Nitrite ions can penetrate from fertilizers into underground water and consequently contaminate thewater and food sources. A facile two-step electrochemical method was used to fabricategold/polyaniline/carbon paste electrode (Au/PAni/CPE) for nitrite sensing. The Au/PAni/CPE wasvisualized and characterized by scanning electron microscopy, energy-dispersed X-ray spectroscopy,X-ray diffraction and electrochemical methods. The electrocatalytic activity of bare CPE, PAni/CPEand Au/PAni/CPE toward the electrooxidation of nitrite was examined and compared via cyclicvoltammetry. To obtain the optimal condition for fabrication of the electrode, the number of cycles incyclic voltammetry for synthesis of polyaniline and the deposition time in potentiostatic deposition ofgold were optimized with respect to the electrooxidation of nitrite. In a phosphate buffer solution (PBS, pH 7.0), the peak current was linear to the concentration of nitrite in the range from 3.810 M to 1.010 M with a detection limit of 2.510 M. The interference effect on the nitrite detection wasalso studied. The proposed method was also employed for the determination of nitrite in rain and lakewater samples.
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机译：亚硝酸根离子可从肥料渗透到地下水中，从而污染水和食物来源。一种简便的两步电化学方法被用于制造用于亚硝酸盐感测的金/聚苯胺/碳糊电极（Au / PAni / CPE）。通过扫描电子显微镜，能量分散X射线光谱，X射线衍射和电化学方法对Au / PAni / CPE进行了可视化和表征。通过循环伏安法检测并比较了裸露的CPE，PAni / CPE和Au / PAni / CPE对亚硝酸盐的电氧化的电催化活性。为了获得最佳的电极制造条件，针对亚硝酸盐的电氧化，优化了用于合成聚苯胺的循环伏安法的循环次数和金的恒电位沉积中的沉积时间。在磷酸盐缓冲溶液（PBS，pH 7.0）中，峰值电流与亚硝酸盐浓度在3.810 M至1.010 M范围内线性相关，检出限为2.510M。还研究了对亚硝酸盐检测的干扰作用。该方法还用于测定雨水和湖水样品中的亚硝酸盐。
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