Standard solution is a titration solution commonly used in volumetric analysis, by which the content of the substance to be measured can be measured and the concentration of the unknown solution can be obtained. Combined with the analysis of the chemical testing industry, this paper summarizes some problems that should be paid attention to in the configuration and calibration process of the standard solution, and the following small series of Bolinda to give you a detailed introduction.

What problems should be paid attention to in the configuration and calibration process of standard solution:

1, the water used in the preparation of the solution, when no other requirements are indicated, should meet the GB6683 level 3 water specifications. The ethanol used is 95% ethanol.

2. The reagents used for calibration solution and preparation of reference solution are reference reagents for capacity analysis. The purity of the reagents used in the preparation of general solutions is not less than that of analytical purity.

3. The weights, burets, volumetric bottles and pipettes of analytical balances used in solution preparation shall be regularly verified according to the requirements of metrological verification regulations.

4, the quality of the reagent taken in the preparation of the solution should be within the specified quality of ±10%.

5, calibration standard titration solution concentration, the difference between the concentration value of a single calibration and the arithmetic mean should not be greater than 0.2% of the arithmetic mean. At least the arithmetic mean of the three calibration results is taken as the actual concentration of the standard titration solution.

6, the concentration of standard titration solution and reference solution takes four significant digits.

7. The difference between the concentration value of the standard titration solution prepared and the specified concentration value should not be greater than ±5% of the specified concentration value.

8. When calibration and comparison are used to calibrate the solution concentration, the calibration method shall prevail if there is any dispute.

The above content is the introduction of the problems that should be paid attention to in the configuration and calibration process of the standard solution. In addition, there are two methods for the extraction of the standard solution, mainly the direct preparation of the reference substance and the calibration and extraction of the standard solution with known accurate concentration. The accuracy of the concentration of the standard solution is directly related to the precision and accuracy of the detection results. Its preparation conditions have very strict requirements.