Reducing Dilution and Analysis Time in Online Comprehensive Two-Dimensional Liquid Chromatography by Active...

Area of Science:

• Analytical Chemistry
• Chromatography Science

Background:

• Comprehensive two-dimensional liquid chromatography (LC × LC) provides high peak capacity and selectivity beyond one-dimensional LC (1D-LC).
• LC × LC often suffers from reduced sensitivity due to dilution and long analysis times, limiting its practical applications.

Purpose of the Study:

• To develop and demonstrate an active-modulation approach for concentrating fractions between chromatographic dimensions in LC × LC.
• To mitigate the inherent downsides of dilution and extended run times in LC × LC systems.

Main Methods:

• Implementation of a modified LC × LC system incorporating a dilution flow and a trap-column based modulation unit for active concentration.
• Application of the developed system for separating tristyrylphenol ethoxylate phosphate surfactants using hydrophilic interaction and reversed-phase liquid chromatography.

Main Results:

• The modified LC × LC system achieved a 5-fold reduction in analysis time compared to traditional HPLC and halved the time compared to UHPLC-based LC × LC.
• Significant reductions in dilution (up to 10x) and solvent consumption (up to 10x) were observed.
• Comparable separation efficiency was maintained despite the reduced analysis time and dilution.

Conclusions:

• Active modulation with trap columns is an effective strategy to overcome sensitivity and time limitations in LC × LC.
• This approach enhances the practicality and efficiency of LC × LC for analyzing complex mixtures, such as surfactant compounds.