Used as a sensitive reagent for the detection and colorimetric determination of trace metals, especially lead and mercury, in environmental, biological, and industrial samples. The solution forms colored complexes with metal ions, allowing for visual or spectrophotometric analysis. Commonly applied in qualitative spot tests and extraction procedures due to its selectivity and the distinct color changes it produces in the presence of target metals. Also utilized in separation techniques where metal ions are extracted into the organic phase for further analysis.