Development and validation of quantitative NMR method for illegal pesticides

Since the 1950s, the consumption of agrochemicals has increase disorderly in Brazil. In this way, the smuggling of these products has also increased exponentially. According to the Brazilian’s Federal Police report, in 2016 the increase of pesticides smuggling was aroud 188% in relation to 20151. However, smuggled agrochemicals showed characteristics unknown from the chemical, physical and biological point of view. Thus, these products should be characterize. The qNMR is a simple, fast and non-destructive methodology that allows a simultaneous qualification and quantification of various substances (target and non-target)2. Therefore, the objective of the present work is to develop and validate a quantitative method by 1H NMR for analysis of smuggled agrochemicals seized by the Federal Police. The validation was performer according to ABNT NBR 14029: 2016 and the Association of Official Analytical Chemists (AOAC) using standards of azoxystrobin, imidacloprid, λ-cyhalothrin, tebuconazole and thiamethoxam, which were determinate simultaneously. All analyzes were performed on a Fourier300 Bruker NMR equipment, using CDCl3 as solvent. To verify the method viability, there were tested 08 commercial samples as well as 02 products seized. The mean validation results are show in Table 1. About analyzes of the commercial pesticides, all showed the amount of active principle specified by the manufacturer. However, the smuggled products presented difference ranging 20-26% less than the concentration specified. Thus, the method developed is applicable to identify the active principles of commercial pesticides as well as to differentiate between those seized.