Desenvolvimento de métodos para determinação de agrotóxicos em tecidos adiposo e hepático de anuros empregando extração QuEChERS miniaturizada

Abstract

The use of pesticides in various cultures to combat plagues and diseases has always been a factor that required prudence and monitoring, but its use has been intensifying over the last few decades. Despite some immediate advantages in pest control, its use on a large scale has caused major disturbances and changes in the environment, such as soil and water contamination and risk of contamination of non-target species. Indirect contamination of many animal species such as frogs can lead to decreased growth, increased abnormalities, and, in some cases, lead to death. However, to assess the presence of these compounds in anurans, an invasive step of removing part of the animal's tissue is necessary. Thus, in this work, two methods for the determination of pesticide multiresidues in tissues, that mimic those of anurans (adipose and hepatic chicken tissue), were developed for the analysis of pesticide contamination of anuran tissues. The pesticides selected for the study were chlorpyrifos, cypermethrin, endosulfan, and atrazine. The selected extraction method was the QuEChERs combined with high-performance liquid chromatography coupled to the photodiode array detector, as a technique for separating and quantifying the pesticide residues. The QuEChERS were miniaturized to significantly reduce the amounts of samples, solvents, salts, and cleaning sorbents obtaining more economical and high recovery efficiency methods. Some QuEChERS conditions were optimized, such as solvent extractor, mass of salts to promote the salting-out effect, and cleaning sorbents. The solvent that showed the best recovery percentages was acetonitrile, for both matrices. The cleaning step was not relevant for the adipose tissue samples, but it was essential for the liver tissue ones. After optimizing the extraction method for both matrices, the method was validated following the European Community validation guide, SANTE/12682/2019 document. Thus, the proposed method was able to extract, separate, and quantify pesticides in complex samples such as adipose and hepatic tissue from chickens with LOQ range from 0.01-0.07 mg L-1, indicating that the method has good detectability, being able to evaluate the presence of pesticide residues in low concentrations in the anuran tissues.