When testing with a standard solution instead of a sample, the result should be consistent with the known concentration of the standard solution. If the results match, the test was performed correctly. If there is any significant deviation (greater than 10%) from the standard value, there is an error and analysis is required. So what are the ways to prepare the standard solution? The following is a small edition of Bolinda to introduce you.

How to prepare the standard solution:

1, direct preparation method

Accurately weigh a certain amount of reference material, dissolve it with an appropriate solvent, and then fill it into a volumetric bottle. If the reagent meets the requirements of the reference material (the composition is consistent with the chemical formula, high purity and stability), the standard solution can be directly prepared, and a certain amount of the dried reference substance can be accurately weighed on the analytical balance and dissolved in water, transferred to the corrected volumetric bottle and diluted with water to the scale, and shaken well to calculate its accurate concentration.

2. Calibration method

Many substances do not meet the biological conditions of the reference material and can not directly prepare the standard solution. Generally, these substances are first prepared into a solution of approximately the required concentration, and then the accurate concentration is determined with a reference substance. There are two calibration methods: direct calibration and indirect calibration. The systematic error of indirect calibration is larger than that of direct calibration.

The above content is the introduction of the preparation methods of the standard solution, the preparation and calibration of the standard solution have two standards, respectively, SH/T0079 "Preparation method of reagent solution for petroleum product testing" and GB/T601-2002 "Preparation of chemical reagent standard titration solution". We currently use SH/T0079.