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通过浸涂法在钨金属丝上涂敷氧化钨氢离子敏感膜,制备了氧化钨H+选择性电极,采用尿素改性聚乙烯醇作为参比电极的固态薄膜材料并进行KCl掺杂,经Nafion膜进行修饰后制备了固态参比电极.利用自制的氧化钨pH电极与固态参比电极制成pH电化学传感器,该传感器具有良好的响应电位E-pH线性函数关系,响应范围为pH2~pH11.响应灵敏度与氧化钨的热处理温度有关,200℃热处理后的响应灵敏度为52.81 mV/pH,响应时间与氧化钨敏感膜、测试溶液pH值以及溶液温度有关.在pH2→pH11→pH2循环测试过程中,传感器的滞后效应较小.该传感器有良好的选择性,响应行为不受Na+、F-等常见离子的影响,但是受到氧化还原性的NO-3、I-等离子的干扰.传感器内阻很低为22.8 kΩ,远小于玻璃pH计的内阻(1×109Ω).该传感器在各种饮料中具有较高测量精度,与玻璃pH计的测量值进行对比,两者的差值在(-0.06 pH,+0.15pH)范围内.在10-5M→10-1M柠檬酸溶液中,传感器的响应电位与溶液浓度存在良好的线性关系,响应时间小于1 min.
A tungsten oxide hydrogen ion sensitive film was coated on a tungsten wire by a dip coating method to prepare a tungsten oxide H + selective electrode. Urea-modified polyvinyl alcohol was used as a reference electrode solid film material and doped with KCl. After Nafion The solid-state reference electrode was prepared by modification of membrane.The pH electrochemical sensor was fabricated by self-made tungsten oxide pH electrode and solid-state reference electrode.The sensor has a good response potential E-pH linear function, the response range is pH2 ~ pH11 The response sensitivity is related to the heat treatment temperature of tungsten oxide, and the response sensitivity after heat treatment at 200 ℃ is 52.81 mV / pH.The response time is related to the Tungsten oxide sensitive membrane, the pH value of the test solution and the temperature of the solution.In the cycle of pH2 → pH11 → pH2 , The sensor has a small hysteresis effect.The sensor has good selectivity, the response behavior is not affected by Na +, F- and other common ions, but by the redox NO-3, I-plasma interference sensor internal resistance Very low, 22.8 kΩ, far less than the internal resistance of the glass pH meter (1 × 109Ω). The sensor has a higher measurement accuracy in a wide variety of beverages, compared with the glass pH meter, with a difference between -0.06 pH, + 0.15pH). In 10-5M → 10-1M citric acid solution, there was a good linear relationship between the response potential of the sensor and the solution concentration, and the response time was less than 1 min.