刚果红与十六烷基三甲基溴化铵褪色反应的研究及应用

Study and application of fading reaction of Congo red with CTMAB

建立了测定十六烷基三甲基溴化铵（CTMAB）的分光光度方法。在pH6．0的HClNaAc缓冲溶液中，刚果红（CR）与CTMAB反应形成离子缔合物时，刚果红发生褪色作用，在最大褪色波长515nm处，褪色程度与CTMAB浓度在5．0×10^-6～4．0×10^-5mol／L范围内呈线性关系，表观摩尔吸光系数为1．29×10^4 L·mol^-1·cm^-1，检出限为1．5×10^-6mol／L。该方法用于环境水样中CTMAB含量的测定，相对标准偏差为1．2％～2．3％，回收率为97．29／6～103．0％。

A spectrophotometric method for determination of cetyl trimethyl ammonium bromide （CTMAB） was studied. In HCl-NaAc buffer solution at pH 6.0, fading reaction of Congo red （CR） occurred when forming ion complex with CTMAB. At maximal fading wavelength of 515 nm, the degree of fading is linear with CTMAB concentration in the range of 5.0×10^-6--4.0 ×10^-5 mol/L. The apparent molar absorptivity was 1.29 ×10^4 L · mo1^-1 · cm^-1 , and the detection limit was 1.5×10^-6 mol/L. This method was applied to the determination of CTMAB in environmental water samples with the relative standard deviation of 1.2%--2.3%, and the recovery of 97.2%--103.0%.