Electrochemical determination of diuron using platinum nanoparticle and molecularly imprinted technology

Diuron is a herbicide belonging to the urea family which is widely used to eliminate weeds at uncultivated levels and in products such as citrus, rice, cotton, soy, sugarcane, potato, wheat, coffee [1] and, moreover, in runways, railways and pipelines. Because of its stability and shelf-life in water and soil, diuron lead to environmental impacts on plants and mammals. In plants, it is absorbed through the root, then stems and breaks, and eventually prevents photosynthesis. In addition, in humans, it can be led to formation of Methemoglobin in the blood, liver, and spleen abnormalities and disturbs the processes of the natural release and transfer of hormones in the body [2]. Molecular imprinting is a process where a layer is synthesized in the presence of a molecular template, a process that generates cavities within network that are complementary to the template molecule in size, shape, and position of functional groups [3]. In this work, a sensitive electrochemical sensor based on imprinted technology was applied to determine diuron. Cyclic voltammetry and differential pulse voltammetry were applied to investigate the electrochemical response of the diuron on the electrode surface. To prepare the modified pencil graphite electrode (PGE), initially, a mixture of chitosan and carbon nanotubes is placed on the PGE surfac. Then, the electrode was applied as the working electrode in the electrochemical cell containing 60 mM KNO3, 2.4 mM 3-methyl-4-nitrophenol, 0.5 mM diuron, 0.26 mM Pt(IV), and 2.7 M H2SO4 and a layer was formed on the electrode surface. After that, the modified PGE was placed into the methanol (60% v/v) solution to remove diuron and form imprinted layer. Finally the imprinted PGE was placed into the diuron solutions with different concentrations and the peak current at 0.6 V was measured. Diuron was determined in water samples using constructed sensor.