Application of fractionized sampling and stacking for construction of an interface for online heart-cutting two-dimensional liquid chromatography

Advances and challenges in ginseng research from 2011 to 2020: the phytochemistry, quality control, metabolism, and biosynthesis

“…The phytochemical advances in the Panax genus, aside from the saponins and polysaccharides, also include the following components: (1) a new phenolic glucoside, isoconiferoside, from the seeds of P. ginseng; 171 (2) a new aliphatic alcoholic acid, 14a,15a,16a,17a,18a,19a,20a,21a-octahydroxy-16,17,18- [178][179][180][181][182][183] One merit for the off-line 2D-LC is the exible conguration of two columns with different mechanisms of separation, to pursue the highest orthogonality, but without the consideration of solvent incompatibility in combining hydrophilic interaction chromatography (HILIC) and reversed-phase chromatography (RPC), which is particularly suitable for the in-depth proling and characterization of ginsenosides from different ginseng species. The integration of XAmide/BEH C18, 48 XBridge Amide/ BEH C18, 100 and XBridge Amide/BEH Shield RP18, 177 could achieve the orthogonality of 0.81, 0.79, and 0.69, respectively, while the theoretical peak capacity (the product of the peak capacity in each dimension) reached 10 200, 11 000, and 8925, respectively.…”

“…In the past decade, at least eight studies used 2D-LC to analyze ginsenosides in herbal medicines and ginseng-related products in either the off-line 49,104,177 or on-line mode. 178–183…”

“…An interface was developed, based on a fractionized sampling and stacking strategy, providing a solution to the on-line combination of HILIC and RPC achieving better separation of 17 constituents in P. ginseng leaves. 179 Moreover, post-column ( 1 D-HILIC) dilution by the aqueous phase ( e.g. 0.1% formic acid) is also feasible for solving the solvent incompatibility in multiple heart-cutting 2D-LC (MHC-2D LC) for the quantitative determination of 24 saponins from P. notoginseng flowers and leaves.…”

Recent Developments in Two-Dimensional Liquid Chromatography: Fundamental Improvements for Practical Applications

“…Recent examples are evaporative membrane modulation and longitudinal on-column thermal modulation . A completely different approach that was recently proposed is fractionized stacking and sampling, where the 1 D effluent is split in a number of segments prior to introduction to the second-dimension column . The last approach that we will discuss is vacuum-evaporation modulation (VEM), which was developed by the group of Guan .…”

Development of an At-Column Dilution Modulator for Flexible and Precise Control of Dilution Factors to Overcome Mobile Phase Incompatibility in Comprehensive Two-Dimensional Liquid Chromatography

“…In order to resolve the mobile phase incompatibility, many valuable strategies have been proposed . In these reported methods, the valve-based modulation method strategy is the most common, including interface with double trapping column, ,− vacuum-assisted solvent evaporation interface, , loop interface with post first-column diluting and splitting, , solvent switch modulation, − and online dilution interface with bypass, ,− etc.…”