Organic polymer monolithic columns with incorporated bare and cyano-modified fumed silica nanoparticles for use in hydrophilic interaction liquid chromatography

Nisansala Ganewatta,Ziad El Rassi

doi:10.1186/s40543-020-00239-1

Abstract

This research article presents the preparation and characterization of monolithic columns with incorporated bare fumed silica nanoparticles (FSNPs) and cyano-modified FNSPs (CN-FSNPs) and their subsequent use in hydrophilic interaction liquid chromatography (HILIC) of neutral, polar, and low molecular weight solutes. The monolithic support was based on the in situ polymerization of glyceryl monomethacrylate (GMM) and ethylene glycol dimethacrylate (EDMA) yielding the poly(GMM-co-EDMA) monolith for the incorporation of bare FNSPs and of CN-FSNPs. The poly(GMM-co-EDMA) functioned as a “true support” for bare FSNPs and CN-FSNPs “stationary phases” as manifested by bare FSNPs and CN-FSNPs being the major contributors to solute retention and column selectivity. Overall, the prepared bare FSNPs and CN-FSNPs stationary phases proved useful in HILIC of small polar solutes including dimethylformamide, formamide, thiourea, nucleobases, nucleosides, organic acids, food additives, vitamins, and biological amines.

Highlights

Hydrophilic interaction liquid chromatography (HILI C) has gained an increasing attention during the last decade as a promising method for the separation of polar compounds where the use of both reversed phase and normal phase chromatography may be unsuccessful (Jandera, 2011; Jiang et al, 2011)
This paper describes monolithic stationary phases with incorporated fumed silica nanoparticles (FSNPs) which were pre-column surface modified with a polar organosilane
To the best of our knowledge, this study demonstrated for the first time, the use of pre-column modified FSNPs incorporated into a polymer monolithic stationary phase to enhance the separation performance of polar molecules under hydrophilic interaction liquid chromatography (HILIC) conditions

Summary

Introduction

Hydrophilic interaction liquid chromatography (HILI C) has gained an increasing attention during the last decade as a promising method for the separation of polar compounds where the use of both reversed phase and normal phase chromatography may be unsuccessful (Jandera, 2011; Jiang et al, 2011). In preparing the polymerization solution which had a final weight of 2.88 g, GMM at 29.59 wt%, EDMA at 13.31 wt%, and CN-FSNPs at varying wt% in the 0.35–2.77 wt% range were added to the binary porogenic solvent mixture consisting of cyclohexanol at 29.01–30.23 wt% and 1-dodecanol at 25.03–26.25 wt% in order to complete to a total of 100 wt% with that of the wt% of CN-FSNPs. AIBN 0.27 wt% was added, and the resulting polymerization solution was vortexed for 2 min followed by low power sonication for 20 min before introducing it into the 15-cm long stainlesssteel column which was assembled and used as described in the preparation of bare FSNPs incorporated monolithic columns.

Results

Conclusion