Determinação de Mancozebe em defensivos agrícolas utilizando eletrodo de diamante dopado com boro (DDB) e análise por injeção em batelada (BIA) com detecção amperométrica

Abstract

The Mancozeb is a fungicide belonging to the class of dithiocarbamates (DTCs) widely used in agriculture and non- systemic fungicide controlling a wide variety of fungi in crops of rice, potato, tomato, and citrus. Nowdays, the agrochemical industries quantify the content of Mancozeb in their commercial products using iodometric titration. The biggest drawback of this methodology is the analysis time (about two hours and thirty minutes), which causes downtime, hand labor and idle delays in approving the final product, creating problems in the flow of production and delays in delivery. This work presents the aplication electroanalytical method for the determination the fungicide Mancozeb in pesticides using boron-doped diamond electrode (BDD) and batch injection analysis (BIA) with amperometric detection. Studies regarding the choice of the electrolyte (phosphate solution pH 9.0) and potential applied (+0.3 V) were performed. And, the BIA system parameters such as injection rate and injected volume were optimized. Regarding the quantification of Mancozeb, an analytical curve with a detection limit of 5.14x10-7 mol L- 1 and limit of quantification 1.71x10-6 mol L- 1 was obtained. Interfering studies were performed and yielded recovery coefficients between 88.70 and 108.7 %. The content of mancozeb was determined in samples of pesticides with relative error lower than 1.85 %, another advantages associated to the developed method is high analytical frequency (90 injections per hour).