The fate of during brewing of pesticides (organic compounds and copper) from hops was determined to reveal linkages between various pesticide sequences applied in hop yards and the level of pesticides in beer. For this purpose, laboratory-scale brewing trials were carried out with conventional hops from four localities in which pest control spray programs varied. Pesticide residue analysis in samples of hopped wort, young beer, and beer was carried out by liquid chromatography in tandem with mass spectrometry (LC-MS/MS). Cu concentrations were determined using inductively coupled plasma mass spectrometry (ICP-MS). The transfer rates (%) of individual pesticides were calculated to demonstrate their ability to be transferred from hops to the brewed solutions. The pesticides exhibited different transfer rates correlating well with their log p values; however, the obtained transfer data were not related to their concentration in hops. The average transfer rates calculated for ametoctradin (15% ± 5%), mandipropamid (38% ± 4%), boscalid (48% ± 5%), and azoxystrobin (47% ± 2%) increased in good correlation with their descending log P values. On the contrary, the transfer rates of copper residues were related to residual concentrations of copper in hops and exhibited logarithmic dependency. The carryover of the sum of all pesticides in the four samples ranged from 36% to 49%, averaging 42% ± 6%. The data showed no substantial influence of various pesticide spray sequences on the percentages of overall pesticide residues carried over into beer.
Keywords: LC-MS/MS; Pesticide residues; beer; copper; hops; laboratory scale brewing trials.