Reasons for Inaccurate Measurement Readings of Mettler pH Meters
1, Mettler pH meter or pH electrode damaged
If we use a Mettler pH meter to measure the pH value of Mettler standard buffer solution, the pH meter reading does not change. For example, when using a Mettler pH meter FE20K to measure the pH values of Mettler pH 4.01 buffer solution and Mettler pH 7.0 buffer solution, FE20K remains unchanged. If the power supply and electrode cable are connected correctly, it means that there is a problem with the FE20K host or its standard pH electrode LE438, and the host or pH electrode needs to be repaired.
2, Mettler pH electrode malfunction
As mentioned in the first point above, it is also possible that the LE438 electrode has lost its activity and requires activation treatment. After activation, it will return to normal. For specific operating steps, please refer to the previous introduction on pH electrode activation on Mettler Instrument Network.
3, Inaccurate reading of Mettler pH meter caused by temperature or sample changes
Sometimes, after measuring the pH value of a sample at a certain point in time, we obtain a pH data. After a period of time, we take the same sample for measurement, and there may be changes in the pH value. Mettler Instrument Network has also received similar consultation calls before. This is mainly caused by changes in temperature or the sample itself, which requires maintaining a constant temperature in the measurement environment. After measuring the sample, attention should be paid to preservation.
4, Improper calibration of Mettler pH meter causes reading differences
When calibrating the Mettler pH meter, if the wrong calibration buffer group is selected, or if the calibration is not performed at 25 ℃ without temperature compensation, it will cause differences in the measured values.
