Dissipation dynamics of fenamidone and propamocarb hydrochloride in pepper, soil and residue analysis in vegetables by ultra-performance liquid chromatography coupled with tandem mass spectrometry

摘要

In this study, a rapid and sensitive method was developed for determining fenamidone and propamocarb hydrochloride residues in vegetables and soil by ultra-performance liquid chromatography-tandem mass spectrometry. The dissipation dynamics of fenamidone and propamocarb hydrochloride in pepper and soil was investigated in Beijing, Henan and Shandong provinces. The target compounds were extracted with methanol and cleaned with dispersive solid phase extraction using primary secondary amine. Two pairs of precursor product ion transitions for fenamidone and propamocarb hydrochloride were measured and evaluated. Average recoveries of fenamidone in potato, tomato, cabbage, pepper and soil at three levels (10, 100 and 1000 g kg(-1)) ranged from 76.91% to 107.31% with relative standard deviations (RSDs) from 2.74% to 10.87% (n=15). The average recoveries of propamocarb hydrochloride ranged from 74.84% to 97.96% with RSDs from 2.43% to 16.16% (n=15). The limits of detection (LODs) for fenamidone in each matrix were 0.131-0.291 g kg(-1), and the limits of quantification (LOQs) were 0.436-0.970 g kg(-1). The LODs for propamocarb hydrochloride were 0.125-0.633 g kg(-1), and the LOQs were 0.417-2.11 g kg(-1). The results also showed that the dissipation of fenamidone and propamocarb hydrochloride in pepper and soil followed first-order kinetics model more than that of bi-exponential models. The half-lives of propamocarb hydrochloride were 6.90-15.78days in pepper and 13.56-23.02days in soil. The half-lives of fenamidone were 7.48-11.29days in pepper and 35.18-42.78days in soil.