Sensitive Liquid Chromatography–Tandem Mass Spectrometry Method for the Determination of Olanzapine in Human Urine

A sensitive and selective liquid chromatographic-tandem mass spectrometric (LC–MS–MS) method was developed to determine olanzapine (OLZ) in human urine. After solid-phase extraction with SPE cartridge, the urine sample was analysed on a C18 column (Symmetry 3.5 μm, 50 × 4.6 mm i.d) interfaced with a triple quadrupole tandem mass spectrometer. Positive electrospray ionization was employed as the ionization source. The mobile phase consisted of ammonium acetate (pH 7.8)-acetonitrile (10:90, v/v). The method was linear over a concentration range of 1–100 ngml−1. The lower limit of quantitation was 1 ngml−1. The intra-day and inter-day relative standard deviation across three validation runs over the entire concentration range was <11.5 %. The accuracy determined at three concentrations (8.0, 50.0 and 85.0 ngml−1 OLZ) was within ±1.21 % in terms of relative errors.