Synthesis and characterization of a poly(p-phenylenediamine)-based electrospun nanofiber for the micro-solid-phase extraction of organophosphorus pesticides from drinking water and lemon and orange juice samples

A new micro-solid-phase extraction sorbent was synthesized by electrospinning poly(p-phenylenediamine)/poly(vinyl alcohol) in the presence of cetyltrimethylammonium bromide. The modified nanofiber was prepared by removing the majority of the poly(vinyl alcohol) from the nanofiber blend by exposing it to the hot water. Scanning electron microscopy and surface analysis were performed to study the homogeneity and porosity of the electrospun nanofiber. In addition, Fourier transform infrared spectroscopy was applied for more characterization. The capability of the new nanofiber was explored by applying it in the extraction and preconcentration of organophosphorus pesticides from aqueous medium. After solvent desorption, the extracted analytes were analyzed by high-performance liquid chromatography with diode array detection. Under the optimum conditions, the relative standard deviation values at the concentration level of 50ng/mL were in the range of 4.8-8.3%. The calibration curve showed linearity in the range of 0.5-500ng/mL, and the limits of detection (S/N=3) for the studied compounds were 0.15ng/mL. By analyzing Tehran drinking water, lemon juice, sour lemon juice, orange juice and sour orange juice, the applicability of the presented method was investigated and the relative recoveries were in the range of 76-102%.