A portable pH meter or acidity meter is an instrument used to measure the pH value of a solution, widely used in laboratories, agriculture, water quality monitoring, and other fields. The following is the usage method of a portable pH meter, including preparation, measurement, and maintenance steps.
1. Preparation work
a. Check the instrument
Ensure that the pH meter is in good working condition and check if the battery is charged.
Check if the electrodes are clean and intact, ensuring no cracks or contamination.
b. Calibration
Choose standard buffer: Calibration is usually performed using standard buffer solutions with pH 4.00, 7.00, and 10.00.
Calibration steps:
Turn on the pH meter, place the electrode in a standard buffer solution with pH 7.00, wait for the display to stabilize, and then press the "Calibrate" or "SET" button.
Repeat the above steps and calibrate with buffer solutions at pH 4.00 and pH 10.00. If only single point calibration is required, one of the buffer solutions can be selected for calibration.
Record the pH value of each calibration for future reference.
2. Measurement steps
a. Preparation before measurement
Clean the electrode: Clean the electrode with deionized water or distilled water and gently pat dry.
Adapt the electrode: If the electrode has just been removed from the storage solution, it is recommended to immerse it in the liquid to be measured for a few minutes before measurement to improve accuracy.
b. Conduct measurements
Immersion in liquid: Fully immerse the electrode into the liquid to be tested, ensuring that the sensing part of the electrode is covered by the liquid.
Waiting for stability: Waiting for the reading on the display screen to stabilize usually takes a few seconds to minutes, depending on the properties and temperature of the liquid.
Read data: Record the stable pH value.
3. Processing after measurement
a. Clean electrode
After the measurement is completed, thoroughly clean the electrode with deionized water or distilled water to remove any residual substances.
b. Storage
Place the electrode in an appropriate storage solution (usually a dedicated electrode storage solution) to protect the sensitive membrane of the electrode and extend its service life.
Close and store the pH meter properly, avoiding direct sunlight and high temperature environments.
4. Maintenance and Precautions
Regular calibration: It is recommended to calibrate before each use, especially under high-precision measurement requirements.
Avoid severe vibration: Avoid severe shaking during operation to avoid affecting readings.
Temperature detection: pH value is related to temperature, ensuring use within the specified temperature range. If necessary, temperature compensation function can be used.
Regularly check electrodes: Regularly check and replace electrodes, especially when the measurement results are no longer stable.
5. Common problems and solutions
Unstable reading: Confirm electrode cleanliness and check if it is soaked in a suitable liquid; If the problem persists, it may be necessary to replace the electrode.
Unable to calibrate: Check if the buffer is expired or contaminated to ensure that the pH meter is working properly.
Display screen unresponsive: Check battery level and replace battery if necessary.