Determination of 4-methylthio-3,5-xylyl methylcarbamate (methiocarb) insecticide using multi-walled carbon nanotube electrode with square wave voltammetry

Carbamates that are part of the large group of synthetic pesticides, generally used as insecticides. Carbamates act by blocking the enzyme cholinesterase. Methiocarb is member of carbamate pesticides. Acute oral LD50 value of is 20 mg kg?1.In this study, oxidation of methiocarb pesticide was investigated using different voltammetric methods on glassy carbon electrode (GCE) and multi walled carbon nanotube electrode (MWCNTE). Voltammetric behavior of methiocarb in H2SO4 solution and Britton?Robinson (B?R) buffer was investigated by square wave adsorptive stripping voltammetry (SWAdSV) and cyclic voltammetry (CV). Optimum conditions for the analytical determination were determined. Peak potentials of methiocarb (vs. Ag/AgCl) were found + 1265 mV. Experimental results indicate an excellent linear correlation between the peak current and the concentration in the range of 1.24 ? 59.1 ?g mL?1 with a correlation coefficient of 0.9995 in supporting electrolyte. The limit of detection (LOD) and limit of quantification (LOQ) were obtained as 0.37 and 1.24 ?g mL?1 for supporting electrolyte, respectively. The interference of inorganic species and other some pesticides on the voltammetric response have been studied. The method was extended to determination of methiocarb in spiked soil and river water. Calibration graph is linear between 1.48 ? 55,36 ?g mL?1 (r = 0.9990) in river water and LOD and LOQ were obtain and 0.45 and 1.48 ?g mL?1, respectively The method is successfully applied for the determination of methiocarb in commercial formulation Mesurol® and the average percentage recovery was calculated as % 50,21 ? 3,52 (quoted value is 50%) and the relative standard deviation (RSD) is 0,41% (n=5). Accuracy was in agreement with that obtained by comparison HPLC method.