conductivity standardIt is necessary for titration analysis, and the content of the analyte is calculated based on the concentration of the substance in the standard solution and the volume consumed during titration. Therefore, the accuracy of the concentration of the standard solution is one of the main factors affecting the accuracy of titration analysis results.
conductivity standardAs a requirement for reference materials:
The reagent must have a sufficiently high purity, generally requiring a purity of over 99.9%, and the impurities contained should not affect the accuracy of the titration reaction.
The actual composition of a substance should match its chemical formula *, and if it contains crystal water, the number of crystal water should also match its chemical formula *.
The reagent should be stable. For example, it is not easy to absorb moisture and carbon dioxide from the air, not easily oxidized by air, and not easily decomposed when heated and dried.
The reagent has a large molar mass, which can reduce weighing errors.
conductivity standardThere are usually two preparation methods:
Direct method. Accurately weigh a certain amount of substance, dissolve it and transfer it quantitatively to a volumetric flask, dilute to the mark, and shake well. Calculate the accurate concentration of the standard solution based on the mass of the substance being weighed and the volume of the volumetric flask. The substance of this standard solution should meet the following conditions:;
Very high purity Usually, the impurity content should be less than 0.01%, and the main grade should be greater than 99.99%
The composition of the substance should conform to the chemical formula *.
stable;
The molar mass is relatively large.
Application method of conductivity standard solution:
Firstly, take a large amount of calibration solution to rinse a small cup, and then add excess calibration solution (the liquid level should be below the electrode's sensing probe)
Calibrate according to the instructions for using the electronic pH test pen.
Due to the fact that calibration solution is a high-precision liquid that ensures the accuracy of electronic pH testing pens, used calibration solution cannot be poured back into the bottle to avoid affecting the accuracy of the calibration solution, introducing bacteria, etc., and causing the calibration solution to be unable to be continuously used.