Análise de clorpirifós em laranja: otimização, validação e aplicação do método

Abstract

Due to the large increase in pests in animals, crops and plantations, there was a need to implement the use of chemical substances to help control insects, fungi and weeds. Brazil is the largest consumer of pesticides in the world since 2008, becoming hostage to an agrarian food production system, raising public health problems, as estimates show that Brazilians consume about 7 kg of pesticides per year. per capita per year, making its individual and collective impact particularly worrying. Oranges had their popularity in part due to the high levels of vitamin C, and in the analyzes carried out by the National Health Surveillance Agency (ANVISA), with data published in the last report of the Pesticide Residue Analysis Program (PARA) (Cycle 2017 and 2018) released in 2019, chlorpyrifos was detected in 8.12% of these orange samples. Still on orange, four pesticides were detected irregularly, that is, they are not allowed for this crop, such as carbofuran, 2,4 D, boscalid and cyromazine. Chlorpyrifos is an extremely toxic pesticide and its concentration in orange cannot exceed 2 mg Kg-1. It is currently undergoing a reassessment of its use in Brazil, since it has already been banned in most countries where it was used. In this sense, to analyze the oranges from the city of Itumbiara-Go, the optimization and validation of the liquid solid extraction method with low temperature partition (LLE-LTP) was carried out. The method proved to be effective, given that all parameters analyzed, such as selectivity, linearity, precision, accuracy, limit of detection and quantification, were within the limits allowed for validation of analytical methods. The method showed accuracy, showing recovery percentages above 90% and below 120%, with precision below RSD ≤ 20%. After optimization and validation, oranges were collected from four different points and submitted to the optimized method. After the analyzes using the High Performance Liquid Chromatography method, it was found that only one sample of the oranges was contaminated with the pesticide chlorpyrifos at a concentration of 2.83 mg/kg-1, a concentration above the Maximum Residue Limit allowed , which is a worrying factor due to its consequences for human health and the environment.