Carbon paste electrodes modified with various carbonaceous materials for the determination of 2,4-dichlorophenoxyacetic acid by differential pulse voltammetry

Carbon paste electrodes modified by adding different carbonaceous materials including carbon blacks, carbonized molecular sieves and powdered activated carbons were prepared for detection and determination of 2,4-dichlorophenoxyacetic acid (2,4-D) based on differential pulse voltammetry. The results were obtained using optimized conditions such as 8 min accumulation time and 10% of each modifier content, resulting in a linear relationship of peak current vs. concentration in studied range from 0.01 to 0.5 mmol L-1 for all carbon paste electrodes. Analytical recovery and the precision for prepared electrodes were in the ranges 97.4-106.2% and 1.4-9.5%, respectively. The intensity of the signal increased with the increase in the adsorption ability and the specific surface area of the modifiers. Compared to the unmodified electrode, all the new paste electrodes showed a tens of times greater sensitivity for detection of the herbicide. The proposed methods were also applied to the determination of 2,4-D in real water samples. 2,4-D spiked in river water was determined with good precision and accuracy. (C) 2016 Elsevier B.V. All rights reserved.