The use of modified electrode with carbon black as sensor to the electrochemical studies and voltammetric determination of pesticide mesotrione

A new, simple, sensitive and fast analytical method has been developed for the quantification of the pesticide mesotrione (MST) using square-wave voltammetry (SWV) and a modified glassy carbon electrode with carbon black (CB/GCE) in the presence of the cationic surfactant cetyltrimethylammonium bromide (CTAB). MST exhibited three well-defined irreversible reduction peaks, at -242, -710 and -1105 mV (vs. Ag/AgCl (3.0 mol L-1 KCl)), by cyclic voltammetry in phosphate buffer solution (pH 2.0) containing 30.0 mu mol L-1 CTAB. An electrocatalytic effect was observed for the first peak; the apparent heterogeneous electron-transfer rate constant (k) obtained using electrochemical impedance spectroscopy for a 5.0 mmol L-1 K-3[Fe(CN)(6)]/5.0 mmo lL(-1) K4IFe(CN)(6)] (1:1) solution was 9.77 x 10(-3) cm s(-1), almost two orders of magnitude greater than the rate constant obtained for the GCE electrode (2.15 x 10(-4) cm s(-1)). The analytical curve for MST was linear in the MST concentration range from 0.040 to 7 2 [mu mol L-1 with a limit of detection of 0.026 mu mol L-1. This method was used to determine MST concentration in natural lake and tap water samples and in a sugarcane juice sample, with satisfactory results. (C) 2017 Elsevier B.V. All rights reserved.