Development of dispersive liquid-liquid microextraction with solid-phase evaporation as a novel hyphenated method prior to ion mobility spectrometry and its application for trace analysis of fluoxetine

For the hyphenating of dispersive liquid-liquid microextraction (DLLME) with nano mesoporous solid-phase evaporation (SPEV) as a novel method, MCM-41@SiO2 was synthesized and used as a nano mesoporous adsorbent for coating on the solid-phase fiber, preconcentration of fluoxetine antidepressant drug (as a model compound), and total evaporation of the extraction solvents obtained by the DLLME method. To detect the analyte molecules, a corona discharge ionization-ion mobility spectrometer (CD-IMS) was applied. In order to increase the extraction efficiency and the IMS signal of the fluoxetine drug, some variables including extraction solvent and its volume, disperser solvents and its volume, sample solution pH, desorption temperature, and evaporation time of the solvent from the solid-phase fiber were chosen and optimized. Some analytical parameters including limit of detection (LOD), limit of quantification (LOQ), linear dynamic range (LDR) with determination coefficient, and relative standard deviations (RSDs) were calculated under the optimized conditions. LOD (S/N = 3), 3 ng mL(-1); LOQ (S/N = 10), 10 ng mL(-1); LDR, 10-200 ng mL(-1); and intra- and inter-day RSDs (n = 3), 2.5% and 9.6% for 10 ng mL(-1), and 1.8% and 7.7% for 150 ng mL(-1), respectively. To investigate the ability of the hyphenated method to determine fluoxetine in real samples, fluoxetine tablets, and some biological samples such as human urine and blood plasma were selected and the relative recovery values were calculated to be 85-110%. The accuracy of the proposed method was compared with that of the HPLC standard method.