Column selectivity in reversed-phase liquid chromatography: V. Higher metal content (type-A) alkyl-silica columns

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• 作者：Gilroy ; Jonathan J. ; Dolan ; John W. ; Carr ; P.W. ; Snyder ; Lloyd R.
• 关键词：Column seletivity ; Stationary phases ; LC ; Selectivity ; Alkyl-silica column ; Bonded-zirconia column
• 刊名：Journal of Chromatography A
• 出版年：2004
• 出版时间：February 13, 2004
• 年：2004
• 卷：1026
• 期：1-2
• 页码：77-89
• 全文大小：224 K

文摘

Retention measurements involving 16 test solutes have been carried out for 38 type-A alkyl-silica columns and three bonded-zirconia columns. These measurements have been analyzed in terms of a model previously developed for type-B columns, so as to yield values of five column selectivity parameters (H, S^*, A, B, C) for each type-A column. Overall differences in selectivity between type-A and -B columns can be related to the average values of H, S^*, etc. for each column type. Compared to type-B columns, type-A columns provide generally stronger retention for carboxylic acids, while solutes that are more hydrophobic or less bulky are more retained on type-B columns. Hydrogen-bond acceptors (e.g. aliphatic amides) and cations (e.g. protonated bases) are strongly retained on type-A versus type-B columns. Compared to type-B columns, bonded-zirconia columns show much increased retention of cations and reduced retention of hydrogen-bond acceptors. Because of relatively large differences in the selectivity of bonded-zirconia, type-A, and type-B columns, it will prove difficult to find columns of different type (e.g. a type-A and a type-B column) which have equivalent selectivity. Type-A columns also tend to be more different from each other (in terms of selectivity) than is the case for type-B columns. As a result, the replacement of a given type-A column by an “equivalent” type-A column also appears unlikely, except for samples that do not contain ionized compounds.