The Determinatin Of Anionic Surfactants(ASF) With Rhodamine B-ASF System By Resonance Light Scattering Method

Anionic surfactants (ASF), especially dodecylsulphonic acid sodium salt (SDS) and dodecylbenzene sulphonic acid sodium salt (SDBS), which are important sorts of surfactants have been released into environment in large quantity, caused pollution of water and soil. So the determination of ASF in environment aroused more and more interests of researchers. Presently the main method of detecting ASF is methylene blue method, but because of the strict conditions, large amount of organic solvent which have some toxicity and volatility, and high LOD (0.05mg/L), it often could not detect the real content of ASF in the drinking water and the surface water.A new method has been developed for the determination of anionic surfactants (ASF) based on ASF reacting with Rhodamine B to form ion association complexes in buffer solution, which result in an increase of resonance light scattering. The maximum RLS peaks are at 518 nm (SDS) and 373 nm (SDBS). The effect of acidity, amount of RhB, and the coexistent substance to experiments had been investigated. The results illustrated that, the conditions is optimum when pH is 3.0(SDS) and 3.4(SDBS), and the volume of RhB is 1mL in the system. in the optimum conditions the method has very high sensitivity, Regression equation of SDS-RhB system is I=0.775C_SDS-0.76, linear range is 0.0-80.0μg/mL, and detection limit is 0.023μg/mL; Regression equation of SDBS-RhB system is I=1.613C_SDBS-0.16, linear range is 0.0-36.0μg/mL, and detection limit is 0.038...