基于光纤折射率传感原理的表面活性剂临界胶束浓度测定方法

提出并研究了一种新颖的基于光纤折射率传感原理的表面活性剂临界胶束浓度(cmc)测定方法.应用此方法测定有代表性的阴离子表面活性剂十二烷基硫酸钠(SDS)与阳离子表面活性剂十六烷基三甲基溴化铵(CTAB)在25℃下的cmc分别为8.05×10-3和9.11×10-4mol·L-1,与文献值比较,结果相当吻合.从而证实了本方法的准确性.进一步研究了各种条件对测量表面活性剂cmc的影响,结果表明温度和无机盐NaCl的加入对本方法测量的准确性影响小,证明了本方法对测试环境的要求不苛刻,适用性好.最后对本方法进行了重复性和稳定性测试,相对标准偏差(RSD)为0.17%,与预期符合,效果良好.

Determination of Surfactant cmc Based on the Fiber Refractive Index Sensor Principle

Anovelmethod for the determination of surfactant criticalmicelle concentration (cmc), based on the fiber refractive index sensor principle was studied. The cmc of a representative anionic surfactant sodium dodecyl sulfate (SDS) and the cmc of a cationic surfactant cetyltrimethylammonium bromide (CTAB) were found to be 8.05×10^-3 and 9.11×10^-4 mol·L^-1 respectively at 25 ℃ using this method, which are in good agreement with literature values. Further determinations of surfactant cmc under various conditions show that the influence of temperature and the inorganic salt NaCl on the accuracy of the method is slight. Therefore, the applicability of the method is proven. We also tested the repeatability and stability of this method. The relative standard deviation (RSD) for the measurement results was 0.17%, which is consistent with our expectation.