Desenvolvimento de um método analítico utilizando microextração por sorvente empacotado (MEPS) e HPLC-UV para determinação dos agrotóxicos diuron, parationa metílica e clorotalonil em sucos de frutas

Abstract

Agricultural productivity is directly linked to the application of pesticides in crops and their large- scale use increases the probability of residues in various matrices, which due to their harmful effects, are a risk to the entire ecosystem. One of the main sources of human contamination by pesticides is food, which makes it necessary to continuously assess the levels of pesticide residues in this matrix, in order to identify the quality of the food and estimate human exposure to these harmful compounds. Among several foods, fruit juice stands out for being a tasty and very nutritious drink, being a food appreciated by the entire age group of the world population, in this way, the objective of this work was to develop and validate an analytical method using microextraction in packed sorbent (MEPS) and HPLC-UV for the determination of diuron, methyl parathion and chlorothalonil pesticides in apple, strawberry, pineapple, grape and cashew juices. MEPS is a sample preparation technique where the sample extraction, pre-concentration and cleaning steps take place in a single device that operates in microliters, which allows for the automation of the system and the development of methods with low solvent consumption. sample and sorbent. For the development of the method proposed in this work, apple juice was used as a representative matrix and eight factors that affect the performance of the MEPS technique were evaluated. The optimal conditions for the developed method provided high extraction and pre-concentration efficiency, greatly increasing the detectability of pesticides in the HPLC-UV, in addition to providing the reuse of the C18 sorbent for more than 70 times without loss of efficiency in the extraction, reaching values above 18.2 for the concentration factor. The results of the analytical validation, using the representative matrix (apple juice), met the acceptability criteria of ANVISA and the European Commission, where the LOD ranged from 0.0010 and 0.0015 mg L-1 , the LOQ from 0.0050 and 0.0100 mg L-1 and the linear range for the three pesticides included the LOQ concentration of each compound up to 1.0000 mg L-1 , meeting the concentrations established for MRL by the legislation for pesticides in food. Method recovery ranged from 87.5% to 112.2%, with RSD ≤ 11%. To consolidate the analytical validation, additional tests were performed for all matrices studied, with recovery results ranging between 67.0% and 119.6% and RSD ≤ 20.2%, considering the acceptance criteria of the validation protocols.