Determination of aliphatic amines using fluorescence intensity of 4-methyl umbelliferone

Effect of aliphatic amines and their concentration on fluorescence intensity of 4-methyl umbelliferone (4-MU) one of coumarin derivative were investigated. This compound has blue light emission under UV lamp in methanolic solution. Spectral investigation of 4-MU solution containing amine compounds showed lower intensity at 350–410 nm (quenching region) and higher intensity at 430–500 nm (enhancing region) as compared to pure methanolic solution of 4-MU. Fluorescence intensity at isoemitting point was independent from concentration of amines. The variation of fluorescence intensity could be used for determination of aliphatic amines in both quenching and enhancing region. Linear ranges for determination of amines in the quenching region were obtained from Stern-Volmer diagram of 4-MU. Determination of amines at fluorescence enhancing region using inverse fluorescence intensity against inverse amine concentration (bireciprocal plot) were investigated and related equations was also proposed.