On-chip electromembrane extraction of some polar acidic drugs from plasma samples by the development of an active and...

Electromembrane extraction (EME), despite its high performance in the extraction of highly polar basic analytes, has challenges in extracting polar acidic compounds. This is the result of a lack of access to the suitable supported liquid membrane (SLM) for this group of analytes. Therefore, it would be valuable to provide a suitable solution for this problem. Accordingly, in the present study, a new method based on on-chip EME followed by HPLC with UV detection was developed for the extraction and determination of some polar acidic drugs in order to provide high extraction efficiency. Here, a new polymeric sheet was introduced as a support for SLM immobilization, which is not only used to impregnate 1-octanol as SLM but also enhances extraction recovery by exerting effective interactions with target acidic analytes. The polymeric sheet was composed of nanofibers prepared by electrospinning polycaprolactone blended with a composite of graphene oxide and aluminum polycations. Encapsulation of the composite in polycaprolactone nanofibers improved the extraction efficiency of polar acidic compounds by creating additional interactions with the target analytes, including hydrogen bonding, dipole-dipole, π-π stacking, and anion exchange process. The electrospun nanofiber-based sheet was characterized by FE-SEM, EDX, elemental mapping, TEM, and AFM. The extraction parameters were further optimized with an orthogonal-rotatable central composite design (CCD). Applying CCD determined optimal conditions by minimum experiments, and interactions between the parameters were clarified. Under optimized conditions, the proposed method provided extraction recoveries from 36.5 to 64.1%, relative standard deviations less than 5.7% (n = 4), and detection limits of 0.3-0.5 μg L^-1. Furthermore, the proposed method was successfully used for the determination of target analytes in plasma samples, providing good accuracy (87-110%) and precision (3.2-8.8%).