Improved Analytical Approach Based on QuECHERS/UHPLC-PDA for Quantification of Fluoxetine, Clomipramine and their Active Metabolites in Human Urine Samples

Abstract

This paper reports, for the first time, the development of a modified Quick, Easy, Cheap Effective, Rugged and Safe (QuEChERS) combined with a dispersive SPE (d-SPE) based clean-up procedure as a new and powerful strategy for the simultaneous and efficient isolation of two different antidepressants, fluoxetine and clomipramine, and their active metabolites in human urine samples. A univariate experimental design with four independent variables such as sample volume, extraction solvent, buffered salts and clean-up step, was performed and used to investigate the effect of process variables on the extraction efficiency. Good linearity was achieved at the studied concentration range (0.1-5.0 g mL -1 ), with correlation coefficients (R 2 ) higher than 0.9961. Low detection limits, ranging between 0.060 and 0.092 g mL -1 were obtained for all analytes, whereas the lowest quantification limit was 0.1 g mL -1 , corresponding to the lowest concentration of the standard curve. The method also showed good results for accuracy, with values ranging from 91% to 105%. Intra-and inter-day precision, expressed as the relative standard deviation (RSD), were also satisfactory (<10%). Consistent recoveries of antidepressants ranging from 86% to 109% were observed when urine samples were fortified at three concentrations, namely 0.1, 2.5 and 5.0 g mL -1 . In order to evaluate the proposed method for clinical use, the QuEChERS/UHPLC-PDA method was applied to analysis of 12 urine samples from depressed patients. a RT: retention time. b max : maximum absorbance values obtained in PDA system detection. c TV: test value of Mandel's Fitting Test.