Compleometría

Compleometría is a term used in analytical chemistry to describe the quantitative determination of a metal ion through its complexation reaction with a chelating agent. This method is a type of titration where the equivalence point is detected. Commonly, ethylenediaminetetraacetic acid (EDTA) is used as the chelating agent due to its ability to form stable complexes with a wide range of metal ions. The metal ion to be determined is reacted with a standard solution of EDTA, and the reaction proceeds until all the metal ions have been complexed. The endpoint of the titration is usually indicated by a change in color of a metallochromic indicator, which forms a colored complex with the metal ion. When all the metal ions are bound by EDTA, the indicator is released and undergoes a color change. Compleometría can be used to determine the concentration of various metal ions in water, pharmaceuticals, food products, and geological samples. Variations of the method exist, including direct titration, back titration, and displacement titration, each suited for different types of samples and metal ions. The accuracy of compleometría depends on factors such as the stability of the metal-EDTA complex, the selectivity of the indicator, and the precise control of pH.