Used as a sensitive reagent for the spectrophotometric determination of trace amounts of secondary amines, particularly in environmental and biological samples. It forms highly colored complexes with secondary amines, allowing detection at low concentrations. Commonly applied in monitoring amine-containing pollutants and in pharmaceutical analysis where selective detection of amine metabolites is required. Also utilized in the synthesis of heterocyclic compounds and as a derivatizing agent in analytical chemistry due to its selective reactivity with amine groups.