γ-MPS-Modified Silica Conical Microcolumn Separation/Preconcentration of Trace Antipsychotic Drugs in Rat Plasma and Environmental Water Samples Prior to Their Determination by LC

Abstract

A conical microcolumn packed with γ-methacryloxypropyltrimethoxysilane (γ-MPS)-modified silica particles was developed for the separation/preconcentration of trace carbamazepine, amitriptyline, quetiapine, clozapine, clomipramine, and thioridazine in rat plasma and environmental water samples followed by liquid chromatography method coupled with ultra-violet detector. The chromatographic analysis was performed on a C₁₈ column under optimal conditions (mobile phase: ammonium acetate (0.03 mol L⁻¹)–methanol–acetonitrile (37.0:44.1:18.9, v/v/v); flow rate: 1.0 mL min⁻¹; detection wavelength: 238 nm; column temperature: 25 °C). The prepared γ-MPS-modified silica particles were characterized by Fourier transform infrared spectroscopy and a Varian Infinity-plus400 NMR spectrometer. Various influencing factors such as pH, elution solvent and volume, flow rate and sample volume were investigated systematically. Under the optimal conditions, the method detection limits and the limits of quantitation were 0.7 and 2.1 ng mL⁻¹ for carbamazepine, 0.4 and 1.3 ng mL⁻¹ for amitriptyline, 0.6 and 1.8 ng mL⁻¹ for quetiapine, 0.7 and 2.1 ng mL⁻¹ for clozapine, 1.5 and 4.7 ng mL⁻¹ for clomipramine, 0.8 and 2.6 ng mL⁻¹ for thioridazine, respectively. The relative standard deviations for six replicates of analytes at 0.050 µg mL⁻¹ were less than 4.1 %. The proposed method was applied to the determination of trace amounts of the analytes in the spiked rat plasma and environmental water samples with satisfactory recoveries. It showed wide potential application in the field of the analysis of pharmaceuticals in real environmental water samples and the therapeutic drug monitoring.