Widely used as a sensitive analytical reagent for the spectrophotometric determination of trace metals, especially zinc, cobalt, and nickel in environmental, biological, and industrial samples. It forms highly colored complexes with these metals, allowing detection at very low concentrations due to high molar absorptivity. The color change upon metal binding makes it suitable for both visual and instrumental analysis. Commonly applied in water quality testing, pharmaceutical analysis, and metallurgical assays. Also used as an indicator in complexometric titrations and in the development of sensor materials for metal ion detection.