籍疏水花菁染料的荧光突变测定非离子表面活性剂临界胶束浓度

研究了近红外疏水花菁染料I在几种表面活性剂溶液中的荧光行为. 花菁I在水中及含有低浓度(小于临界胶束浓度,CMC)的曲通X-100溶液中表现出很弱的荧光,但当表面活性剂浓度达到CMC时,荧光显著红移并迅速增强到最大.这种荧光突变为曲通X-100的胶束形成提供了直观的指示,可据此建立一种测定其CMC的简单荧光方法.该法还适用于Brij-35的CMC测定,所测的CMC值与文献报道的结果十分吻合.

ESTIMATION OF THE CRITICAL MICELLE CONCENTRATION OF NONIONIC SURFCTANTS BASED ON THE FLUORESCENCE MUTATION OF A NEAR-INFRARED HYDROPHOBIC CYANINE DYE

The fluorescence behavior of the near-infrared (NIR) hydrophobic Cyanine I, in aqueous solution containing different surfactants, was studied. Cyanine I exhibited a weak fluorescence in water and aqueous solution containing a low concentration (below the critical micelle concentration, CMC) of surfactant Triton X-100. However, the fluorescence enhanced and reached maximum rapidly with a large red-shift of maximal emmision wavelength when the concentration of the surfactant approaches the CMC. This fluorescence mutation gives a direct indication for the micelle forming process and provides a simple and rapid method for the determination of the critical micelle concentration of the surfactant. The method could also be applied for the CMC measurement of other nonionic surfactants such as Brij-35. The CMC values determined by this method are in good agreement with those obtained by other techniques.