Development and Validation of Retention Models in Supercritical Fluid Chromatography for Impregnation Process Design

Miaotian Sun,Monika Johannsen,Zeynep Ülker,Zhixing Chen,Can Erkey,Pavel Gurikov,Sivaraman Deeptanshu

doi:10.3390/app11157106

Abstract

The retention factor is the key quantity for the thermodynamic analysis of the retention mechanism in chromatographic experiments. In this work, we measure retention factors for moderately polar solutes on four silica-based porous matrices as stationary phases by supercritical fluid chromatography. Elution of the solutes is only possible with binary mixtures of supercritical carbon dioxide (sc-CO2) and modifier (methanol) due to the low polarity of pure sc-CO2. The addition of modifiers makes the retention mechanism more complex and masks interactions between solute and stationary phase. In this work, we develop and validate several retention models that allow the obtaining of retention factors in modifier-free sc-CO2. Such models pave the way for quantifying adsorption interactions between polar solutes and non-swellable porous matrices in pure sc-CO2 based on retention data obtained in sc-CO2/modifier mixtures. The obtained information will thereby facilitate the understanding and design of impregnation processes, which are often performed in modifier-free conditions.

Highlights

Supercritical solvents and, in particular, supercritical carbon dioxide has gained world-wide attention in recent decades as a green processing media for the impregnation of porous matrices like wood, textile, monolithic and porous polymers with various solutes such as pharmaceutically active compounds, pesticides, or organometallic compounds, among others [1,2,3]
We mainly focus on the first mechanism and aim to quantify adsorption interactions between a given solute on a given matrix, which contributes to the rational development of such impregnation processes
This work reports on experimental retention factors for moderately polar solutes on four silica-based porous matrices used as stationary phases in packed-column supercritical fluid chromatography (SFC)

Summary

Introduction

Supercritical solvents and, in particular, supercritical carbon dioxide (sc-CO2 ) has gained world-wide attention in recent decades as a green processing media for the impregnation of porous matrices like wood, textile, monolithic and porous polymers with various solutes such as pharmaceutically active compounds, pesticides, or organometallic compounds, among others [1,2,3]. Two mechanisms play the major roles in the impregnation processes: adsorption of the solutes on the matrix surface and precipitation upon solvent evaporation [1]. We mainly focus on the first mechanism and aim to quantify adsorption interactions between a given solute on a given matrix, which contributes to the rational development of such impregnation processes

Objectives

Methods

Conclusion