Ultrasonication assisted extraction of chlorpyrifos from honey and brinjal using magnetic molecularly imprinted polymers followed by GLC-ECD analysis

Abstract

Chlorpyrifos selective magnetic molecularly imprinted polymers (MMIPs) were synthesized by precipitation polymerization using acrylic acid as monomer and ethylene glycol dimethacrylate as cross linker. Properties of prepared polymers were determined using Fourier Transform Infrared Spectroscopy (FTIR), Scanning Electron Microscopy (SEM), Transmission Electron Microscopy (TEM) and Vibrating Sample Magnetometer (VSM) techniques. The imprinted polymers showed much higher adsorption capacity towards the analyte (Kd = 12,059.5 mL g−1) than the magnetic non-imprinted polymers (MNIPs) (Kd = 962.2 mL g−1). Adsorption data fitted well into linearized Freundlich equation (R2 = 0.981) and followed pseudo-second-order kinetic model (R2 = 0.999). Scatchard plot analysis revealed heterogeneous binding sites on MMIPs while it was homogenous on MNIPs. Polymers were highly selective in extracting chlorpyrifos even in the presence of its structural analogue quinalphos (α = 16.2) and triazophos (α = 15.6). Imprinted polymer after regeneration was successfully used three times for rebinding the template without any apparent loss in adsorption capacity. Using prepared polymers, about 86.23–92.04% and 89.42–102.36% of the chlorpyrifos were successfully recovered from fortified market samples of honey and brinjal with relative standard deviation of 1.70–3.93% and 0.17–5.50%, respectively.