Author(s): Verplaetse R, Cuypers E, Tytgat J
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Abstract A sensitive liquid chromatography tandem mass spectrometry method was developed and validated for simultaneous detection of benzodiazepines, benzodiazepine-like hypnotics and some metabolites (7-aminoflunitrazepam, alprazolam, bromazepam, brotizolam, chlordiazepoxide, chlornordiazepam, clobazam, clonazepam, clotiazepam, cloxazolam, diazepam, ethylloflazepate, flunitrazepam, flurazepam, loprazolam, lorazepam, lormetazepam, midazolam, N-desmethylflunitrazepam, nitrazepam, N-methylclonazepam (internal standard), nordiazepam, oxazepam, prazepam, temazepam, tetrazepam, triazolam, zaleplon, zolpidem, zopiclone) in urine and whole blood. Sample preparation was performed on a mixed-mode cation exchange solid phase extraction cartridge. Electrospray ionization was found to be more efficient than atmospheric pressure chemical ionization. The use of a mobile phase of high pH resulted in higher retention and higher electrospray ionization signals than the conventional low pH mobile phases. Considering the benefits of a high pH mobile phase on both chromatography and mass spectrometry, its use should be encouraged. In the final method, gradient elution with 10 mM ammonium bicarbonate (pH 9) and methanol was performed on a small particle column (Acquity C18, 1.7 μm, 2.1 mm × 50 mm). The optimized method was fully validated. Copyright © 2012 Elsevier B.V. All rights reserved.
This article was published in J Chromatogr A
and referenced in Pharmaceutica Analytica Acta