Polyaniline immobilized on polycaprolactam nanofibers as a sorbent in electrochemically controlled solid-phase microextraction coupled with HPLC for the determination of angiotensin II receptor antagonists in human blood plasma.

Abstract

In this research, electrospun polycaprolactam nanofibers were collected on a fine stainless steel mesh sheet without a binder, and a layer of conductive polyaniline was chemically deposited on the nanofibers. The polyaniline immobilized on the polycaprolactam nanofibers provided high electrical conductivity, acceptable mechanical stability, and a large surface area. This assembly was then used as a working electrode in electrochemically controlled solid-phase microextraction (EC-SPME), a fast and environmentally friendly method. The polymer layers were characterized by SEM and FTIR techniques. Significant factors affecting the EC-SPME efficiency were investigated, including the desorption conditions, the sorbent used, the pH of the sample solution, the extraction voltage, the extraction time, and the ionic strength. Under the optimum conditions, the limits of detection and quantification for the target analytes were 0.9-1.8μgL-1 and 3.0-6.1μgL-1, respectively. The linear dynamic range was 5-2000μgL-1, with R2 > 0.993. The method was coupled with HPLC analysis and applied to the determination of angiotensin ΙΙ receptor antagonists (ARA-ΙΙs) in human plasma, and relative recoveries of 91.1-104.3% with RSDs of ≤8.3% were obtained.