季胺盐型表面活性剂与镁试剂Ⅰ显色反应的研究及其分析应用

Study on the Chromogenic Reaction of Quaternary Ammonium Surfactants With (p-Nitrophenylazo)-resorcinol and Their Analytical Applications

本文研究了季胺盐型表面活性剂CPB、CTMAB以单分子及胶束形式与镁试剂I的显色反应.认为单分子或胶束与镁试剂I反应均为离子缔合机理,缔合比均为2:1,且造成镁试剂I的吸收光谱相同波数的红移,但形成胶束后(?)和镁试剂I的K_(?)(?)增加的更大.应用该显色体系测定了CPB、CTMAB的临界胶束浓度,探讨了微量CPB、CTMAB测定的可能性.

The mechanism, characteristics and analytical applications of the chromogenic reaction of (p-nitrophenylazo)-resorcinol (PNPAR) with cetylpyridinium bromide(CPB) or cetyltrimethylammonium bromide (CTMAB) were investigated. Both single molecular and micelle of surfactant could cause the equivalent red shift of the absorption spectrum of PNPAR. Their association ratio with PNPAR was 2 : 1. The influences of single molecular and micelle on pKa2 and εmax of PNPAR were different. Based on this chromogenic reaction, the critical micelle concentration of CPB and CTMAB was determined, and the possibility for the determination of trace CPB and CTMAB was proposed.