溶液pH对基于金属钼的磷酸根ISE测量性能的影响  

Effect of pH on determination performance of phosphate ISE based on molybdenum

作　　者：刘亚楠 杨慧中 LIU Yanan;YANG Huizhong(Key Laboratory of Advanced Control of Light Industry Process,Ministry of Education,Jiangnan University,Wuxi 214122,China;School of Internet of Things Engineering,Jiangnan University,Wuxi 214122,China)

机构地区：[1]江南大学轻工过程先进控制教育部重点实验室,江苏无锡214122 [2]江南大学物联网工程学院,江苏无锡214122

出　　处：《传感器与微系统》2021年第8期42-45,49,共5页Transducer and Microsystem Technologies

基　　金：国家自然科学基金资助项目(61773181);中央高校基本科研业务费专项资金资助项目(JUSRP51733B)。

摘　　要：金属钼离子选择电极(ISE)在检测磷酸根离子(HPO_(4)^(2-))过程中响应电位容易受到被测溶液pH值的影响,进而影响ISE的测量性能。采用电化学阻抗谱法研究了电极/溶液界面上的电化学过程及被测溶液pH值变化对电极过程动力学参数的影响。利用R(QR)或R(Q(RZ_(w)))等效电路拟合电极/溶液界面的双电层结构,可以发现,当被测溶液pH=11时,钼电极的电荷转移电阻R_(ct)达到最低,此时电极表面反应程度最高,有利于提高钼电极对磷酸根离子的检测性能。通过检测一系列已知浓度的Na_(2)HPO_(4)溶液响应电位,评估了钼电极的检测性能,结果表明:在pH值为11的10^(-6)~10^(-1)mol/L的Na_(2)HPO_(4)标准溶液中,钼电极的检测斜率可达到-28.29 mV/(°),接近能斯特响应斜率,具有较好的检测性能。The response potential of ion selective electrode(ISE)based on metal molybdenum is easily affected by the pH value of the measured solution in the process of detecting phosphate ion(HPO_(4)^(2-)),which further affects the measurement performance of the molybdenum electrode.The electrochemical process of the electrode/solution interface and the influence of the pH value of the measured solution on the kinetic parameters of the electrode are studied by electrochemical impedance spectroscopy.When R(QR)or R(Q(RZ_(w)))equivalent circuits are used to fit the double-layer structure of the electrode/solution interface,it can be found when the pH value of the solution being tested is 11,the charge transfer resistance R ct of the molybdenum electrode is the lowest,and the surface of the electrode is most reactive at this time,which is beneficial to improve the detection performance of the phosphate ion by the molybdenum electrode.The detection performance of the molybdenum electrode is evaluated by measuring a series of known concentrations of Na_(2)HPO_(4)solution.The experimental results show that the detection slope of the molybdenum electrode reaches-28.29 mV/(°)in the 10^(-6)~10^(-1)mol/L Na_(2)HPO_(4)standard solution with pH equal to 11,which is close to the Nernst response slope,and has a good detection performance.

关 键 词：离子选择电极 钼电极 电化学阻抗谱 磷酸根 

分 类 号：TP212[自动化与计算机技术—检测技术与自动化装置] TQ150.1[自动化与计算机技术—控制科学与工程]