A new micelle-based method to quantify the Tween 80® surfactant for soil remediation

Tween 80® is a surfactant widely employed to enhance remediation of contaminated soils. Actually, there are few convenient and selective methods to quantify Tween 80® at low concentrations. Here, we report a new and simple quantification method to monitor Tween 80 ® analysis. Our method is based on the enhancement of the fluorescence of 6-(p-toluidino)naphthalene-2-sulfonic acid (TNS) by formation of micelles with Tween 80®. Results show a linear calibration curve with a correlation coefficient R 2 of 0.99, a detection limit of 0.13 mM and a quantification limit of 0.19 mM. This method showed better performances compared to actual methods such as UV absorbance and total organic carbon measurements. In addition, we demonstrated that the measurements using this new technique are impacted only at 3.5 % maximum by the presence of oxidation by-products formed during oxidation of Tween 80® by the electro-Fenton process or by hydrophobic organic contaminants present in solution. Fluorescence measurements of soil washing solution with real contaminated soil show almost no impact on Tween 80®-TNS micelle analysis. The analytical method proposed for Tween 80® analysis could replace the currently used conventional method because it is quite simple, highly sensitive and more selective.