Combination of electromembrane extraction with dispersive liquid-liquid microextraction followed by gas chromatographic analysis as a fast and sensitive technique for determination of tricyclic antidepressants

For the first time, combination of electromembrane extraction (EME) and dispersive liquid-liquid microextraction (DLLME) followed by gas chromatography-flame ionization detection (GC/FID) was developed for determination of tricyclic antidepressants (TCAs) in untreated human plasma and urine samples. Response surface methodology (RSM) was used for optimization of experimental parameters, so that extraction time of 14 min, voltage of 240 V, donor phase of 64 mM HCl and acceptor phase of 100 mM HCl were obtained as optimal extraction conditions. Matrix effect and carry-over were investigated in this work. The results indicated matrix effect for urine and plasma samples in comparison with neat solutions, so match matrix method was used for drawing working calibration curves. However, no carry-over was appeared at the retention time of investigated TCAs (S/N < 3). With application of optimized values, good linearity in the range of 2-500 mu g L-1 was obtained for TCAs with the correlation of determination values (r(2)) above 0.9968. The limits of detection (S/N = 3) for TCAs were found 0.25, 3.0, and 15 mu g L-1 in water, urine, and plasma, respectively. The preconcentration factors of TCAs in water, urine, and plasma were from 383 to 1065. The intra- and inter-assay precisions (%) were in the ranges 6.4-11.8% and 6.2-10.8%, respectively, and the intra- and inter-assay accuracies were >86.5%. The results showed that EME-DLLME-GC/FID is a promising combination for analysis of TCAs present at low concentrations in biological matrices. (c) 2012 Elsevier B.V. All rights reserved.