Uso de SPE e LC-MS na determinação de resíduos de pesticidas de 12 grupos químicos em cerveja pilsen utilizando biocarvão como um promissor material adsorvente

Abstract

Beer is the third most consumed alcoholic beverage in the world and to provide a lighter flavor, many brewers use adjuncts such as corn and rice to replace or complement barley during the malting process. On the other hand, as a way of accelerating the production of these cereals and eliminating pests that affect production, pesticides are used that can remain in the cereals until the final product, beer, is obtained. Theses pesticides can harm consumer health. Thus, this work aimed to develop a method for the determination of pesticide residues in Lager Pilsen beer. For this, the solid phase extraction technique was used in order to prepare the sample and isolate the analytes. Then the liquid chromatography/mass spectrometry technique was used to identify abamectin, acetamiprid, ametryn, atrazine, azoxystrobin, carbendazin, carbosulfan, chlorpyrifos, deltamethrin, diuron, esfenvalerate, epoxiconazole, flutriafol, haloxyfop, lufenuron, malation, propanil, terbuphos, thiamethoxam, thiophanatemethyl and simazine. Commercial adsorbents were tested: sílica, florisil, PSA (primary and secondary amine), neutral alumina and C18, in addition to alternative adsorbents: corn cob biochar, water hyacinth biochar and grape seed biochar. As well as metanol, acetonitrile, ethyl acetate and mixture of metanol and dichloromethane in diferente proportions used as extraction solvent. The best results for the commercial adsorbent were using the conditions of 150 mg of C18, 10 mL of sample with a fortification level of 1 µg mL-1 and 3 mL of methanol and dichloromethane (90:10) and for the alternative adsorbent 150 mg of water hyacinth biochar, 10 mL of sample with a fortification level of 1 µg mL-1 and 3 mL of methanol and dichloromethane (60:40) as elution solvente. The method was validated with hyacinth biochar and showed linear r2 > 0,99, exact, precise (repeatability ≤ 19 % and intermediate precision ≤ 9%). The detection limit was between 0,009 – 0,03 µg mL-1 and the quantification limit was between 0,02 – 0,1 µg mL-1. The method was applied to 13 beer samples, but no residues of the studied pesticides were detected under the conditions established for the method.