Analysis of Cationic Surfactants by Microbore High-Performance Liquid Chromatography−Electrospray Mass Spectrometry

In the work reported here, a state-of-the-art analytical method for the quantitative analysis of cationic surfactants in environmental matrixes is described. High-performance liquid chromatography on-line coupled via an electrospray interface to a mass spectrometer (HPLC-ESP-MS) is used for the determination of ditallowdimethylammonium chloride (DTDMAC) and two of its most important substitution products, diethylester dimethylammonium chloride (DEEDMAC) and Diesterquaternary (DEQ). Using the analytical method developed in our laboratory, it is possible to determine single homologues of these surfactants as well as the first hydrolysis products of DEQ and DEEDMAC. In combination with our extraction procedure, which is based on ion-pair extraction, cationic surfactants were determined in environmental samples (sewage influent, sewage effluent, river water); concentrations ranged from 0.4 to 140 μg/L. The linear dynamic range of the HPLC-ESP-MS method, which is an injected amount between 0.4 and 30 ng, is well suitable for the analysis of these samples, as well as the performance of the quantification through external standards.