Maintenance and use of pH meter

The use of acidity meter pH meter referred to as the pH meter consists of two parts: the electrode and the electricity meter. If the electrode can be properly maintained during use, the standard buffer can be prepared as required, and the correct operation of the electricity meter, the pH indication error can be greatly reduced, thereby improving the feasibility of the chemical experiment and medical test data.

First, the correct use and maintenance of electrodes The electrodes used in the laboratory are composite electrodes, its advantages are easy to use, without the impact of oxidizing or reducing substances, and the balance of faster. In use, the rubber sleeve and the rubber sleeve at the bottom of the electrode filling port are completely removed to maintain the hydraulic pressure difference of the potassium chloride solution in the electrode. Here's a simple introduction to the use and maintenance of the electrode:

1. When the composite electrode is not used, it can be fully immersed in 3M potassium chloride solution. Never wash with wash solution or other absorbent agents.

2. Before use, check the bulb at the front of the glass electrode. Under normal conditions, the electrode should be transparent and free from cracks; the bulb should be filled with a solution and no bubbles should be present.

3. When measuring a solution with a large concentration, try to shorten the measurement time as much as possible and carefully clean it after use to prevent the measured liquid from adhering to the electrode and contaminating the electrode.

4. After cleaning the electrode, do not wipe the glass film with filter paper, and use filter paper to dry it to avoid damage to the glass film and to prevent cross contamination. This will affect the measurement accuracy.

5. The silver-silver chloride internal reference electrode of the measurement electrode should be immersed in the chloride buffer solution in the bulb to avoid the phenomenon of digital chattering in the display part of the electricity meter. When using, pay attention to gently swing the electrode.

6. The electrode cannot be used for strong acids, alkalis or other corrosive solutions.

7. It is strictly prohibited to use in dehydrating medium such as absolute ethanol, potassium dichromate, etc.

Second, the preparation and storage of standard buffer 1. The pH reference material should be stored in a dry place, such as mixed phosphate pH standard substance will occur when the humidity is high, deliquescence, once the deliquescence, the pH reference material can not be used.

2. The preparation of pH standard solution should use double distilled or deionized water. If you are using a 0.1 pH meter, use distilled water.

3. The pH standard solution should be diluted with a smaller beaker to reduce the pH standard solution on the beaker wall. Plastic bags or other containers for storage of the pH standard substance should be rinsed with distilled water several times in addition to the plastic bags or other containers, and then poured into the formulated pH standard solution to ensure that the prepared pH standard solution is accurate.

4. The prepared standard buffer solution can generally be preserved for 2-3 months. If turbidity, mildew or sedimentation is found, it cannot be used.

5. Alkaline standard solution should be sealed in a polyethylene bottle. Prevent carbon dioxide from entering the standard solution to form carbonic acid and reduce its pH.