Development of dummy template molecularly imprinted polymer adsorbent to extract organophosphorus pesticides from vegetables

Abstract

In this study, a highly selective adsorbent based on a dummy-template molecularly imprinted polymer (DMIP) was synthesized using diethylphosphonoacetic acid (DPA) as the template for batch adsorption method of organophosphorus pesticides (OPPs). The synthesized polymers were characterized using FTIR, nitrogen adsorption-desorption analysis, SEM, XRD and TGA. Under optimum conditions, the results showed that the sorption of DMIP was best-fitted the pseudo-second order kinetic model and the Freundlich isotherm, with maximum adsorption capacities ranging from 24.36 to 55.31 mg g⁻¹ for the selected OPPs. The thermodynamic studies established that the reactions were both spontaneous and exothermic at 298 K. The reusability study indicated that there is no substantial loss of removal efficiency while using the DMIP for up to five cycles. In addition, the developed method showed good linearity (1 – 10 mg L⁻¹) for the OPPs, with a coefficient of determination (R²) values above 0.9969. The limits of detection (LOD) and quantification (LOQ) values were respectively found to be 0.2732 – 0.3177 µg mL⁻¹ and 0.9097 – 1.0579 µg mL⁻¹, with a relative standard deviation (RSD%) of less than 4.77 % for intra-day and inter-day analysis. Based on the results obtained, the synthesized DMIP showed an excellent potential as selective adsorbent for pesticides present in food samples.