Microextração em fase sólida molecularmente impressa de triazóis em amostras de água e suco de uva seguido de análise por GC-MS

Abstract

The use of pesticides in agriculture is a major source of environmental contamination since such compounds are leached and disseminated in surface water, groundwater and soil water, making it a problem for fauna, flora and human health. Moreover, pesticide residues are frequently found in food due to their uncontrolled use. Thus, it is necessary to develop analytical techniques of sample preparing for both pesticide extraction and concentration in water resources as well as food. Among these techniques, we can highlight the molecularly imprinted solid phase micro extraction (MISPME), due to its particular advantages as high selectivity, low organic solvent consumption, low extraction time, low cost of fiber fabrication, among others. Therefore, the present study's aim is to synthesize and characterize a new fiber for MISPME to extract triazoles from environmental and food samples followed by GC/MS analysis. According to MAPA (Ministry of Agriculture and Livestock) MRLs for grape triadimenol, tebuconazole, epoxiconazol and metconazole are respectively 0.1 mg kg-1, 2 mg kg-1 prohibited to grape culture and 1 mg kg-1. Knowing that epoxiconazole is prohibited to grape culture, it was selected as internal standard. The tolerance limit in water is established by international organizations, such as tolerance embrace a concentration of 0.1 mg L-1 for each pesticide and 0,5 mg L-1 for a total of them. For grape juice analysis, the analytical range of the method comprises from 100 μg L-1 to 2000 μg L-1 to triadimenol, tebuconazole and metconazole, with LQ of 100 μg L-1. For water analysis, the analytical range of the method comprises from 100 μg L-1 to 3000 μg L-1, with LQ of 100 μg L-1.The proposed method for triazole analyses in grape juice met all required specifications being applied with confidence. However, the detectability of the method was insufficient for the analyses of triazoles in water samples due to the low tolerance limits.