pH-自动控制系统及其对培养液酸碱度控制

“pH-automatic cotrol system” and its control over the acidity of culture medium

作者设计了能根据培养液pH值变化自动调节通入培养液中的CO_2与O_2混合气中CO_2比例的“医用pH-自动控制仪”(简称pH-控制仪),并将其与酸度计、CO_2、O_2和培养液组合,共同构成“pH自动控制系统”,用于保持实验过程中培养液酸碱度的相对恒定。该系统控制范围为pH6.0～8.5;基本误差≤0.02pH单位;零点漂移≤0.02pH单位/4h;调节过程CO_2流量变化<基础流量±30％。实验也测定了培养液的“温度—pH校正值”。以37℃,pH7.40为校正点,台氏液在30°、25°和20℃的pH校正值分别为7.36、7.31和人29。据此校正值可保证不同温度下控制pH恒定的培养液,皆适于37℃下的实验。最后,作者认为:该方法在控制培养液pH恒定方面,优于目前普遍采用的将含5％CO_2的空气或氧混合气通入培养液的方法。

A pH automatic control system was designed for maintaining pH constant of culture medium in experimental process, and it consists of pH meter, O_2, CO_2 and a 'pH--automatic controller for medicine), which regulates the rate of CO_2 and O_2 in mixture gas automatically according to the pH changes in culture medium. The control range was between 6.0 and 8.5 pH unit, basic deviation was not more than 0.02 pH unit, zero point floatation was equal to or less than 0.02 pH unit/h and CO_2 flow quantity change was less than + /- 30% of the basic CO_2 flow quantity in the regulation. A temperature- pH corrective value was also measured. The pH value of 7.40 at 37℃ was corresponding to that of 7.36, 7.31 and 7.29 at 30℃, 25℃ and 20℃ in Tyrode's selution, respectively. With this corrective value, the culture medium, whose pH had been controlled at a constant level at different temperatures, would be suitable for the experiment performed at 37℃. We tentatively believe that the present pH control system superior to the commomly used methods for pH control with 5% CO_2 mixture gas bubbling in culture medium.