Low-voltage electrochemically stimulated stir membrane liquid-liquid microextraction as a novel technique for the determination of methadone.

In the present work, for the first time, a new portable setup was designed, developed and presented for the extraction of methadone, as a basic drug model from biological fluid samples using a low-voltage electrically stimulated stir membrane liquid-liquid microextraction technique (LV-ESSM-LLME), followed by high-performance liquid chromatography with ultraviolet detection. This new approach combines the advantages of stir membrane liquid-liquid microextraction and electrokinetic migration in the same unit under soft electrochemical conditions in a portable device, allowing for the isolation and preconcentration of the target analyte in a simple and efficient manner under three-phase mode. To investigate the influence of external stirring and the application of electrical potential as the driving force, a comparative study of all variables involved in the extraction process was carried out using the low-voltage electromembrane extraction (LV-EME) and LV-ESSM-LLME methods. Under soft electrokinetic migration conditions, methadone was transported from an acidic sample solution (pH 4.0), through the NPOE immobilized in the pores of the porous polypropylene sheet membrane, and into 25µL of 10mmolL-1 HCl acceptor solution with a stirring rate of 1000rpm and 700rpm after 15min and 20min for LV-ESSM-LLME and LV-EME, respectively. Under the optimized conditions, preconcentration factors in the range of 17-24 and 21.5-29 for LV-EME and LV-ESSM-LLME, respectively, were considered, and satisfactory repeatability (4.5<[RSD]<7.5) was obtained in different matrices. The obtained relative recoveries of the target analyte were in the range of 87-94% and 93-101% for LV-EME and LV-ESSM-LLME, respectively, which indicated the excellent capability of the developed methods to extract methadone from complex matrices.