Development of the continuous monitoring method of blood ammonia

试图建立一种连续测定血氨浓度的方法。构建了lr-Pd MOS二极管作为氨检测传感器，当氨浓度在0 ~ 15 ppm变化时，其电压线性变化为200 mV。另一个二极管氨传感器（TGS # 814D由费加罗）也进行了测试，显示0-80 ppm之间的线性关系。此外，以聚四氟乙烯为氨透膜的氨气玻璃电极的电极输出线性度范围很广，即0.1 -20 mM。由于该电极系统具有气体和液体均可使用以及外壳易于修改的优点，因此该系统用于进一步分析。将尿素酶固定于直径为50 m的球形纤维素凝胶上，装于70.1的腔室中，采用连续测定氨浓度的系统检测血尿素。通过腔室对血液进行熏香，利用氨气浓度的增加对血液尿素浓度进行检测，该系统在0.1 ~ 100 mM之间电极电势与尿素浓度对数呈极显著相关。该系统成功应用于血液连续监测，患者血液透析期间尿素浓度为肾脏疾病。结果表明，本研究开发的系统可用于肾功能不全患者血液透析的自动控制，也可用于航天器等密闭空间的卫生状况监测。

An attempt was made to develop a method to determine blood ammonia concentration continuously. As the sensor for ammonia detection, lr-Pd MOS diode was constructed, which showed a linear voltage change of 200 mV for 0-15 ppm change in ammonia. An another diode ammonia sensor (TGS # 814D by Figaro) was also tested which showed a lineality between 0-80 ppm. In addition, ammonia gas glass electrode which uses polytetrafluoro-ethylene as an ammonia permeable membrane showed wide range of lineality of electrode output, i.e. 0.1 -20 mM. Because the electrode system has advantages that it is usable for both gas and liquid and that modification of housing is easy, this system was used for further analyses.This system to measure ammonia concentration continuously was applied for the detection of blood urea, for which urease was immobilized to spherical cellulose gel with diameter of 50 m and packed in 70 1 of chamber. Blood was perfumed through the chamber and the increase of ammonia concentration was used for the detection of blood urea concentration, and the system gave highly significant correlation between the emf of the electrode and log of urea concentration between 0.1 and 100 mM. This system was successfully applied for the continuous monitoring of blood, urea concentration during hemodialysis of a patient was kidney disorder.These results suggests that the system developed in this study is applicable for the automated control of hemodialysis of patients with kidney disfunction and also for the monitoring of sanitary condition in confined space such as space craft.