kompleksomeetrilist

Kompleksomeetrilist, often referred to as complexometric titration, is a method of volumetric analysis used to determine the concentration of a metal ion in solution. The principle behind this technique relies on the formation of a stable, colored complex between the metal ion and a complexing agent, typically a chelating agent. The most common chelating agent used in complexometric titrations is ethylenediaminetetraacetic acid, or EDTA.

In a typical complexometric titration, a known volume of the sample containing the metal ion is placed in a flask. A suitable indicator is added, which forms a colored complex with the metal ion, or a free complexing agent, depending on the specific indicator. The titrant, a solution of the complexing agent (e.g., EDTA) of known concentration, is then added from a burette. As the titrant is added, it reacts with the free metal ions in the solution, forming a colorless metal-EDTA complex. The indicator's color remains unchanged until all the free metal ions have reacted. At the endpoint of the titration, when all the metal ions are complexed by EDTA, the indicator is displaced from the metal ion by the excess EDTA, causing a distinct and sharp color change. This color change signals the completion of the reaction. The volume of titrant used at the endpoint is then used to calculate the concentration of the metal ion in the original sample, based on the stoichiometry of the reaction and the known concentration of the titrant. Complexometric titrations are widely used in analytical chemistry for the quantitative determination of various metal ions such as calcium, magnesium, zinc, and copper in diverse samples, including water, pharmaceuticals, and food products.