How to replace the battery of a pen-type pH meter:
The pen type pH meter has a black board with a switch on it. Gently pull it out without breaking the wires, and you can see four 1.5V batteries. Simply pull out and replace them;
Pay attention to the polarity of the pen type pH meter battery and choose the same model of battery;
When inserting the pH electrode into the test solution or calibration buffer, it should not exceed the maximum height indicated on the test pen.
If the pH electrode is left for a long time and the sensitive bulb is exposed to air, the response will slow down and the displayed value will be unstable due to the dryness of the electrode At this point, the electrode should be immersed in distilled water to activate for a few hours;
To improve performance, insert the pH meter electrode into distilled water at least once a week for a few minutes each time;
Protein precipitates (such as milk or cheese) should be immersed in a solution of gastric protease and hydrochloric acid for elimination treatment; This solution should be prepared before use. After use, immerse the electrode in this solution for a few hours, then rinse with clean water, and finally immerse it in distilled water for a few hours;
The oil film also affects the measurement of sensitive bubbles. Li removed this film, washed the sensitive bubbles with a 75% alcohol solution, wiped them dry with filter paper, rinsed them with water, and then immersed them in distilled water for several hours;
PH calibration of pen type pH meter
Immerse the pen type pH meter electrode into a mixed phosphate standard buffer solution with a pH value of 6.86 (at 25 ℃) and gently shake it;
Adjust the calibration potentiometer with a small screwdriver until the displayed value matches the pH value of the standard buffer solution at ambient temperature;
Insert the pH electrode into a standard buffer solution of potassium hydrogen phthalate at pH 4.01 or borax at pH 9.18;
The displayed value should be within the allowable range of error compared to the pH value of the buffer solution.
