Simultaneous Electroanalytical Determination of Thiram and Carbendazim in Samples of Fresh Fruit Juices in the Presence of Surfactants

This study describes a new simple electrochemical method, with high sensitivity and selectivity to simultaneously quantify both thiram (THI) and carbendazim (MBC) pesticides in samples of apple, banana, peach, and strawberry juices, using carbon paste electrode modified with thermally activated zeolite in the presence of surfactants. Differential pulse voltammograms obtained for THI and MBC indicated irreversible behavior at approximately 700 mV and 800 mV (vs. Ag/AgCl (3 mol L-1 KCl)), respectively, when the anionic surfactant was present in the electrochemical cell. Values of peak oxidation currents exhibited linear correlations in the concentration ranges 3.44-1,000 and 1.72-350 ng mL(-1) for THI and MBC, respectively. Limits of detection and quantification were estimated by obtaining the values 1.01 and 0.51 and 3.38 and 1.67 ng mL(-1) for THI and MBC, respectively. After the sample contamination, recoveries were obtained between 98.6% and 101.8%. Values of relative standard deviation obtained in the stability, repeatability, precision, and selectivity studies were lower than 2% for both pesticides. Recoveries obtained with the proposed methodology showed high conformity with the results obtained using high-performance liquid chromatography (HPLC).