2D-LC with solvent modulation to overcome the mobile phase incompatibility (Marie Pardon, MDCW 2023)

• 🎤 Presenter: Marie Pardon, Soraya Chapel, Peter de Witte, Deirdre Cabooter (KU Leuven, Leuven, Belgium)

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Abstract

Two-dimensional liquid chromatography (2D-LC) is becoming increasingly popular for the analysis of complex samples, which is partly due to the recent introduction of commercial 2D-LC systems. One of these systems employs active solvent modulation (ASM) to deal with the mobile phase incompatibility between highly orthogonal retention mechanisms, such as hydrophilic interaction liquid chromatography (HILIC) and reversed-phase LC (RPLC). However, clear recommendations or guidelines regarding the optimal use of ASM are not available.

Therefore, this study investigates possible configurations for the modulation of HILIC and RPLC using ASM in a selective comprehensive 2D-LC set-up (sHILIC x RPLC) to suggest guidelines for future users.

Using a representative sample, the filling percentage of the sample loops and their loading/unloading configuration, the duration of the ASM phase and the dilution factor (DF) are investigated and optimized. It is observed that maintaining the sample loop filling at maximum 25%, unloading it in backflush mode, and using a DF of 10 with the shortest possible ASM phase results in the best peak shapes, intensities and recoveries for early eluting peaks, while keeping the analysis time minimal.

Based on these results, some general recommendations are made: reduce the sample loop filling, the DF, and the duration of the ASM phase as much as possible, and operate in BF mode, in order to improve peak shapes and save analysis time.

These recommendations could also be applied to other 2D-LC modes, such as LC x LC and LC – LC, and other chromatographic combinations with mobile phase incompatibility issues.