Determination of multiclass herbicides in sediments and aquatic products using QuECHERS combined with ultra-high performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS) and its application to risk assessment of rice-fish co-culture system in China

Abstract A sensitive method for determination of nine herbicides (prometryn, acetochlor, butachlor, quinclorac, bensulfuron methyl, metsulfuron methyl, atrazine, linuron and bentazone) in sediments and muscle of aquatic products was developed and validated using QuEChERS and ultra-high performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS). The results demonstrated that the matrix-matched calibration curves for sediment and fish muscle were satisfactory linearly of a concentration (0.50 to 100 μg/L) (r > 0.999). The limit of detection (LOD) and limit of quantification (LOQ) ranged from 0.10 ~ 0.50 μg/kg and 0.50 ~ 1.50 μg/kg, respectively. The recoveries ranged from 82.94 to 114.41%, with the relative standard deviations (RSDs) lower than 13.11% for nine herbicides. Finally, the validated method was applied to detect nine herbicides in 68 rice-fish and 30 sediment samples in the rice-fish co-culture system (RFCS) in six provinces of China. The dietary and ecological risks were evaluated through a calculated hazard quotient (HQ) and risk quotient (RQ). The residues of herbicides in the paddy fish did not harm the human body (HQ