Diuron,as a common used herbicide,is harmful to the environment and human health even in trace or ultra trace for a long term exposure.In this work,trace amount of diuron was detected by differential pulse voltammetry on carbon paste electrode.Thenickel hydroxide was insite deposited electrochemically on carbon paste electrode surface.The herbicide diuron molecule was electromembrance extraction on the surface of the electrode with the help of electrode potential.On the modified electrode,diuron interacts with nickel hydroxide,forms a complex,and makes the nickel first irreversible reduction peak shift to-0.454 V from-0.389 V.The new reduction peak current increases linearly with the increase of scan rate indicating the reduction reaction controlled by surface adsorption.The adsorption process belongs to electromembrane extraction with dependency on the quiet time at fixed initial potential and on the initial potential with normal distributions at fixed quiet time.The extraction behavior follows a Temkin isothermal adsorption model with-22.94 kJ/mol adsorption free energy.The reduction peak current is linear changed with the logarithm of diuron concentration in the range of 0.775 × 103 ～ 0.775 × 10-3 μg/mL,which can be used to determine the concentration of diuron with the limits of detection (S/N =3) of 0.775 × 10-3 μg/mL.The developed electrochemical method for the detection of diuron based on this irreversible reduction peak shows a good reproducibility and selectivity,with satisfactory results for the detection of diuron from agricultural waste water.%敌草隆是一种常用的除草剂,长期以微量甚至痕量暴露于环境中,对环境和人体健康都有害.采用微分脉冲伏安法在碳糊电极上测定了痕量的敌草隆,采用电化学方法在碳糊电极表面原位沉积了氢氧化镍,在电极电位的作用下敌草隆分子被电膜萃取到电极表面.在修饰电极上,敌草隆与氢氧化镍相互作用形成络合物,使镍的第一个不可逆还原峰从-0.389 V移至-0.454 V.新的还原峰电流随扫描速率的增加而线性增加,表明还原反应受表面吸附控制.在固定的初始电位下,吸附过程属于依赖于静止时间的电膜萃取过程.在固定的静止时间下电流随初始电位呈正态分布.萃取过程遵循Temkin等温吸附模型,吸附自由能为-22.94 kJ/mol.还原峰电流与敌草隆浓度的对数在0.775×103～0.775×10-3μg/ml范围内呈线性关系,可以用此方法检测敌草隆,检出限(S/N=3)达到0.775× 10-3μg/mL.基于此不可逆还原峰建立的检测敌草隆的电化学方法,具有良好的重现性和选择性,已用于农业废水中敌草隆的检测,其结果令人满意.
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