Dissipation, residues analysis and risk assessment of metconazole in grapes under field conditions using gas chromatography-tandem mass spectrometry

Metconazole (MEZ) is widely used in prevention and control of fruit and vegetable diseases. Here, a simple and reliable gas chromatography-tandem mass spectrometry (GC-MS/MS) method, using modified QuEChERS (quick, easy, cheap, effective, rugged and safe) extraction method, was developed for determining the dissipation and residue of MEZ in grapes and soil, and the dietary risk of MEZ residues in grapes was evaluated for Chinese people. The average recoveries of MEZ in two matrices were 80.72-100.36% with relative standard deviations of 1.56-6.16%. The same limits of detection and quantification in grapes and soil were 0.0006 mg/kg and 0.002 mg/ kg, respectively. Under field conditions, the half-life of MEZ dissipation in grapes ranged from 11.75 to 20.39 days. The final residues of MEZ in grapes and soil ranged from 0.002 mg/kg to 0.19 mg/kg at pre-harvest intervals of 7, 14 and 21 days. The whole dietary risk assessment indicated acute hazard index and hazard quotient to be less than 1, implying the risk of MEZ was acceptable. This is the first study conducted on the dissipation, residue analysis and risk assessment of MEZ in grapes, thus providing reference for the detection and risk assessment of MEZ in other agricultural products.

Automated summary

A GC-MS/MS method was developed to determine the dissipation and residue of MEZ in grapes and soil, and assess the dietary risk for Chinese people. The study found that the half-life of MEZ in grapes ranged from 11.75 to 20.39 days, and the overall risk assessment indicated that the risk of MEZ was acceptable. This study provides valuable reference for the detection and risk assessment of MEZ in other agricultural products.