摘要
在弱酸性的HCl-NaAc缓冲介质中，阳离子表面活性剂（CS）与曙红Y（EY）染料反应，形成离子缔合物，溶液颜色发生明显改变，最大褪色波长分别在514nm（EY—CPB体系）、516nm（EY—CTAB体系），同时在548nm（CPB体系）、544nm（CTAB体系）处有吸收峰，在褪色波长处阳离子表面活性剂的浓度与褪色程度呈良好线性关系，从而建立测定阳离子表面活性剂的光度法。在最大褪色波长处，CPB体系、CTAB体系中CS的浓度在0～4．79×10^-5mol／L、0～2．90×10^-5mol／L范围内遵守比尔定律，表观摩尔吸光系数为2．94×10^4、2．86×10^4L·mol^-1·cm^-1，检出限为8．97×10^-7mol／L、7．87×10^-7mol／L。若用双波长叠加，表观摩尔吸光系数达5．58×10^4、5．20×10^4L·mol^-1·cm^-1，检出限为5．87×10^-7、6．25×10^-7mol／L。方法适用于水样中CS的测定。本文还用密度泛函理论对反应机理进行了探讨。
In weak acidic HCl - NaAc buffer medium, cationic surfactants （CS） react with eosin Y （EY） to form an ion-association complex, the colors of solutions change obviously, the maximum fading wavelength at 514 mn （EY- CPB system） and 516 mn （EY- CTAB system）, besides, there is a absorption peak at 548 mn （CPB system） and 544 nm （CTAB system）, the fading intensity is also proportional to the concentration of cationic surfactants at the maximum fading wavelength, a sensitive spectrophotometric method is developed for the determination of cationic surfactants. In CPB and CTAB system, the concentration of CS in the range of 0 ～ 4.79 × 10^-5 and 0 ～ 2.90 × 10^-5 mol/L obeys Beer＇s law at the maximum fading wavelength, the apparent molar absorptivity ε is 2.94× 10^4 and 2.86 × 10^4 L · mol^-1·cm^-1 , the detection limit is 8.97 × 10^-7 and 7.87 × 10^-7 mol/L, respectively. If the determination process is dealt with double wavelength, the apparent molar absorptivity is 5.58 × 10^4 and 5.20 × 10^4 L·mol^-1·cm^-1 , the detection limit is 5.87 × 10^-7 and 6.25 × 10^-7 mol/L, respectively. The method has high sensitivity and fairly good selectivity, and the method is applied to the determination of CS in water samples, with satisfactory results. In addition,the reaction mechanism by using density functional theory methods of quantum chemistry have been studied, calculated results and experimental results match mutually.
出处
《分析试验室》
CAS
CSCD
北大核心
2006年第10期110-114,共5页
Chinese Journal of Analysis Laboratory
