| 摘要 |
PURPOSE:To easily detect the abnormality of a potential measuring system by measuring the potential difference between a pair of ion selective electrodes when a reference liquid and liquid to be inspected are supplied to an ion activity measuring system and further measuring the potential difference when a resistor of a prescribed value is connected in parallel to a potentiometer. CONSTITUTION:The potential difference E between a pair of ion selective electrodes is measured by a potentiometric system V when the reference liquid and the liquid to be inspected are supplied to the ion activity measuring system A by turning a switch SW off. The potential difference ER when the resistor Re having the value of 0.1-10 times the value of the internal resistance of the ion selective electrode pair is connected in parallel to the potentiometer V by turning the switch SW on is measured. Discrimination is made that the internal impedance Ri of the measuring system A is abnormal if such potential difference is out of a permissible range as compared to the standard relation between E and ER preliminarily determined from the standard value of Ri. |
