Residues determination and dietary risk assessment of dimethomorph and benthiavalicarb-isopropyl in table grape using QuEChERS and liquid chromatography tandem mass spectrometry

ABSTRACT

A simple, rapid and selective method based on liquid chromatography tandem mass spectrometry and QuEChERS was established for simultaneous determination of dimethomorph and benthiavalicarb-isopropyl residues in grape. The mean intra-day recoveries of dimethomorph and benthiavalicarb-isopropyl in grape were in the range of 91.5–103.5% at four-spiked levels. The inter-day recoveries of dimethomorph and benthiavalicarb-isopropyl in grape were 98.9% and 98.6% at spiked level of 0.5 mg kg^?1, respectively. The relative standard deviation (RSD) was lower than 8.4%, and the limit of quantitation (LOQ) was 0.01 mg kg^?1 for both fungicides. The residual behaviour of both fungicides in the grape field at two different locations was investigated using the developed and validated method. The half-lives of dimethomorph in grapes were 5.9 to 8.8 d, and that of benthiavalicarb-isopropyl were 7.9 to 11.6 d. The terminal residues of dimethomorph and benthiavalicarb-isopropyl were lower than 1.3 and 0.79 mg kg^?1, respectively. The results of dietary risk assessment showed that the risk of dimethomorph and benthiavalicarb-isopropyl was negligible to Chinese residents.