双层膜锑pH电极及其测试仪的研制与应用  

Development and application of double membrane modified antimony pH electrode and its testing instrument

作　　者：盛庆元[1] 张西良[2] 李萍萍[3] 刘丽晨[2] 陈书田[2] 

机构地区：[1]江苏大学农业工程研究院现代农业装备与技术省部共建教育部重点实验室/江苏省重点实验室,镇江212013 [2]江苏大学机械工程学院,镇江212013 [3]南京林业大学森林资源与环境学院,南京210037

出　　处：《农业工程学报》2013年第6期59-65,共7页Transactions of the Chinese Society of Agricultural Engineering

基　　金：十二五国家支撑计划(2011BAD12B01-02);国家星火计划项目(2010GA690001);国家公益性行业(农业)科研专项(201203095);江苏省科技支撑计划(BE2010347);江苏大学大学生科研项目(11B019)

摘　　要：pH值是工农业生产、医学检验和环境保护等领域十分重要的化学参数。针对目前农业生产中玻璃电极及其测试仪存在影响因素多、测量误差大等不足,依据锑pH电极敏感机理和全氟磺酸树脂(Nafion)修饰膜选择性透过特性,应用16位低功耗微控制器(单片机)凌阳SPCE061A研制一种经双层膜修饰锑pH测试仪。通过对电极性能测定试验和pH测试仪土壤pH检测试验,结果表明:在pH值为1～12,电极输出电势E与pH值线性度好,相关系数R2为0.997,具有响应快、回差小、抗干扰能力强等优点;pH测试仪在测定土壤浑浊液pH值时,误差绝对值小于0.075,相对误差绝对值小于1.342%,在工农业生产中具有广阔应用前景。The value of pH is a key chemical parameter in the field of industrial and agricultural production, medicine, environmental protection and other fields. At present, commercial glass pH electrodes have been widely used in soil pH test in the laboratory due to its convenience and reliability. But with turbid and vibrate systems in the filed like on-the-go pH mapping, glass electrode cannot be used because of its brittleness of the glass membrane, sluggish response, which are dif？cult to miniaturize and planarize based on current manufacturing technologies. In this work, a simple, ？exible, inexpensive and effective way to make bilayer membrane modified antimony pH electrode was presented and one pH tester was developed. The surface of the obtained antimony wire was oxidized in sodium dioxide melt to fabricate an antimony oxide ？lm for pH sensing as first layer. The second layer was Nafion membrane with selective characteristics, which was coated after the first layer. The sensing response and open-circuit potential of the electrode had a good linear relationship （R2 =0.997） with pH value in the test solution, which also exhibited small hysteresis, fast response than that of bare antimony pH electrode. The open-circuit potential of the electrode was almost drift-free, with an average variation as small as 0.1mV over an hour. Ion interference experiment showed that this electrode has good selectivity with common ions （Na＋, K＋, Ca2＋, Cl-, Br- ） in soil, redox ion（[Fe（CN）6]3-, [Fe（CN）6]4-） and citrate ions （ C6H5O73- ）. The bilayer membrane modified antimony pH electrode and the Ag/AgCl reference electrode as sensor were employed to pH tester, which was designed based on 16 bit low power consumption microcontroller （Sunplus SPCE061A）. Tester readings in soil turbid solution under controlled in the lab were compared with the data obtained by standard protocols of soil. The tests demonstrated a high degree of linearity between standard laboratory values and turbid soil solution sens

关 键 词：电极 单片机 农业机械 NAFION膜 PH值 测试仪 

分 类 号：TP212.2[自动化与计算机技术—检测技术与自动化装置]