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The residue behavior and dietary intake risks of carbosulfan and its metabolites in cucumbers were investigated. A quick and reliable method for determining carbosulfan and its metabolite residues in cucumbers was established using ultrahigh performance liquid chromatography–tandem mass spectrometry. The fortified recoveries ranged from 87.2% to 91.0% with relative standard deviations of 3.2%–8.1%. The dissipation results showed that carbosulfan was transformed into carbofuran and 3-hydroxy carbofuran in cucumbers. The half-life of carbosulfan was 1.5 days, and the half-life of carbofuran was 45 days. The final residues of carbosulfan varied from 0.245 to 0.005 mg/kg and carbofuran varied from 0.123 to 0.008 mg/kg. After a 5-day application period the residues of carbosulfan was 0.113 mg/kg that was below the maximum residue limit set by China (0.2 mg/kg), and the residues of carbofuran was 0.055 mg/kg that was higher than the maximum residue limit set by China (0.02 mg/kg). The risk assessment results indicated that the dietary intake risks of carbosulfan and carbofuran from cucumber consumption were safe for Chinese consumers, but pre-harvest intervals should be strictly recommended for 7 days at the recommended dose to ensure that food quality conforms to the MRL standard. This study provides a method and data for scientifically evaluating dietary intake risks of carbosulfan and its more toxic metabolites. [ABSTRACT FROM AUTHOR]

BACKGROUND The residue concentrations and dissipation rate of a new oxathiapiprolin fungicide in grapes and soil were investigated to provide an evaluation for the safe use of oxathiapiprolin in grapes. Pesticide residue was extracted by acetonitrile, then purified by solid-phase extraction with an Envi-Carb cartridge and determined by ultrahigh-performance liquid chromatography-tandem mass spectrometry. RESULTS The fortified recoveries ranged from 85.2% to 99.0%, with relative standard deviations of 1.7-4.5%. The limit of quantitation for oxathiapiprolin in grapes and soil was 0.002 mg kg−1. The mean initial deposits of oxathiapiprolin in grapes were 0.345-0.565 mg kg−1, with half-lives of 8.6-9.2 days. The mean initial deposits of oxathiapiprolin in soil were 0.078-0.273 mg kg−1, with half-lives of 7.6-12.0 days. The oxathiapiprolin residue in grapes and soil was 0.002-0.022 mg kg−1 and 0.002-0.123 mg kg−1 when sampling 14 days after application, respectively. CONCLUSION The residue in the grapes was less than 0.01 mg kg−1 when sampling 28 days after application, which suggested that the application rate of 20 mg a.i. kg−1 for this fungicide should be used to ensure that treated grapes can be considered safe for humans to consume when sampling 28 days after the final application. © 2016 Society of Chemical Industry [ABSTRACT FROM AUTHOR]

The residue behavior and dietary intake risk of three fungicides (pyrimethanil, iprodione, kresoxim-methyl) in tomatoes ( Lycopersicon esculentum Mill.) grown in greenhouse were investigated. A simple, rapid analytical method for the quantification of fungicide residues in tomatoes was developed using gas chromatography coupled with mass spectrum detection (GC-MSD). The fortified recoveries were ranged from 87% to 103% with relative standard deviations (RSDs) varied from 4.7% to 12.1%. The results indicated that the dissipation rate of the studied fungicides in tomatoes followed first order kinetics with half lives in the range of 8.6–11.5 days. The final residues of all the fungicides in tomatoes were varied from 0.241 to 0.944 mg/kg. The results of dietary intake assessment indicated that the dietary intake of the three fungicides from tomatoes consumption for Chinese consumers were acceptable. This study would provide more understanding of residue behavior and dietary intake risk by these fungicides used under greenhouse conditions. [ABSTRACT FROM AUTHOR]

A new combined difenoconazole and fluxapyroxad fungicide formulation, as an 11.7 % suspension concentrate (SC), has been introduced as part of a resistance management strategy. The dissipation of difenoconazole and fluxapyroxad applied to apples and the residues remaining in the apples were determined. The 11.7 % SC was sprayed onto apple trees and soil in Beijing, Shandong, and Anhui provinces, China, at an application rate of 118 g a.i. ha, then the dissipation of difenoconazole and fluxapyroxad was monitored. The residual difenoconazole and fluxapyroxad concentrations were determined by ultrahigh-performance liquid chromatography tandem mass spectrometry. The difenoconazole half-lives in apples and soil were 6.2-9.5 and 21.0-27.7 days, respectively. The fluxapyroxad half-lives in apples and soil were 9.4-12.6 and 10.3-36.5 days, respectively. Difenoconazole and fluxapyroxad residues in apples and soil after the 11.7 % SC had been sprayed twice and three times, with 10 days between applications, at 78 and 118 g a.i. ha were measured. Representative apple and soil samples were collected after the last treatment, at preharvest intervals of 14, 21, and 28 days. The difenoconazole residue concentrations in apples and soil were 0.002-0.052 and 0.002-0.298 mg kg, respectively. The fluxapyroxad residue concentrations in apples and soil were 0.002-0.093 and 0.008-1.219 mg kg, respectively. The difenoconazole and fluxapyroxad residue concentrations in apples were lower than the maximum residue limits (0.5 and 0.8 mg kg, respectively). An application rate of 78 g a.i. ha is therefore recommended to ensure that treated apples can be considered safe for humans to consume. [ABSTRACT FROM AUTHOR]