Milad Ghani, Seyedeh Bentolhoda Hosseinian, Behrooz Maleki, Pouya Ghamari Kargar
• PAMAM-SH@Fe 3 O 4 was used for the MSPE of organophosphorus pesticides. • The method can be directly used in relatively complicated samples. • PAMAM-SH@Fe 3 O 4 showed high extraction performance, high stability and easy preparation. • The method is sensitive, cost-effective, and has wide LDRs and low LODs. Herein, polyamidoamine-SH dendrimer@Fe 3 O 4 (PAMAM-SH@Fe 3 O 4 ) was synthesized using a simple, green, fast, cost-effective, and efficient method. Firstly, polyamidoamine dendrimer with SH terminal groups (PAMAM-SH) was prepared by the Michael addition method. Subsequently, PAMAM-SH was immobilized on the surface of Fe 3 O 4 nanoparticles. The proposed PAMAM-SH@Fe 3 O 4 material exhibits superior extraction efficiency compared to conventional sorbents due to its abundant functional groups and thiol modifications, enabling highly effective MSPE of organophosphorus pesticides in complex matrices. The obtained PAMAM-SH@Fe 3 O 4 nanocomposite was utilized as a sorbent for magnetic solid-phase extraction (MSPE) of four selected organophosphorus pesticides (OPPs), including diazinon, malathion, chlorpyrifos, and phosalone. The extracted analytes were desorbed using methanol (as the appropriate eluent) and analyzed by high-performance liquid chromatography with ultraviolet detection (HPLC-UV). Under optimized condition, the method exhibited good linearity in the range of 0.10–500.00 µg L⁻¹ for the target analytes (corresponding coefficients of determination (R²) > 0.9923). The limits of detection (LODs) and quantification (LOQs) were in the ranges of 0.02–0.13 µg L⁻¹ and 0.08–0.42 µg L⁻¹, respectively. Inter- and intra-day relative standard deviations (RSDs) were between 1.60% and 5.90%. The enrichment factors (EFs) were determined to be 79.00, 84.00, 72.00, and 81.00 for diazinon, malathion, chlorpyrifos, and phosalone, respectively. The proposed method was successfully applied to real samples, including apples, pears, peaches, grapes, and agricultural wastewater, demonstrating its reliability and applicability for complex matrices.