Gravimetriska

Gravimetriska, or gravimetric analysis, is an analytical approach in chemistry and related fields that determines the amount of a substance by measuring its mass. The method relies on converting the target analyte into a pure, insoluble solid of known composition, which can be separated from solution and weighed accurately.

The principle involves forming a stable precipitate or a volatile product that contains the analyte in a defined chemical form. The solid is isolated by filtration, washed to remove impurities, and dried or ignited to a constant mass. Using the mass of the solid and its known chemical formula, the amount of the original substance can be calculated. Key steps often include selecting a specific precipitating agent, achieving quantitative precipitation, and ensuring minimal co-precipitation or adsorption of impurities.

Common precipitates used in gravimetric analysis include barium sulfate for sulfate determinations, silver chloride for chloride content, and various metal oxides or salts for other cations. The quality of the result depends on the completeness of precipitation, the purity of the solid, and the accuracy of the mass measurement. A frequent refinement is ignition of the precipitate to transform it into a stable oxide or other form with a precisely known mass.

Gravimetric methods are valued for their accuracy and independence from volume measurements, but they can be time-consuming and are most practical for relatively pure samples and for analytes that form easily isolable, stable solids. They are used in environmental, mineralogical, pharmaceutical, and industrial analyses where high precision is required.