To evaluate dissipation dynamics and dietary exposure risk of beta-cypermethrin and azoxystrobin in Vigna unguiculata (L.) Walp.

Based on standardized field residue trials, a quantitative analysis method for beta-cypermethrin and azoxystrobin in Vigna unguiculata (L.) Walp was established, which adopted acetonitrile extraction, purification by solid-phase extraction columns or the QuEChERS method, followed by detection using gas chromatography and liquid chromatography-tandem mass spectrometry. Through this method, the dynamic changes of residues of these 2 pesticides in Vigna unguiculata (L.) Walp were obtained, and the chronic dietary intake risk was evaluated.

The mass concentration of beta-cypermethrin and azoxystrobin had a good linear relationship with the peak area in the range of 0.005–1.000 mg/L, respectively. The average recoveries at 3 different spiked levels were 86.3%–104.1%, the relative standard deviations were 0.60%–2.31%, and the limits of quantitation were 0.01 mg/kg. The residual dissipation dynamics of beta-cypermethrin and azoxystrobin in Vigna unguiculata (L.) Walp conformed to the first-order kinetic equation, and the half-lives of dissipation were 2.8 d and 2.9 d, respectively.

The risk of chronic dietary intake of the 2 kinds of pesticides for people of different genders and age groups is far less than 100%, and there is no potential risk.