Used as a sensitive analytical reagent for the colorimetric detection of metal ions, particularly copper(II) and iron(III). It forms highly colored complexes with these metals, allowing for visual or spectrophotometric determination at trace levels. Commonly applied in environmental monitoring to assess metal contamination in water and soil samples. Also utilized in developing test strips or sensors due to its distinct color change upon metal binding. Shows potential in pharmaceutical analysis for detecting metal impurities in formulations.