Used as a sensitive analytical reagent for the spectrophotometric determination of trace amounts of metal ions, particularly cobalt (Co(II)), copper (Cu(II)), and nickel, in environmental and biological samples. Forms stable, colored complexes with these metals, allowing detection at low concentrations. Its high selectivity and sensitivity make it valuable in quality control processes in metallurgy, pharmaceuticals, and wastewater analysis. Also employed in the development of sensors and assays where color change indicates metal ion presence.