Kompleksometri

Kompleksometri is a method used in chemistry to determine the concentration of a complex compound in a solution. This technique is particularly useful when dealing with metal complexes, where a metal ion is bound to one or more ligands. The process involves the formation of a colored complex, which can then be measured spectrophotometrically.

The principle behind kompleksometri is based on the Beer-Lambert law, which states that the absorbance of a solution is directly proportional to the concentration of the absorbing species and the path length of the light through the solution. By measuring the absorbance at a specific wavelength, the concentration of the complex can be calculated.

The choice of ligand is crucial in kompleksometri. The ligand should form a stable and colored complex with the metal ion, and the complex should have an absorbance maximum in the visible or near-infrared region of the spectrum. Commonly used ligands include EDTA (ethylenediaminetetraacetic acid) and DCTA (diethylenetriaminepentaacetic acid).

The procedure typically involves adding a known amount of the ligand to a solution containing the metal ion. The mixture is then allowed to reach equilibrium, and the absorbance of the resulting complex is measured. The concentration of the complex is then calculated using the Beer-Lambert law.

Kompleksometri has several advantages, including its simplicity and the ability to measure low concentrations of metal ions. However, it also has limitations, such as the need for a stable and colored complex and the potential interference from other species in the solution. Despite these limitations, kompleksometri remains a valuable tool in analytical chemistry for the determination of metal complexes.