Residues, storage stability, and long-term dietary risk assessment of Xinjunan in cucumber, tomato, and citrus

Xinjunan is a novel broad-spectrum fungicide developed in China. However, its excessive use may lead to the accumulation of toxic residue and increased health risks. In the present study, a simple method using liquid chromatography-tandem mass spectrometry was established, and multiple experiments were conducted in 12 regions of China to characterise the risk assessment of Xinjunan residues in cucumber, tomato, citrus (pulp), and citrus (whole). The calibration curve was linear with a correlation coefficient (r) >0.9951. The recovery rates of Xinjunan in three crops at different spiking levels (0.01 ~ 1 mg kg−1) were 77%~102%, with a relative standard deviation of 1%~10%. The terminal residues of Xinjunan in cucumber, tomato, citrus (pulp), and citrus (whole) were below 0.033, 0.01, 0.01, and 0.041 mg kg−1, respectively. The results showed a low concentration level of Xinjunan residues in cucumber, tomato, and citrus than the recommended dosage. The Chinese dietary structure and terminal residue analysis under field conditions showed the risk quotient (RQ) of Xinjunan to be 0.044, which was significantly lower than 1, suggesting the risk to be acceptable. Overall, the results indicated that Xinjunan in these crops exhibited no significant risk for the human diet.