Modification of Carbon Paste Electrode Based on Molecularly Imprinted Polymer for Electrochemical Determination of Diazinon in Biological and Environmental Samples

The wide use of pesticides can lead to environmental and human adverse effects. Diazinon, as an organophosphorous pesticide, is used in agriculture because of its low cost and high efficiency on insects. Due to the increasing application of pesticides, accurate analytical methods are necessary. The aim of this work was modification of carbon paste electrode composition and applying it as a sensor for determination of diazinon in biological and environmental samples. Multi-walls carbon nanotubes and a molecularly imprinted polymer were used as modifiers in the sensor composition. A molecularly imprinted polymer and a non-imprinted polymer were synthesized for applying in the electrode. After optimization of electrode composition, it was used to determine the analyte concentration. Instrumental parameters affecting the square wave voltammetric response were adjusted to obtain the highest current intensity. The modified electrode with MIP showed very high recognition ability compared to the electrode containing NIP. The obtained linear range was 5x10(-10) to 1x10(-6)molL(-1). The detection limit of the sensor was 1.3x10(-10)molL(-1) and the relative standard deviation for analysis of target molecule by the proposed sensor was 2.87%. This sensor was used to determine the diazinon in real samples (human urine, tap, and river water samples) without special sample preparation before analysis. The optimization of electrode composition containing mentioned modifiers improved its response considerably.