MultiSimplex optimization of the dispersive solid-phase microextraction and determination of fenitrothion by magnetic molecularly imprinted polymer and high-performance liquid chromatography

A magnetic molecularly imprinted polymer (MMIP) was fabricated and used as the sorbent for the MMIP-dispersive solid-phase microextraction of fenitrothion prior its determination by high-performance liquid chromatography equipped with an ultraviolet detector. The MMIP was prepared using functionalized Fe3O4 nanoparticles as the magnetic supporter. Methacrylic acid, ethylene glycol dimethacrylate and fenitrothion were used as the functional monomer, the cross-linker and the template, respectively. The properties of the resultant MMIP were evaluated using X-ray diffraction spectroscopy, Fourier transform infrared spectroscopy and scanning electron microscopy. The sorbent exhibited high selectivity and affinity toward fenitrothion compared to other organophosphate pesticides with the maximum adsorption capacity of 31.5 mg g(-1). The effective variables on the extraction were optimized by univariable and MultiSimplex methods. The calibration curve exhibited linearity over the concentration range of 0.3-50.0 mu g L-1 with the limit of detection of 0.1 mu g L-1. The relative standard deviations at 10.0 mu g L-1 level of FNT (n = 5) for intra- and inter-day assays were 1.6 and 3.1%, respectively. The proposed method was successfully used for the determination of trace amounts of FNT in food and water samples.