Widely used as a sensitive analytical reagent for the spectrophotometric determination of trace metals, especially cobalt, in environmental, biological, and industrial samples. Forms stable, intensely colored complexes with metal ions, allowing detection at low concentrations. Commonly employed in colorimetric assays due to its high molar absorptivity and selectivity when combined with surfactants or masking agents. Also utilized in the development of sensors and test strips for on-site metal analysis. Its sharp color change upon metal binding makes it suitable for endpoint detection in some titrations.