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Your location: Home > Related Articles > Interpretation of Titrator Electrode Judgment Tips-

Interpretation of Titrator Electrode Judgment Tips-

Author:QINSUN Released in:2023-05 Click:112

1. General inspection method of glass electrode

1. Zero potential check

Set the pH meter to the \"mV\" measurement position, insert the glass electrode and the reference electrode into the pH=6.86 in the buffer solution, the instrument reading should be around -50~50mV.

2. Check the slope:

Measure the mV value of the buffer solution with pH=4.00 or pH=9.18, and calculate the slope of the electrode. The relative slope of the electrode should generally be associated with technical indicators.

Note:

(1) The method of checking the zero potential value of the electrode is only for the glass electrode whose equipotential point is 7. If the glass electrode equipotential point is not 7, it will be different.

(2) For some pH meters, when the calibration and adjustment can meet the requirements, and the above inspection results are not out of range, the electrod can be used.

(3) For some smart pH meters, you can directly refer to zero potential and slope values ​​obtained from the instrument calibration results.

2. Reference electrode inspection method

1. Internal resistance inspection method

Use a laboratory conductivity meter and a end of the conductivity electrode socket the measuring device is connected to the reference electrode. The other end of the reference electrode is connected to a metal wire, and the reference electrode and the metal wire are immersed in the solution at the same time, and the measured internal resistance should be less than 10kΩ. If the internal resistance is too large, it means the liquid junction is blocked and needs to be addressed.

2. Inspection of electrode potential

Take a good reference electrode of the same model and the reference electrode measured in.ur connect to the input ends of the pH meter, then insert the KCl solution at the same time (or buffer solution with pH=4.00), the measured potential difference should be -3~3mV, and the change of potential must be less than ± 1 mV. Otherwise, the reference electrode must be replaced or regenerated.

3. Appearance check

The silver-silver chloride wire must be dark brown. If it is off-white, it means the silver chloride has been partially dissolved.

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