Abstract:

Quaternary ammonium surfactants (QAS) are one of the most important surfactants in industry, pharmaceuticals and cosmeticsTheir rapid detection and accurate quantification plays a key role in controlling their application or existence in the environmentIn the present study, a novel method was established to detect the critical micelle concentration (CMC) of QAS in water and to quantify the surfactant concentration below its CMC, based on the fluorospectrum and fluorescence intensity change of fluorescein isothiocycanate (FITC)This approach was simple and sensitive, achieving the limit of detection (LOD) of dodecyltrimethylammonium bromide (DTAB) and cetyltrimethylammonium bromide (CTAB) at 0.11 mmol·L^-1 and 1.7 μmol·L^-1, respectivelyAnd the quantification range of DTAB and CTAB was 0.11—9.73 mmol·L^-1(0.034—3.0 g·L^-1) and 1.7 μmol·L^-1—0.27 mmol·L^-1(6.2×10^-4—0.1 g·L^-1), respectivelyThe CMCs were detected as 12—13 mmol·L^-1(DTAB) and 0.70—0.96 mmol·L^-1(CTAB), which were consistent with the results measured by the conductance, surface tension of the solution or by the pyrene probeConcentration characterization of the QASwater solution by FITC has provided a new, safe, simple and accurate approach to analyzing and monitoring the surfactants in the environment or in their wide application.

Key words:

荧光素异硫氰酸酯, 季铵盐阳离子表面活性剂, 荧光探针, 临界胶束浓度

摘要：

使用荧光素异硫氰酸酯（FITC）实现了对季铵盐阳离子表面活性剂（QAS）在水溶液中临界胶束浓度（CMC）的准确测量及其在CMC以下的浓度定量。用该法测得十二烷基三甲基溴化铵（DTAB）和十六烷基三甲基溴化铵（CTAB）在水中的CMC分别为12～13 mmol·L^-1和0.70～096 mmol·L^-1，与电导率法、表面张力法和芘荧光法的检测值相近。对DTAB和CTAB的检测下限分别是011 mmol·L^-1和1.7 μmol·L^-1，定量范围分别为0.11～9.73 mmol·L^-1（0.034～3.0 g·L^-1）和1.7 μmol·L^-1～0.27 mmol·L^-1（6.2×10^-4～0.1 g·L^-1）。结果表明，使用FITC荧光探针检测QAS具有安全、简便、灵敏度和准确度高的优点。

关键词:

荧光素异硫氰酸酯, 季铵盐阳离子表面活性剂, 荧光探针, 临界胶束浓度