title: Use of shift gradient in the second dimension to improve the separation space in comprehensive two-dimensional liquid chromatography.
abstract: Comprehensive two-dimensional liquid chromatography (LC × LC) has received much attention because it offers much higher peak capacities than separation in a single dimension. The advantageous peak capacity makes it attractive for the separation of complex samples. Various gradient methods have been used in LC × LC systems. The use of continuous shift gradient is advantageous because it combines the peak compression effect of full gradient mode and the tailed gradient program in parallel gradient mode. Here, a comparison of LC × LC analysis of Chinese herbal medicine with full gradient mode and shift gradient mode in the second dimension was performed. A correlation between the first and second dimensions was found in full gradient mode, and this was significantly reduced with shift gradient mode. The orthogonality increased by 43.7%. The effective peak distribution area increased significantly, which produced better separation.
authors.affiliation: Applied Analytical Chemistry, Faculty of Chemistry, University of Duisburg-Essen, Essen, Germany.
authors.forename: Duxin
authors.initials: D
authors.lastname: Li
authors.forename: Oliver J
authors.initials: OJ
authors.lastname: Schmitz