Electrochemical detection of Diazinon using carbon nanotubes carbon paste electrode as a Sensor

Due to the large amounts of pesticides commonly used and their impact on health, rapid and accurate pesticide analysis is important. In order to achieve high productivity, the use of pesticide has increased up to many folds. These pesticides contain organophosphorus (OP) toxic compounds which interfere with the proper functioning of enzyme acetylcholinesterase (AChE) and finally affect the central nervous system. Diazinon (DZN) is an anti-cholinesterase compound that inhibits cholinesterase, an enzyme indispensable for the function of central nervous system. So, there is a need for routine, continuous, low cost detection of OP compounds which are the main limitations associated with conventional analytical methods. Due to the mentioned harmful effects, it is necessary to develop the methods which are fast, sensitive, and reliable for the detection of OP pesticides in fruits, vegetables and water. Electrochemical analysis based on chemically modified electrodes has proved a sensitive and selective method for the determination of Ops. The electrochemical detection can be accomplished rapidly without tedious separation and might be suitable for continuous monitoring and in situ detection. The carbon nanotubes (CNTs) shows that they have capability to improve electron transfer reactions and have a great electro catalytic efficacy as electrode materials, according to these fascinating properties, CNTs are best candidates for modifying electrodes. A sensitive and selective electrochemical sensor was successfully developed on carbon nanotubes modified carbon paste electrode(CPE) and used to detect the Diazinon in acetate buffer solution and stock solution of DZN (0.01M) in ethanol was prepared. The electrochemical behavior of CNT/CPE was studied by cyclic voltammetry (CV) and Differential pulse voltammetry (DPV) at the working electrode. The structure and electrochemical properties of CNTCPE was investigated in potassium ferricyanide 1mM solution. The influence of scan rate on the peak current of DZN on CNT/CPE was studied in the range of 5 to 140 mv/s. In optimal working conditions, the peak current of DZN at this modified electrode exhibited a good linear relationship (R2 =0.9801) with DZN concentration in the range of 1×10-10 to 6×10-8 M. In this paper, determination of DZN using CNT/CPE is explained. CNT display high electro catalytic activity to DZN which provides sensitivity and selectivity of the modified carbon paste electrode. The fabricated electrochemical sensor displayed a linear and sensitive response to DZN. The obtained linear range was within the concentration range of 1×1010 to 6×10-8 M. The detection limit was found to be 4.5×10-10. So this fabricated electrochemical sensor was successfully used for determination of DZN

کلیدواژه ها:

carbon nanotubes ، carbon paste electrode ، Diazinon ، electrochemical sensor organophosphate