What should you pay attention to when measuring with the acidometer sensor?
Before proceeding, the integrity of the electrodes should be checked first. At present, most of the electrodes used on acidimeters (pH meters) are composite electrodes. The older generation of acidimeters still use glass electrodes and calomel electrodes. Since composite electrodes are widely used, the following mainly discusses composite electrodes.
Currently, the composite electrodes used in laboratories mainly include fully enclosed and non-enclosed types. There are relatively few fully enclosed electrodes, which are mainly produced by foreign companies. Before using the composite electrode, first check whether the glass bulb is cracked or broken. If not, when performing two-point calibration with a pH buffer solution, when both the positioning and slope buttons can be adjusted to the corresponding pH value, it is generally considered safe to use. Otherwise, press Use the instructions for electrode activation. The activation method is to soak it in 4% hydrogen fluoride solution for about 3 to 5 seconds, take it out and rinse it with distilled water, then soak it in 0.1mol/L hydrochloric acid solution for several hours, rinse it with distilled water, and then calibrate it, that is, use the pH value Position the buffer solution at 6.86 (25°C). After adjustment, select another pH buffer solution to adjust the slope. If it cannot be adjusted, the electrode needs to be replaced. For non-sealed composite electrodes, an external reference solution, that is, 3 mol/L potassium chloride solution, must be added. Therefore, it is necessary to check whether the potassium chloride solution in the electrode is above 1/3. If it is not, 3 mol/L needs to be added. Potassium chloride solution. If the potassium chloride solution exceeds the position of the small hole, shake off the excess potassium chloride solution so that the solution is under the small hole, and check whether there are bubbles in the solution. If there are bubbles, flick the electrode to drive them out completely.
