Two-phase electrodriven membrane extraction combined with liquid chromatography for the determination of tricyclic antidepressants in aqueous matrices

A two-phase low-voltage electrodriven membrane extraction (EME) method combined with high performance liquid chromatography (HPLC) was developed for the determination of tricyclic antidepressants (TCAs) in aqueous matrices. Three TCAs, namely imipramine (IMI), amitriptyline (AMI) and chlorpromazine (CHLO) were used as target analytes. The drugs were extracted from aqueous sample solutions through a porous polypropylene membrane filter impregnated with 2-nitrophenyl octyl ether (NPOE) that served as a supported liquid membrane (SLM), and into an acceptor phase with a potential difference of 10 V applied over the SLM. EME parameters such as the type of organic solvent, the pH of sample solution, the extraction voltage, extraction time and stirring rate were evaluated and optimized. Optimal extractions were accomplished using NPOE as the organic solvent, a sample solution of pH 6, an extraction time of 10 min, and 10 V as the driving force with the whole assembly agitated at 1200 rpm. Under the optimized extraction conditions, the method demonstrated good linearity with coefficients of determination, r2 ≥ 0.9987 in the concentration range of 0.5–1000 µg L−1 for water, and 1.0–1000 µg L−1 for urine and good limits of detection in the range of 0.05–0.08 µg L−1 and 0.1–0.3 µg L−1 in water and urine samples, respectively. The method showed high enrichment factors in the range of 91–128 and high relative recoveries in the range of 98.4–103.1% and 86.7–107.4%, for water and urine samples, respectively with RSDs of <9.0% (n = 3). This method was successfully applied to the determination of the drugs in water and human urine samples. The proposed method offered good features such as simplicity, easy handling, fast extraction time, low voltage and minimum organic solvent consumption which meet the green chemistry concept.