Spectroscopic Characterization, Quantification, and Health Risk Estimation of Chlorpyrifos Residues in Maize Kernels

Abstract Chlorpyrifos, a common organophosphate insecticide used in maize production, nonetheless, there are rising concerns about its safety and human health. In this study, chlorpyrifos residues in maize kernels from Bahir Dar, Northwest Ethiopia, were examined using Ultraviolet-Visible (UV/Vis) spectroscopy. The method identified the stable decomposition product 3,5,6-trichloro-2-pyridinol (TCP) at 485 nm, using the volumetric optimization of alcoholic KOH, Cong red, and HNO 3 solutions and the physical parameters such as temperature, pH, and time. The calibration curve with a series of chlorpyrifos standard solutions obeyed Beer’s Law with an excellent linearity range of 0.01-1.0 µg/mL (R 2  > 0.99). TCP levels in maize from Bahir Dar city ranged from 0.000 to 0.024 µg/mL (mean 0.003 µg/mL, detection rate ≥ 7%), while Dangla district samples ranged from 0.004–0.052 µg/mL (mean 0.014 µg/mL, detection rate ≥ 42%). The average TCP level of the collected samples was 0.01 µg/mL, below t he Codex maximum residue limit (MRL). Estimates of the percentages of ARfD and HQc in all adults were less than 1; the health risks of dietary exposure to TCP in the adult population were acceptable. Our findings highlighted that enhancing pesticide field monitoring is essential for guaranteeing food safety and guiding the rational use of pesticides. Therefore, UV/Vis spectroscopic pesticide analysis is a low-cost, accurate, rapid, and reliable detection method for pesticide residues in food and environmental samples.