Effect of increasing concentration of ammonium acetate as an additive in supercritical fluid chromatography using CO2–methanol mobile phase
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- 作者：Amaury Cazenave-Gassiot ; Robert Boughtflower ; Jeffrey Caldwell ; Laure Hitzel ; Claire Holyoak ; Stephen Lane ; Paul Oakley ; Frank Pullen ; Stefan Richardson ; G. John Langley
- 关键词：Supercritical fluid chromatography ; Additives ; Ammonium acetate
- 刊名：Journal of Chromatography A
- 出版年：2009
- 出版时间：4 September 2009
- 年：2009
- 卷：1216
- 期：36
- 页码：6441-6450
- 全文大小：1288 K
文摘
The effects of increasing concentrations of ammonium acetate additive in supercritical fluid chromatography were studied on silica, 2-ethyl-pyridine and endcapped 2-ethyl-pyridine stationary phases. The study involved the addition of increasing concentrations of the ammonium acetate either in the mobile phase modifier (methanol) or in the sample solvent. The effects of ammonium acetate on retention and peak shape of the analytes were evaluated. Compounds that exhibited satisfactory chromatographic behaviour in the absence of the additive were virtually unaffected by its presence in the mobile phase or sample solvent. Nevertheless, compounds that exhibited late elution and strongly tailing peak shapes when pure methanol was used showed dramatically improved chromatographic behaviour in the presence of the additive. Shorter retention was observed not only when the modifier was introduced in the mobile phase but also when it was in the sample solvent.