SELECTIVE DETERMINATION OF HALOPERIDOL IN HUMAN SERUM - SURFACE-IONIZATION MASS-SPECTROMETRY AND GAS-CHROMATOGRAPHY WITH SURFACE-IONIZATIONDETECTION

Surface ionization organic mass spectrometry (SIOMS) has been performe d on the clinically important drug haloperidol using quadrupole mass s pectrometry in which the thermal ion source has a rhenium oxide emitte r. The surface ionization (SI) mass spectrum is presented, interpreted in a purely empirical way by means of evidence from previous investig ations, and then compared to results from conventional electron impact (EI) ionization. An approach to detection of this drug in serum by ga s chromatography (GC) with a surface ionization detector (SID) and GC- SIOMS is described. This approach demonstrates that (a) haloperidol is efficiently surface-ionized, giving a unique SI mass spectrum (b) exp erimental results rationalize the combined sensitivity and selectivity of the GC-SID for the examined drug, (c) the detection limit for halo peridol in serum is 1.1 ng/ml (S/N = 3) by GC-SID (the coefficients of variation of the assay are generally low, i.e. below 8.5%) and (d) th e GC-SIOMS coupling can be used for sensitive and selective detection of haloperidol in serum.