Is the standard solution available for purchase?

      

　　Can standard solutions be purchased?standard solutionNon-dangerous goods can be purchased on the Internet, and standard solution purchases can be purchased www.gbw.org.cn National Standard Products Network. Note that the National Standard Products Network is a website that provides various standard reagents, such as standard solutions (ICP, heavy metals, multi-elements, pesticide residue standard solutions). The standard solutions on its website are all nationally recognized products, which can be certified and declared for use. There is a quality inspection certificate with the goods.

　　Extended reading: A standard solution refers to a solution with a known exact concentration. It is often used as a titrant in titration analysis. In other analytical methods, standard solutions are used to draw working curves or calculate standards.

　　There are two preparation methods, one is the direct method, that is, accurately weighing the reference material, bandwidth evaluation to a certain volume after dissolution; the other is the calibration method, that is, first formulated to an approximate required concentration, and then the reference material or a standard solution to calibrate.

　　A solution of known exact concentration is used as a titrant in volumetric analysis to titrate the substance under test.

　　If the reagent meets the requirements of the reference substance (composition is consistent with the chemical formula, high purity and stability), the standard solution can be directly prepared, that is, an appropriate amount of the reference substance can be accurately weighed, and it can be prepared in a volume bottle after dissolution. The weight of the reference substance to be weighed can be calculated by the following formula: W = M V · The molar mass of the reference substance. In the formula, M and V are the molar concentration and volume of the solution to be prepared, respectively. The concentration of the standard solution can be calculated by using the above formula.

　　If the reagent does not meet the requirements of the reference substance, a solution that approximates the required concentration is first prepared, and then its concentration is accurately determined with the reference substance. This process is called solution calibration.