利用荧光素异硫氰酸酯检测季铵盐阳离子表面活性剂的方法

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。

Concentration characterization of quaternary ammonium surfactants by FITC

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.