RLS DETERMINATION OF ANIONIC SURFACTANTS WITH RHODAMINE B

By the formation of ion association complexes through the reaction of rhodamine B with anionic surfactants (ASF) in a B-R buffer medium,an increase of magnitude of intensity of resonance light scattering (abbreviated as RLS) was observed.Based on this phenomenon,a new method for the determination of ASF was proposed.Optimum conditions for the reaction were studied and described taking sodium dodecyl sulfonate (SDS) and sodium dodecyl benzene sulfonate (SDBS) as testing objective anionic surfactants.As shown by experimental results,the peak maxima of RLS of the complex of rhodamine B and SDS was found at 518 nm (pH 3.0),and that of rhodamine B and SDBS at 373 nm (pH 3.4),where the measurements of IRLS were taken in the determination of SDS and SDBS.Detection limits of 0.023 and 0.038 mg·L-1 were obtained for SDS and SDBS respectively.In its application to the analysis of some environmental samples,recoveries in the range of 94.0% to 105.0% were obtained.Results obtained by this method were found to be in conformity with those obtained by the methylene blue method.