Extraction and determination of some psychotropic drugs in urine samples using dispersive liquid–liquid microextraction followed by high-performance liquid chromatography

Abstract

A simple, rapid and sensitive method termed as dispersive liquid–liquid microextraction (DLLME) combined with high-performance liquid chromatography-ultraviolet detector (HPLC-UV) has been proposed for the determination of three psychotropic drugs (amitryptiline, clomipramine and thioridazine) in urine samples. The determination was performed on a C 8 column under the optimal chromatographic conditions (mobile phase: ammonium acetate (0.03 mol L −1, pH 5.5)–acetonitrile (60:40, v/v); flow rate: 1.0 mL min −1; detection wavelength: 238 nm). Several factors influencing the extraction efficiency of the target drugs, such as pH, extraction and disperser solvent type and their volume, extraction time and ion strength were studied and optimized. Under the optimal DLLME conditions, the absolute recoveries of amitryptiline, clomipramine and thioridazine from the urine samples were 96, 97 and 101%, respectively. The detection limits (LODs) and quantification (LOQs) of the proposed approach were 3 and 10 ng mL −1 for amitryptiline, 7 and 21 ng mL −1 for clomipramine, and 8 and 25 ng mL −1 for thioridazine, respectively. The relative standard deviations (RSDs) for nine replicate determinations at 0.100 μg mL −1 level of target drugs were less than 4.8%. Good linear behaviors over the investigated concentration ranges were obtained with the values of R 2 > 0.998 for the target drugs. The proposed method was successfully applied to the real urine samples from two female patients under amitryptiline and clomipramine treatment, respectively.