Standard solution is a titration solution commonly used in volumetric analysis to measure the content of the substance to be measured and the concentration of the unknown solution. Standard titrations generally refer to solutions with known concentrations. In the testing process, the accuracy of the standard titrant concentration will directly affect the analysis results. In order to ensure the accuracy and reliability of the test results, the accuracy and credibility of the standard titrant concentration used should be strictly grasped.

Therefore, the accurate preparation and calibration of the standard titrant to ensure the accuracy of its concentration is a crucial work procedure for a quality inspection department. The following is a small edition of Bolinda to introduce you to the preparation and calibration of common standard solutions.

Preparation and calibration of common standard solutions:

1. Calibration of standard solution

The reference substances such as the acid, alkali or the corresponding salt with strong solubility are dissolved in the volume bottle with double distillation deionized water, and the volume is fixed to the required storage solution, the concentration is (mol/L), and the clean container is selected according to the requirements, the label is attached, and the storage is required by the specification.

2. Calibrate the substance

The pure reagent of the reference material should be selected as the calibration material, which should be dried to constant weight before calibration and accurately weighed.

3. Calibration process

In the calibration process of the standard solution, the two-person double-parallel calibration is strictly carried out, and the standard solution is calibrated and calculated with an accurate calibration substance. When the error is small and the data is quite close, the average value is the concentration of the standard solution.

4, calibration time

At normal temperature 1.000mol/L and above concentration of stored liquid should be calibrated once every 2a; 0.5000mol/L concentration of stored liquid should be calibrated once every 1a; The 0.1000mol/L concentration of stored liquid should be calibrated once every 6 months; Applications with concentrations below 0.1000mol/L should be calibrated every 3 months.

The above content is an introduction to the preparation and calibration of commonly used standard solutions. Self-formulated standard solutions as working standard solutions are generally used for daily inspection and analysis, and are not used for other test results with legal effects.

Unless it can be shown that its properties as a reference standard for measurement do not fail. When necessary, the self-prepared standard stock solution with large usage should be compared with the certified standard material within the validity period to avoid chemical changes and ensure the accuracy of the self-prepared standard solution quantity value.