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Simultaneous determination and risk assessment of fipronil and its metabolites in sugarcane, using GC-ECD and confirmation by GC-MS/MS

Biswas, Subrata, Mondal, Rahul, Mukherjee, Ayan, Sarkar, Mitali, Kole, Ramen Kumar
Food chemistry 2019 v.272 pp. 559-567
algae, detection limit, earthworms, fipronil, gas chromatography, half life, metabolites, risk, soil, sugarcane
A sensitive gas chromatographic method using a modified QuEChERS technique is reported for simultaneous determination, dissipation and risk assessment of fipronil and its metabolites in sugarcane and soil. Recoveries were 80.7–98.5% with precision within 1.4–16.5% estimated at the limits of detection (LOD) 0.0015–0.002 µg g−1 and limits of quantification (LOQ) 0.005 µg g−1. Fipronil dissipated with half-life (T1/2) of 2.8–4.3 days while for total fipronil it was 3.7–6.0 days following application of fipronil (5% SC) in sugarcane fields at recommended (100 g a.i. ha−1) and double the recommended (200 g a.i. ha−1) doses. Estimated pre-harvest intervals (PHI) for fipronil were 20.3–27.0 days in sugarcane plants, and for total fipronil the corresponding values were 28.2–37.8 days. No dietary risk was observed due to fipronil (RQd < 1) 5 days after application. Potential risk exists towards algae and soil macro-organism (RQs > 1), but for earthworms it was safe (RQs < 1).