Determination method of phosphate ion based on molybdenum ion selective electrode
LIU Yanan1,, YANG Huizhong1,2,,, CUI Baotong2 1.Key Laboratory of Advanced Control of Light Industry Process, Ministry of Education, Jiangnan University, Wuxi 214122, China 2.School of Internet of Things Engineering, Jiangnan University, Wuxi 214122, China
Abstract:In the process of phosphate ion detection based on metal molybdenum ion-selective electrode, the changes of pH and temperature of the measured solution are important factors affecting the electrode detection accuracy. The relationships between the output potential of the molybdenum electrode and the phosphate ion concentration, pH value and temperature of the tested solution were studied, and the influence of various interference factors on the detection results were discussed. Based on the distribution coefficient of phosphate at different pHs and Nernst equation, a mathematical model was established with the least squares regression analysis method between the output potential of the molybdenum electrode and the phosphate ion concentration, pH and temperature. The experimental results show that the relative error of the measurement model in Na2HPO4 solution of 10?6~10?1 mol·L?1 was within 6.33%. And compared with the ion chromatography detection, the maximum relative error was 5.50%. Therefore, the electrode method combined with the multiple linear regression model for the detection of the content of phosphate ion in the environmental water can compensate the influence of the pH and temperature changes of the measured solution on the electrode measurement. This method can effectively improve the measurement accuracy of phosphate ion selective electrode. Key words:ion selective electrode/ phosphate/ compensation model/ distribution coefficient/ temperature.
图1磷酸根离子分布系数 Figure1.Phosphate ion distribution coefficient
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1.Key Laboratory of Advanced Control of Light Industry Process, Ministry of Education, Jiangnan University, Wuxi 214122, China 2.School of Internet of Things Engineering, Jiangnan University, Wuxi 214122, China Received Date: 2020-01-15 Accepted Date: 2020-05-10 Available Online: 2020-12-08 Keywords:ion selective electrode/ phosphate/ compensation model/ distribution coefficient/ temperature Abstract:In the process of phosphate ion detection based on metal molybdenum ion-selective electrode, the changes of pH and temperature of the measured solution are important factors affecting the electrode detection accuracy. The relationships between the output potential of the molybdenum electrode and the phosphate ion concentration, pH value and temperature of the tested solution were studied, and the influence of various interference factors on the detection results were discussed. Based on the distribution coefficient of phosphate at different pHs and Nernst equation, a mathematical model was established with the least squares regression analysis method between the output potential of the molybdenum electrode and the phosphate ion concentration, pH and temperature. The experimental results show that the relative error of the measurement model in Na2HPO4 solution of 10?6~10?1 mol·L?1 was within 6.33%. And compared with the ion chromatography detection, the maximum relative error was 5.50%. Therefore, the electrode method combined with the multiple linear regression model for the detection of the content of phosphate ion in the environmental water can compensate the influence of the pH and temperature changes of the measured solution on the electrode measurement. This method can effectively improve the measurement accuracy of phosphate ion selective electrode.
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