pH meter measurement problems and electrode problems and technical exchanges
1, PH meter measurement issue:
1. Is the pH value of the same sample different between two measurements?
Temperature changes or chemical reactions within the sample itself can cause changes in pH value. So, it is advisable to maintain consistent temperature and avoid chemical reactions as much as possible.
2. The same sample is measured on two pH meters at the same time, but the readings are inconsistent?
Due to the different calibration conditions of the two pH meters (such as calibration done at different times), there are differences in the measured values. So it is necessary to calibrate the pH meter with the same buffer solution at the same time, and then measure it simultaneously.
3. No matter what sample the electrode is in, the display remains unchanged?
I. Because the electrodes are not truly connected to the instrument. The processing method is to first shut down, and then reconnect the electrode and instrument.
II. Because the electrode is damaged, it is necessary to replace it with a new one in a timely manner.
4. Is the measurement unstable and takes a long time?
I. Because the electrodes are aging. The response time of the electrode in the buffer solution can be tested. If it is greater than 1 minute, the electrode needs to be activated or replaced with a new electrode.
II. If the response time of the measuring buffer is short but the measured sample is unstable, it indicates that the electrode is not suitable for measuring the tested sample. Please choose the appropriate electrode according to the electrode selection guide.
5. Is the pH value displayed on the instrument at 10 ℃ or 25 ℃ when the sample temperature is 10 ℃?
The acidity meter displays the pH value of the solution at the current temperature; If measured at 10 ℃, the instrument displays the value of the solution at 10 ℃; If a pH of 25 ℃ is required, the solution temperature must be raised/lowered to 25 ℃ before measurement.
The temperature compensation of an acidity meter refers to compensating for the effect of temperature on the pH electrode, but cannot compensate for the pH value at any temperature up to 25 ℃.
PH meter electrode issue:
1. How often do electrodes need to be calibrated?
The calibration frequency of electrodes depends on specific factors such as electrode usage, maintenance, sample properties, and measurement accuracy. It is recommended to calibrate once a day; The longest calibration should not exceed once a week. Electrode replacement and long-term disuse must be calibrated before use.
2. How long is the lifespan of pH electrodes?
The lifespan of pH electrodes is related to the properties of the measured sample, sample temperature, frequency of use, and maintenance. Under normal use and proper maintenance, the lifespan of pH electrodes is 1 to 2 years.
