医用微型玻璃电极的结构与特性

STRUCTURE AND PROPERTIES OF MEDICAL MICRO GLASS ELECTRODES

医用微型玻璃电极采用固体可逆接触式结构 ,直径 2mm ,长约 7～ 8mm。电极用于测定人体胃液pH值与电位差 ,可诊断胃病与早期发现胃癌。研究了微型玻璃电极敏感玻璃膜的成分与性质 ,在Li2 OLa2 O3SiO2 系统中加入摩尔分数为 2 %的Ta2 O5可提高敏感玻璃的耐水性与电导率。电极在 pH值为 1～ 9范围内具有良好的Nernst响应性 ,而且重现性和稳定性均比较好。电极的酸误差较小 ,电势随时间的漂移率约为 1.5mV/h。对 2 5只大白鼠胃液的 pH值和电位差进行测定 ,测得大白鼠胃液的pH值范围为 2～ 5。与PB 2 0型SartoriusAG酸度计所测的pH值相比较 ,得知此种电极的平均偏差较小 ,约为± 0 .2。人体正常胃液酸度范围的pH值为 2～ 3 ,由此判断电极用于人体胃液的测定是可能的。

The structure of medical micro glass electrodes is reversible solid contact with the diameter of 2 mm and length of 7-8 mm. Such electrodes are used for determining the pH value and potential difference in mortal stomach juice, so that gastropathy and stomach pre-cancer can be early detected. The composition and properties of the sensitive glass film for the electrodes are studied. The water resistance and conductivity would be improved by adding 2% (in mole) Ta_2O_5 to the glass system Li_2OLa_2O_3SiO_2. A better Nernst response , stability, and reproducibility of the glass electrodes exist in the range of pH=1-9. There is a little acid error in this kind of electrode and the drift mobility of the potential difference with time is about (1.5 mV/h). The pH value and potential difference surveyed for stomach juice of 25 pieces of white rats by such electrodes is within 2-5. As compared with the measurement of pH values by PB20 Sartorius AG acidimeter, the statistical figures show that the average deviation of such electrodes is slight, approximate±0.2. The pH range of mortal stomach juice is pH=2-3 at normal status. It can be concluded from this result that it is possible to utilize for the detection of mortal stomach juice by this kind of electrodes.