Development of Paraquat Pesticide Determination Methodology in Urine Samples by UHPLC-MS/MS

Abstract

In technical-scientific development, mankind has developed different ways of managing pests, diseases and weeds, increasing agricultural production impacting social, economic and environmental aspects. As major grains producer (such as corn, soybeans and beans), the Brazilian State, through the Brazilian agencies as Institute for the Environment and Renewable Natural Resources (IBAMA), the National Health Surveillance Agency (ANVISA), and the Ministry of Agriculture, Livestock and Supply (MAPA) authorize and regulate the use of different pesticides, including Paraquat, to improve and guarantee the production. However, the direct contact and long-term exposure to these substances offer environmental and occupational risks, impacting negatively on the workers, population of neighbor cultures, and environmental health. Considering the potential damages, it is of utmost importance to develop effective analytical methodologies for the biomonitoring and assessment of the level of exposure of farmers and ranchers in direct contact with pesticides. Thus, this work proposed to develop a sensitive and selective analytical method, using the ultra-high efficiency liquid chromatography technique, coupled to mass spectrometry seeking a fast and simple sample preparation for the Paraquat quantification in urine samples. To achieve this, two sample preparations were compared in terms of speed and practicality. The first method (A) used C18 silica as adsorbent to remove the non-polar interferences. The second preparation (B) consisted in direct sample dilution in acetonitrile. Both methodologies used centrifugation under refrigeration to precipitate suspended artifacts. The linearity of the Paraquat detection by the analytical methodology, developed in a HILIC column, was evaluated between 10 to 70 µg L-¹ (r²=0.9911; y=19427x+479868), enabling the matrix evaluation after applying the best sample preparation. The method developed was simple, fast, which makes it useful and efficient for toxicology laboratories routine to monitor the exposure levels of farmers dealing with Paraquat daily.