Mobile and stationary phases for SFC: Effects of using modifiers

Janssen, Hans Gerd; Schoenmakers, Peter J.; Cramers, C.A.M.G.

doi:10.1007/bf01245520

Cited by 10 publications

(2 citation statements)

References 17 publications

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“…Here, D is the distribution coefficient, c s and c m are the concentrations of a solute (mg mL −1 ) in the stationary and mobile phases, and β is the ratio of stationary to mobile phase volumes [19].…”

Section: Model Developmentmentioning

confidence: 99%

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

et al. 2021

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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.

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Section: Model Developmentmentioning

confidence: 99%

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

et al. 2021

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“…They confirmed that the introduction of low concentrations of modifiers into C02 affects retention of solutes by deactivating the residual silanol groups on the stationary phase. In a later paper, they evaluated and ranked polarity, density, deactivation, solvation, and swelling effects (94). They also evaluated methods of estimating critical properties and densities of mixed fluids.…”

Section: Mobile Phasesmentioning

confidence: 99%

Supercritical fluid chromatography and extraction

Chester¹,

Pinkston²,

Raynie³

1992

Anal. Chem.

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Retention and peak shape of acidic substances in capillary supercritical fluid chromatography with binary and ternary mobile phases

Karlsson

Buttler

Mathiasson

1992

J Microcolumn Separations

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Abstract. Acidic model compounds were chromatographed on a cyanopropyl capillary column using binary and ternary mobile phases with supercritical carbon dioxide as the primary mobile phase component. When a binary mobile phase was used, large amounts (> 15 W ) of methanol in carbon dioxide were needed to elute the most polar analytes.Formic and citric acid were tested as modifier additives. The addition of formic acid to the eluent resulted in virtually no positive effects on the chromatographic behavior of the acidic substances. Addition of small amounts of citric acid to the modifier did, on the other hand, significantly improve peak shapes of all acidic compounds tested. Retention could then be adjusted by changing the concentration ratio between carbon dioxide and the methanol-citric acid solution. The effect of the ternary citric acid additive is probably caused by deactivation of stationary phase active sites and possibly also facilitation of solute mass transfer across the boundary between the chromatographic phases. Finally, methanol could be replaced by less toxic ethanol as a modifier in binary and ternary mobile phases, without noticeable effects on the chromatographic behavior.

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Mobile and stationary phases for SFC: Effects of using modifiers

Cited by 10 publications

References 17 publications

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

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

Supercritical fluid chromatography and extraction

Retention and peak shape of acidic substances in capillary supercritical fluid chromatography with binary and ternary mobile phases

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