Issues to pay attention to when using pH meters
Before performing the operation, the integrity of the electrodes should be checked first. At present, most of the electrodes used in pH meters are composite electrodes, while the older generation pH meters still use glass electrodes and calomel electrodes. Due to the widespread use of composite electrodes, the following mainly discusses composite electrodes.
Calibrate the instrument according to its instructions and adjust the test solution and standard buffer solution to the same temperature. First, insert the electrode into a standard buffer solution with a pH difference of no more than two pH units from the tested sample. Turn on the reading switch, adjust the locator to make the reading exactly the pH of the standard solution, and repeat several times to stabilize the reading. After removing the electrode and washing it, insert it into the first standard buffer solution. Once the instrument is accurate and accurate, it can be used to determine the sample.
The main steps of using an acidity meter are:
1. Turn on the power switch for preheating.
2. Perform temperature compensation.
3. Use standard solution for positioning.
4. Use standard solution for slope correction.
5. Measure pH.
Notes:
1. The newly used glass electrode should be soaked in distilled water for activation for 48 hours before use.
2. The wall of the bulb area of the glass electrode is very thin, and double protection should be provided when using it.
3. The test solution should be at the same temperature as the standard buffer solution, otherwise temperature compensation and adjustment need to be carried out again.
When replacing the test solution, the electrode must be washed and wiped dry.
There are mainly two types of composite electrodes used in laboratories: fully enclosed and non enclosed. The fully enclosed type is relatively rare and mainly produced by foreign enterprises. Before using the composite electrode, first check whether the glass bulb has cracks or breakage. If not, use a pH buffer solution for two-point calibration. When the positioning and slope buttons can be adjusted to the corresponding pH value, it is generally considered usable. Otherwise, electrode activation treatment can be carried out according to the user manual.
