Combination of electromembrane extraction and electro-assisted liquid-liquid microextraction: A tandem sample preparation method

As a well-known extraction procedure, electromembrane extraction (EME) was combined with electro-assisted liquid-liquid microextraction (EA-LLME) in the present work, which resulted in a promising method. This hyphenated sample preparation method, named EME-EA-LLME, was followed by GC for the determination of two model analytes (clomipramine and imipramine). The effective parameters of both EME and EA-LLME (such as organic solvent, pH of acceptor and sample solutions, voltage and extraction time) were optimized. The proposed EME-EA-LLME procedure demonstrated good linearity with coefficients of determination, R2 ≥ 0.998 over the concentration range of 0.5-750 ng/mL. Limit of detection for both analytes was 0.15 ng/mL. The corresponding repeatability ranged from 6.9 to 12.2% (n = 3). The high enrichment factors were obtained as 770.3 and 561.4 for imipramine and clomipramine, respectively. The advantages of this tandem sample preparation method were low detection limits, simplicity, low cost, and short analysis time (<10 min). Finally, the optimized method was used to extract and determine the analytes in urine and wastewater samples. Overall, the results revealed that the developed EME-EA-LLME procedure had better extraction efficiency in comparison with EME and EA-LLME alone.