title: Reproducibility of retention time and peak area in comprehensive two-dimensional liquid chromatography.
abstract: Comprehensive two-dimensional liquid chromatography is used to separate anionic, nonionic, and amphoteric surfactants by substance class, alkyl chain distribution, and degree of ethoxylation. A nearly orthogonal system with a hydrophilic interaction chromatography (HILIC) phase in the first and a reversed-phase material in the second dimension is applied to generate a separation with maximum peak capacity. The potential of the developed method is demonstrated by the reproducibility of retention time and peak area, which shows standard deviations less than 5 % and the analysis of real samples. An external calibration and the standard addition method were applied to determine unknown concentrations for the alkyl chain homologues of a betaine and for one ethoxylate (EO) homologue of a fatty alcohol ethoxylate in a sample mixture.
authors.affiliation: Institute for Pure and Applied Mass Spectrometry, University of Wuppertal, Gaussstr. 20, 42119, Wuppertal, Germany.
authors.forename: Victoria
authors.initials: V
authors.lastname: Elsner
authors.forename: Volker
authors.initials: V
authors.lastname: Wulf
authors.forename: Michaela
authors.initials: M
authors.lastname: Wirtz
authors.forename: Oliver J
authors.initials: OJ
authors.lastname: Schmitz