Spectrofluorimetric Assay of Cationic Surfactants by Fluorescence Quenching of 9-Anthracenecarboxylic Acid

Abstract

A new simple, selective and sensitive fluorescence quenching method was developed to determine cationic surfactants with the 9-anthracenecarboxylic acid (ACA). The fluorescence intensity of ACA was decreased by addition of trace amounts of cationic surfactants. Under optimum conditions, the ratio of fluorescence intensity in the absence and presence of cationic surfactants was proportional to the concentration of cationic surfactants over the range of 0.3–4.5 × 10−5 mol L−1 for cetylpyridinium chloride (CPC) and 0.4–6.0 × 10−5 mol L−1 for cetyl trimethyl-ammonium bromide (CTAB). The detection limits are 1.0 × 10−6 mol L−1 for CPC and 1.2 × 10−6 mol L−1 for CTAB, respectively. Based on this approach, this paper presents a new quantitative method for cationic surfactants assay.