【摘要】 在弱酸性的NaH2PO4-Na2HPO4缓冲介质中,阳离子表面活性剂(CS)溴化十六烷基吡啶(CPB)、十六烷基三甲基溴化铵(CTAB)与依文思蓝(EB)染料反应,形成离子缔合物,溶液颜色发生明显改变,最大褪色波长位于610 nm。在最大褪色波长处,CS的浓度与褪色程度呈良好线性关系,从而建立了测定阳离子表面活性剂的光度法。在最大褪色波长处,CS的浓度在5.0×10-7~2.46×10-5mol/L(EB-CPB)、9.0×10-7~3.36×10-5mol/L(EB-CTAB)范围内遵守比耳定律,表观摩尔吸光系数为1.97×104L.mol-1.cm-1(EB-CPB)、1.25×104L.mol-1.cm-1(EB-CTAB),检出限为3.6×10-7mol/L(EB-CPB)、7.4×10-7mol/L(EB-CTAB)。本法用于水样中阳离子表面活性剂的测定,结果满意。更多还原

【Abstract】 In weak acidic NaH2PO4-Na2HPO4 buffer medium,cationic surfactants(CS),cetylpyridinium bromide(CPB) and cetyl trimethyl ammonium bromide(CTAB),react with evans blue(EB) to form ion-association complexes.The colors of solutions change obviously,and the maximum fading wavelength is at 610 nm.The fading intensity is also proportional to the concentration of CS,and a sensitive spectrophotometric method is therefore developed for determination of cationic surfactants.The concentration of CS in the range of 5.0×10-7~2.46×10-5 mol/L(EB-CPB)and 9.0×10-7~3.36×10-5 mol/L(EB-CTAB)obeys Beer’s law at the maximum fading wavelength.The apparent molar absorptivities are 1.97×104 L/(mol\5cm)(EB-CPB) and 1.25×104 L/(mol\5cm)(EB-CTAB).The detection limits are 3.6×10-7 mol/L(EB-CPB) and 7.4×10-7 mol/L(EB-CTAB).The method has high sensitivity and low detection limit,and has been applied to the determination of CS in water samples with satisfactory results.更多还原