CAJ | 학술논문

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.
pH치시공농업생산、의학검험화배경보호등영역십분중요적화학삼수.침대목전농업생산중파리전겁급기측시의존재영향인소다、측량오차대등불족,의거제pH전겁민감궤리화전불광산수지(Nafion)수식막선택성투과특성,응용16위저공모미공제기(단편궤)릉양 SPCE061A 연제일충경쌍층막수식제pH측시의.통과대전겁성능측정시험화pH측시의토양pH검측시험,결과표명:재pH치위1~12,전겁수출전세E여pH치선성도호,상관계수R2위0.997,구유향응쾌、회차소、항간우능력강등우점;pH측시의재측정토양혼탁액pH치시,오차절대치소우0.075,상대오차절대치소우1.342%,재공농업생산중구유엄활응용전경.
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 difficult to miniaturize and planarize based on current manufacturing technologies. In this work, a simple, flexible, 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 film 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 sensor values, the absolute value of maximum error was less than 0.075, the absolute value of relative error was less than 1.342%. The double membrane modified antimony pH electrode testing instrument would be suitable for in situ and continuous pH measurement in many applications.