Desenvolvimento de método por extração em fase sólida para a determinação de resíduos de pesticidas em cachaça por cromatografia líquida/espectrometria de massas

Abstract

Cachaça is the third most consumed distilled beverage in the world, with a Brazilian production of approximately 1.6 billion liters per year. Sugarcane is susceptible to the harmful action of different pests during its cultivation, motivating the use of pesticides. The use of these substances can leave residues in sugarcane, as well as in cachaça and, knowing their potential harmful to consumer health, demands monitoring of residues in the final product. Given this context, the present work aimed to develop a method for the determination of pesticide residues in cachaça, applying solid phase extraction as an extraction method and liquid chromatography/mass spectrometry as an instrumental technique for the determination of 2,4-D, abamectin, acetamiprid, alachlor, ametryn, atrazine, azoxystrobin, carbofuran, clothianidin, diuron, epoxiconazole, flutriafol, imidacloprid, lufenuron, pendimethalin, pyraclostrobin, simazine, teflubenzuron, thiacloprid, thiamethoxam and triadimefon. The best extraction conditions were obtained with a previous sample dilution step, 0.5 g of C18 conditioned with dichloromethane, methanol and water (5 mL each) and 5 mL of ethyl acetate for extraction. The method was linear for the 21 pesticides in the concentration range of 0.25 – 50 µg L-1 (r² >0.99); selective with matrix effect ranging from 0 – 31%; accurate (between 49 – 124%, RSD ≤ 19%) and precise (RSD repeatability ≤ 19% and intermediate precision RSD ≤ 18%). The detection (LD) and quantification (LQ): LDm limits were between 0.14 – 3.65 µg L-1 ; LQi 0.58 - 21.42 µg L-1 ; LQm 5 and 40 µg L-1 respectively. The method was applied to 10 commercial cachaça samples, all of which showed the presence of pesticides. The pesticides acetamiprid, ametrine, azoxystrobin, carbofuran, diuron, epoxiconazole, flutriafol, lufenuron, pyraclostrobin, thiacloprid, thiamethoxam and triadimefon were detected in one or more samples evaluated.