This method is standard. Another standard fluorimetric method. The fluorometric method for measuring the mass concentration of anionic surfactants is based on the extraction of ion pairs of anionic surfactants with an acridine yellow dye with chloroform, measuring the fluorescence intensity of the obtained extract on the analyzer, and automatically calculating the concentration of anionic surfactants using a calibration characteristic stored in the analyzer's memory. It is advisable to apply these two standard methods before the CMC of a surfactant. Then the hydrophobic interaction during the formation of ion pairs between the dye and the surfactant is greater.

for anionic surfactants with aromatic moiety UV-spectroscopy can be used. However, you have to expect serious interference from e.g. humic substances. Therefore it is better to use UV-Derivative spectroscopy to limit back ground effects. A comfortable solution would be use of surfactant selective electrodes.

Despite possible interferences MBAS method has the advantage that you first extract and thereby clean the analyte. A more powerful method would be use of HPLC were there is a broad literature.

Dear all, for more information please check the following documents. My Regards

https://doi.org/10.1080/03067317608071124

DOI: 10.1134/S1061934814010043

https://doi.org/10.1039/AN9881300747

https://doi.org/10.1021/ac00254a039

https://doi.org/10.1016/j.microc.2014.11.002