Validation, dissipation kinetics and monitoring of flonicamid and dinotefuran residues in paddy grain, straw, its processed produces and bran oil using LC-MS/MS

Flonicamid and dinotefuran are highly effective insecticides in paddy but residue persistence in crop and transmission into food and feed is unknown. This study aimed to examine initial deposits and dissipation kinetics of flonicamid and dinotefuran in paddy matrices and processed products including bran oil. The method was validated following acetonitrile extraction, dispersive solid phase clean-up and finally determination using liquid chromatography-mass spectrometry/mass spectrometry. Recoveries ranged from 76.6 to 109.7 percent for the paddy matrices tested. In a field experiment, flonicamid and dinotefuran were applied to paddy crops to study dissipation patterns. The half-lives of flonicamid and dinotefuran residues in paddy ranged from 2.0 to 3.0 days. However, at harvest time paddy grain and straw samples were found free from residues. Monitoring of residues in farm gate and market samples revealed that paddy products were not contaminated with flonicamid or dinotefuran residues.