated that library se
arch of beta-blocking drugs in urine with MS/MS product ion mass spectra wa
s more reliable and produced fewer false negatives than library searching w
ith mass spectra derived from single-stage quadrupole MS. The limits of ide
ntification in the MS/MS product ion scan ranged from 0.02 mg l(-1) for car
vedilol to 1.2 mg l(-1) for pindolol, the majority of the values being belo
w 0.2 mg l(-1). Copyright (C) 2000 John Wiley & Sons, Ltd.