集成Ti/TiO_(2)敏感电极和液接式Ag/AgCl参比电极的pH微纳传感器

pH Micro-Nano Sensor Integrating Ti/TiO_(2) Sensitive Electrode and Liquid-Junction Ag/AgCl Reference Electrode

常见的pH传感器大多采用电位法进行检测,基于电位法进行检测的传感器由敏感电极和参比电极组成。在尺寸仅为5 mm×5 mm的传感器芯片上制备了钛电极、银电极和铂电阻丝。采用电化学氧化的方法对钛电极进行阳极氧化制成Ti/TiO_(2)敏感电极。采用电化学氯化的方法对银电极进行阳极氯化,再将饱和KCl溶液(3 mol/L)注入参比槽制成Ag/AgCl参比电极。铂电阻丝作为测温元件用于对pH值进行校准,电阻灵敏度约为14.21Ω/℃。在室温下、溶液温度为(13±1)℃时,测试芯片在不同pH值(4~10)溶液中的电压。通过线性分析得到传感器的分辨率约为17.92 mV/pH。控制溶液温度不变,对芯片在不同pH值(4.00、6.00、8.00和10.00)溶液中的电压进行测试,并得到该温度下的传感器分辨率。在不同溶液温度下对传感器的分辨率进行测试。测得不同溶液温度(25、20、15和10℃)下传感器的分辨率分别为28.31、23.45、19.33和13.62 mV/pH。通过温度补偿公式对pH值进行校准,计算得到的理论pH值与实际测量值的偏差≤0.25。传感器芯片具有体积小且易于集成的特点,可应用于各种水环境的检测。

Most common pH sensors are tested by the potentiometric method,and the sensor based on the potentiometric method is composed of a sensitive electrode and a reference electrode.The titanium electrode,silver electrode and platinum resistance wire were prepared on a sensor chip with the size of only 5 mm×5 mm.By using electrochemical oxidation method,the anodic oxidation of the titanium electrode was carried out to prepare Ti/TiO_(2) sensitive electrode.The anodic chlorination of the silver electrode was carried out by electrochemical chlorination method.And then the saturated KCl solution(3 mol/L)was injected into the reference cell to prepare the Ag/AgCl reference electrode.The platinum resistance wire was used as measure temperature element for pH vaule calibration,and the resistance sensitivity was about 14.21Ω/℃.When the solution temperature was(13±1)℃,the voltage of the chip was tested in solutions with different pH vaules(4-10)at room temperature.Through linear analysis,the resolution of the sensor is about 17.92 mV/pH.At constant solution temperature,the voltages of the chip in solutions with different pH values(4.00,6.00,8.00 and 10.00)were measured,and the sensor resolution was obtained at the corresponding temperature.The resolution of the sensor was tested at different solution temperatures.The result shows that at 25,20,15 and 10℃solution temperatures,the resolutions of the sensor are 28.31,23.45,19.33 and 13.62 mV/pH,respectively.The pH vaule was calibrated through the temperature compensation formula.The calculated deviation between the theoretical pH value and the actual measured value is≤0.25.The sensor chip has the characteristics of small size and easy integration,and can be applied to the detection of various water environments.