Natural deep eutectic solvent-based hollow polymer inclusion membrane doped with TiO2 nanoparticles: A new design of polymer inclusion membrane for on-chip electromembrane extraction of fluoroquinolones from food samples prior to liquid chromatography tandem mass analysis.

A new design of polymer inclusion membrane has been proposed with the aim of addressing issues with using common forms of liquid membranes. To do so, a natural deep eutectic solvent (NADES) was employed as an extractant in the structure of the hollow polymer inclusion membrane (HPIM). Besides polyvinyl chloride (PVC) as a base polymer, titanium dioxide nanoparticles (TiO2) as well as polyethylene glycol polymer (PEG) were incorporated into the HPIM structure to achieve a nanocomposite form with a desirable hydrophilicity. The optimal HPIM was composed of 12.5 v/w% of thymol-coumarin NADES, 3.0 w/w% of TiO2 and 40.0 v/w% of PEG based on PVC content. Aiming to compare the applicability, HPIMs with other types of extractants, such as bis(2-ethylhexyl) phthalate (DEHP), and the mixture of DEHP-NADES were also fabricated. To confirm the successful fabrication of the HPIM, containing the aforementioned extractant doped with TiO2 nanoparticles various characterization techniques were employed. The resultant HPIM was employed as a liquid membrane in an on-chip electromembrane extraction (EME) of fluoroquinolones (FQs) from various samples, followed by LC-MS/MS analysis. The parameters influencing extraction performance were analyzed, and the proposed method was validated under ideal conditions. All the samples provided excellent performance concerning limits of detection (0.01-0.08 ng mL-1), and quantification (0.03-0.25 ng mL-1) together with an excellent linearity (R2 ≥ 0.9978). The method indicates the desirable RSDs% in the range of 3.2-7.0 % (intra-day, n = 3 × 3) and 3.8-6.1 % (inter-day, n = 3 × 3) for three spiked levels. The satisfactory relative recoveries fell within the 92.0-115.0 % range.