Development of ultrasound assisted dispersive micro solid phase extraction based on CuO nanoplate-polyaniline composite as a new sorbent for insecticides analysis in wheat samples

Abstract

A simple, fast and highly sensitive preconcentration method based on dispersive micro-solid phase extraction (D-µSPE) was developed using CuO nano plate-polyaniline composite (CNPC). The method was applied for the determination of diazinon and imidacloprid insecticides followed by high performance liquid chromatography (HPLC) analysis. The sorbent was characterized by scanning electron microscopy (SEM), Fourier transform- infrared (FT-IR) and x-ray detection (XRD). Experimental design was applied for optimization of the effective parameters on the extraction efficiency such as sample pH, extraction and desorption times, ionic strength and eluent volume. Optimized conditions were obtained as sample pH of 8.0, 100 µl of eluent, adsorption and desorption times of 12.5 and 23 min, respectively and 30% (w/v) of NaCl when 11 mg of the sorbent was applied. The adsorption isotherms were investigated for diazinon and imidacloprid and the results showed better fitness with the Langmuir model. The adsorption capacity of CNPC for diazinon and imidacloprid were calculated 12.18 and 2.58 mg g−1, respectively. Under the optimized conditions, limits of detection of 3 and 0.056 µg Kg−1 and relative standard deviations of 1.7% and 3.7% were obtained for diazinon and imidacloprid, respectively. Relative recoveries up to 99% were achieved indicating good adsorption efficiency of the sorbent. Finally, the developed method was successfully applied for the determination of trace amount of the target analytes in grain samples.