Optimization and validation of bifenazate and bifenazate-diazene quantification in agricultural products using a reduction method

Abstract Bifenazate is a widely used insecticide for mite control and readily oxidizes to bifenazate-diazene, which can revert to bifenazate under mild reducing conditions. This study aimed to develop a reliable method for quantifying bifenazate in agricultural products by optimizing the reduction conditions for bifenazate-diazene and evaluating the purification efficiency of different sorbents. Ascorbic acid was employed as a reductant, and four sorbents (PSA, PSA + C18, PSA + C18 + GCB, and Z-Sep +) were tested for matrix effects and recovery in pepper, mandarin, and brown rice. The optimal reduction conditions were determined to be 50 °C for 1 h, ensuring nearly complete conversion of bifenazate-diazene. Among the adsorbents, Z-Sep + demonstrated the lowest matrix effect and the highest recovery for bifenazate, followed by PSA + C18 and PSA. Considering the balance between matrix effects and recoveries across the three tested agricultural commodities, we optimized the analytical method using Z-Sep + as the primary purification sorbent. The developed method was validated for selectivity, linearity ( R 2 > 0.999), accuracy, and precision, meeting international regulatory guidelines. While this study primarily focused on common agricultural matrices, future research is needed to evaluate the method’s applicability to a wider range of agricultural products, including those with complex matrices such as high-fat and high-protein foods, as well as its performance in real-world agricultural samples.