Development of chemical sensors for concentrated solutions

该项目的目的是开发用于酸、碱和氧化还原化合物浓缩液的化学传感器。该传感器由内电极和由聚电解质制备的内填充缓冲液组成，内填充缓冲液由透析膜覆盖。主要研究成果如下：(1)氧化还原化合物的电位型传感器研制了过氧化氢和抗坏血酸的电位型传感器。该传感器以铂电极和银氯化银参比电极为内电极，以聚苯乙烯磺酸制备的Fe(II)和Fe(III)形式的电位缓冲溶液为内填充溶液。传感器的末端覆盖有透析膜(维京膜)。内充液的体积小于30微升，可通过注射器泵进行更换。当传感器浸入过氧化氢溶液中时，过氧化氢、过氧化氢扩散…更多的渗入穿过透析膜的内填充溶液。在30min后，由于过氧化氢将Fe(II)氧化成Fe(III)，随着过氧化氢扩散浓度的增加，内铂电极的电位发生变化。在0.1M~1M范围内，电位与过氧化氢的浓度呈线性关系。(2)浓酸和强碱的电位型pH传感器研制了与上述氧化还原化合物pH传感器类似的传感器。内填充液为聚丙烯酸和聚丙烯酸钠盐配制的pH缓冲液。内电极采用锑电极。将所研制的pH传感器浸入2M~8M的盐酸溶液中，考察了传感器的响应情况。在样品溶液中浸泡3~5min后，随着时间的延长，传感器的电位变化增大。在2~8M范围内，电势随时间的变化与HCl浓度呈线性关系。透析膜的有效面积和厚度是控制内充液中HCl扩散量的重要因素。以聚乙烯亚胺及其盐酸盐为内填充液，研制了浓氢氧化钠pH传感器。较少

The purpose of this project is to develop chemical sensors for concentrated solution of acids, bases and redox compounds. The sensor consists of an inner electrode and an inner filling buffer solution prepared by polyelectrolyte, which are covered with a dialysis membrane. Followings are the summary of the results obtained by this project.(1)Potentiometric sensors for redox compoundsThe potentiometric sensors for hydrogen peroxide and ascorbic acid were developed. The sensors consist of a platinum electrode and a silver-silver chloride reference electrode as the inner electrodes and a potential buffer solution prepared by polystyrene sulfonic acid in Fe(II) and Fe(III) form as the inner filling solution. The end of the sensors was covered with a dialysis membrane (Viking membrane). The volume of the inner filling solution was less than 30 muL, which is capable to change by syringe pump. When the sensor was immersed into the hydrogen peroxide solution, hydrogen, hydrogen peroxide diffus … More ed into the inner filling solution across the dialysis membrane. The potential of the inner platinum electrode is changed as increasing concentration of hydrogen peroxide diffused due to oxidation of Fe(II) to Fe(III) with hydrogen peroxide after 30 min time lag. The potential change with time was found to be linear to the concentration of hydrogen peroxide in the range from 0.1 M to 1 M.Ascorbic acid was also successfully determined by the developed sensor.(2)Potentiometric pH sensor for concentrated acids and basesThe similar pH sensor to the above sensor for redox compounds was developed. The inner filling solution is a pH buffer solution prepared by polyacrylic acid and polyacrylic acid sodium salt. An antimony electrode was uses as the inner electrode. The response of the developed pH sensor was examined by immersing the sensor into HCl solution of 2 M to 8 M.The potential change was observed to increase with increasing time after 3-5 min time lag when the sensor was immersed into the sample solution. The potential change with time was found to be linear to the concentration of HCl from 2 M to 8 M.The effective area and thickness of the dialysis membrane were found to be important factor to control the amount of HCl diffused in the inner filling solution. The pH sensor for concentrated sodium hydrooxide was also developed by using polyethyleneimin and its hydrochloride as the inner filling solution. Less