Three-phase hollow fiber microextraction based on two immiscible organic solvents for determination of tricyclic antidepressant drugs: Comparison with conventional three-phase hollow fiber microextraction

The aim of this research was to compare the extraction efficiencies of two modes of three-phase hollow fiber microextraction (HF-LLLME) based on aqueous and organic acceptor phases for analysis of tricyclic antidepressant (TCA) drugs. High-performance liquid chromatography with photodiode array detection (HPLC-DAD) was applied for determination of the drugs. In order to examine the ability of the new concept of HF-LLLME based on organic acceptor solvent in comparison with aqueous acceptor phase to extract the analytes, four TCAs were selected. The effect of different extraction conditions (i.e., type of acceptor phase, hollow fiber length, ionic strength, stirring rate, and extraction time) on the extraction efficiency of the TCAs was investigated and optimized using central composite design (CCD) as a powerful tool. Both methods were characterized by good linearity and high repeatability, but HF-LLLME with organic acceptor provided higher extraction efficiency and thus lower limits of detection (LODs). Calibration curves were linear (r(2) > 0.996) in the range of 0.2-20014 mu g L-1. LODs for all the TCAs ranged from 0.08 to 0.2 mu g L-1 using HPLC-DAD. Also an improvement in sensitivity of several orders of magnitude was achieved using single-ion monitoring GC-MS analyses (0.04 mu g L-1) due to compatibility of this technique with GC instrument. The applicability of the proposed HF-LLLME/GC-MS and HPLC-DAD methods was demonstrated by analyzing the drugs in spiked urine and plasma samples. The obtained recoveries of the drugs in the range of 87.9-109.2% indicated the excellent capability of the developed method for extraction of TCAs from complex matrices. (C) 2011 Elsevier B.V. All rights reserved.