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

Abstract 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 (T 1/2 ) 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 (RQ d  1), but for earthworms it was safe (RQs