Selective Solid-Phase Extraction and Determination of Profenofos from Food and Water Samples Using Surface Molecularly-Imprinted Bentonite

Abstract

In this study, a surface-imprinted molecularly imprinted polymer (MIP) was prepared on bentonite (BNT) to create a selective solid-phase extraction (SPE) sorbent for detecting profenofos (PFF), a commonly used organophosphorus pesticide. The MIP-BNT material was produced through surface-initiated free-radical polymerization, and structural analyses confirmed the presence of specific binding sites, uniform morphology, and an enhanced surface area. Adsorption behavior followed a pseudo-second-order kinetic model (R2= 0.9965), while equilibrium data showed strong agreement with the Langmuir isotherm (R2= 0.9979), indicating monolayer adsorption. Key SPE parameters-including pH, sorbent amount, desorption time, and eluent volume-were systematically optimized. The final conditions (pH 6.0, 10 mg sorbent, 25 min desorption, 150 mu L eluent) ensured high recovery and repeatability. When coupled with UV-vis spectrophotometry, the optimized MIP-SPE method provided a wide linear range (0.1-270 mu M), a low detection limit (0.03 mu M), and stable performance over at least eight reuse cycles. Recovery experiments conducted in food and water matrices yielded values between 94.01 % and 100.42 %, with RSD values below 5 %, and results were consistent with HPLC measurements. Overall, the developed approach presents a selective, cost-effective, and environmentally friendly alternative for routine PFF analysis.