(阳离子表面活性剂-I3)n缔合微粒体系的光谱特性及分析应用

在0.01 mol/L HCl介质中,I-3在350 nm处有一吸收峰;当十六烷基三甲基溴化铵(CTMAB)与I-3共存时体系呈红紫色,在550 nm处产生一新的吸收峰.CTMAB浓度CCTMAB在0.0～7.0×10-5 mol/L范围内符合比耳定律,回归方程为A550 nm =0.989×104 CCTMAB+0.0138,相关系数R为0.999 5,摩尔吸光系数ε为1.06×104 L/(mol·cm),据此建立了一种测定阳离子表面活性剂含量的分光光度新方法,并用于合成样品和新洁尔净样品中阳离子表面活性剂测定.共振散射光谱研究表明,CTMAB+与I-3可通过静电引力作用形成疏水性的CTMA-I3缔合物分子,并进一步聚集形成稳定的 (CTMA-I3)n缔合微粒.由于该缔合微粒在580 nm处产生共振散射效应,故体系呈红紫色.

Spectral Properties of Cationic Surfactant-I3- Association Particle System and Its Analytical Application

In 0.01 mol/L HCl medium, there is a max absorption peak at 350 nm for I₃^-. The association particle system of (CTMAB-I₃)_n is in violet-red color. It has a new absorption peak at 550 nm. The CTMAB concentration C_CTMAB in the range of 0.0~7.0×10^-5 mol/L is linear to the A_550nm value. Its regression equation is A_550nm=0.989×10⁴ C_CTMAB+0.0138,regression coefficient is 0.9995. The mole absorption coefficient is 1.06×10⁴ L/(mol·cm). A new spectrophotometric method has been proposed for the determination of cationic surfactant. The resonance scattering spectra show that the CTMAB⁺ and I₃^- combine to CTMA-I₃ association molecule by means of attract forces. The association molecules automatically aggregate to (I₃-CTMA)_n association particles. So that, the particles exhibit a resonance scattering peaks at 580 nm, and the system is in violet-red.