Fate of Pesticide Metabolites on Malt During Brewing

摘要

The fate of fungicidally active metabolites of triadimefon and tri-flumizole during brewing was studied to estimate their risk of carryover into beer. The water-solubilities of these metabolites, determined from previous studies or a high-performance liquid chromatography retention time index experiment, were greater than those of their parent compounds. This indicated a higher possibility of carryover into beer than that for their parent compounds. A highly sensitive and selective analytical method for the determination of pesticide metabolite residues in wort or beer using liquid chromatography-tandem mass spectrometry (LC-MS/MS) was developed. The metabolites of triadimefon and triflumizole were spiked onto ground malt at a concentration of 1,000 μg/kg. The malt was mashed, and the wort was boiled with hop pellets and fermented on a laboratory scale. The metabolite residues in sweet wort, boiled wort, and young beer were determined. The carryover percentages into sweet wort against the amount spiked on malt were 36% (triadimefon metabolite) and 19% (triflumizole metabolite). These carryovers were close to the calculated levels, expected from their partition coefficients between n-octanol and water (P_(ow) values). The final residues of triadimefon and triflumizole metabolites in young beer were 30 and 7 μg/kg, respectively. These results indicated that the agrochemical metabolites, which have agrochemical activity and toxicity as strong as their parent agrochem-icals, persist during brewing and that residues on malt could be carried over into beer like their parent compounds.