Identification of Cationic and Anionic Surfactants by Chromatography-Mass-Spectrometry in the Microextraction-Fluorimetry Screening of Water and Food Products

A method is proposed for the identification of surfactants by ultra-performance liquid chromatography (UPLC) with high-resolution mass spectrometry detection after screening water and food samples for the total concentration of cationic and anionic surfactants by microextraction-fluorimetry. The method is based on the use of dispersive liquid-liquid microextraction with chloroform of surfactant ion pairs with organic reagents (eosin and acridine yellow), measuring the fluorescence of the obtained adducts using a smartphone, obtaining RGB colorimetric characteristics, and determining the total surfactant concentration. The main analytical characteristics of the identification of cationic surfactants (alkylpyrdinium, alkyltrimethylammonium, alkyldimethylbenzylammonium (benzalkonium), alkylmethylethylbenzylammonium, didecyldimethylammonium, benzyldimethyl[3-(myristoylamino)propyl]ammonium, N,N-bis(3-aminopropyl)dodecylamine chlorides) and anionic surfactants (alkyl benzene sulfonates (sulfonol), alkyl sulfates, laureth sulfates, alkyl sulfonates, and sodium alkyl carboxylates) by chromatography-mass spectrometry under the selected conditions of chromatographic separation and mass spectrometric detection are found. The features of the chromatographic behavior of the surfactant polymerhomologs under the conditions of UPLC and gradient elution are considered.

Automated summary

A method for identifying surfactants using UPLC with high-resolution mass spectrometry detection is proposed, after screening water and food samples for the total concentration of cationic and anionic surfactants by microextraction-fluorimetry. The method involves dispersive liquid-liquid microextraction of surfactant ion pairs with organic reagents, measuring fluorescence with a smartphone, obtaining RGB colorimetric characteristics, and determining surfactant concentration. Analytical characteristics for identifying cationic and anionic surfactants by chromatography-mass spectrometry are established under specific conditions, considering the chromatographic behavior of surfactant polymerhomologs under UPLC conditions and gradient elution.