Agrotóxicos em tecidos de peixes: otimização e validação do método micro QuEChERS e LC-MS

Abstract

Pesticides are widely used in Brazil. These compounds can reach non-target locations after their application, such as rivers and streams, and can contaminate the organisms that live there. Fish and other aquatic organisms can bioaccumulate these compounds and have a higher concentration of these substances than the environment around them. The present work aimed to optimize and validate a method, using micro-QuEChERS and LC-MS to determine 28 pesticides in fish muscle. The use of micro-QuEChERS makes it possible to analyze samples from small individuals without having to obtain a large number of fish. To optimize the method, different masses and types of salts and sorbents were tested, as well as centrifugation temperature. A composite experimental design was also carried out with a central point to multivariately evaluate three parameters in the method, namely the centrifugation temperature, the mass of NaCl and the mass of C18. The method was validated following the criteria required by ANVISA (2017) and INMETRO (2020). In this work we sought to obtain a selective, linear, precise, exact, economical and ecological method. Recovery values between 70 and 120% were obtained for 24 of the 28 pesticides evaluated. RSD values lower than 20% guaranteed the good accuracy of the method. Linearity was evaluated using the coefficient of determination (r2) and correlation (r), which were greater than 0.9 for all compounds. The LOQs of the method ranged from 1 to 20 µg kg-1. Thus, the miniaturized micro-QuEChERS methodology proposed for the determination of pesticides in fish muscle using LC-MS proved to be effective and can be applied in routine monitoring and analysis work. Subsequently, the method can be used in monitoring studies, especially on fish in the region that live in habitats where there is intense agricultural activity around them.