Reasons why Mettler pH meter readings are inaccurate
1. Mettler pH meter or pH electrode is 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, a Mettler acidometer FE20K is used to measure Mettler pH 4.01 buffer solution and Mettler pH 7. When the pH value of the buffer solution is .0, the FE20K keeps the reading 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 failure
As mentioned in the first point above, it is also possible that the LE438 electrode has lost its activity and needs activation treatment. After activation, it will return to normal. For specific operation steps, you can refer to the previous introduction on pH electrode activation on the Mettler Instruments website. .
3. Changes in temperature or the sample itself cause inaccuracies in Mettler pH meter readings
Sometimes, after we measure the pH value of a sample at a certain point in time, we get a pH data. After a period of time, we take the same sample and measure it again. The pH value may change. Previously, Mettler instruments I have also received similar consultation calls online. This is mainly caused by changes in temperature or the sample itself, which requires keeping the temperature of the measurement environment constant. After measuring the quantitatively changed sample, pay attention to saving it.
4. Improper calibration of Mettler pH meter causes reading differences
When calibrating a Mettler pH meter, if the wrong calibration buffer set is selected, or the calibration is not performed at 25°C and is not temperature compensated, there will be differences in the measured values.
