Sekundærstandarder

Sekundærstandarder are materials or solutions in analytical chemistry that have been standardized against a primary standard. Unlike primary standards, secondary standards do not meet the stringent requirements of being highly pure, stable, and having a well-defined molecular weight. Instead, their concentration is determined by titration or another analytical method using a known quantity of a primary standard.

The process of standardizing a secondary standard involves preparing a solution of approximate concentration and then carefully titrating it with a primary standard. This allows for the precise determination of the secondary standard's exact concentration. Once standardized, the secondary standard can be used for routine analyses, such as titrating unknown samples. This is often more practical than using a primary standard for every analysis, as primary standards can be less stable or more difficult to handle.

Common examples of secondary standards include solutions of sodium hydroxide (NaOH) or hydrochloric acid (HCl). While these are readily available, their purity and stability may not be sufficient for direct use as primary standards. Therefore, they are typically standardized against primary standards like potassium hydrogen phthalate (KHP) for bases or silver carbonate (Ag2CO3) for acids. The use of secondary standards streamlines laboratory procedures and allows for efficient and accurate quantitative analysis in various chemical applications.