Multivariate Optimization of the QuEChERS-GC-ECD Method and Pesticide Investigation Residues in Apples, Strawberries, and Tomatoes Produced in Brazilian South

Apple, strawberry and tomato are among the foods with higher contamination for pesticide use in Brazil. Thereby, a multivariate optimization of the QuEChERS method coupled to GC-ECD was proposed to investigate the level of pesticides residues clorpyrifos, dimethoate, malathion, mevinphos, pedimentalina, simazine and trifluralin in apple, strawberries and tomatoes produced in Santa Catarina state, South of Brazil. The process involved a two-level full factorial and Doehlert designs followed by validation of the modified method and its application in 91 real samples collected during the years 2010 and 2011. Modifications in the method provided increased detectability and satisfactory values of linearity, accuracy and precision. In real samples, residues of at least one pesticide (> LOQ) were found in 8 (27.6%) apple, 12 (40.0%) strawberry and 17 (53.1%) tomato samples. The results indicated the necessity of continuous monitoring for pesticide use in fruits and vegetables.