Method for evaluation of ionic interactions in liquid chromatography

Kadlecová, Zuzana; Kalíková, Květa; Folprechtová, Denisa; Tesařová, Eva; Gilár, Martin

doi:10.1016/j.chroma.2020.461301

Cited by 20 publications

(13 citation statements)

References 53 publications

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“…The increasing retention factor of AMP between pH 2.5 and 5.5 is attributed to its increasing negative charge. The decrease in its retention factor above pH 5.5 is due to the decreasing positive charge of the stationary phase [26].…”

Section: Resultsmentioning

confidence: 99%

“…BEH C 18 AX columns give retention factors for neutral compounds that are very similar to those obtained using HSS T3 columns, which contain an intermediate-coverage C 18 bonded phase based on 100 Å silica particles. The BEH C 18 AX stationary phase contains both C 18 and tertiary alkylamine groups, the latter creating a positive surface charge below approximately pH 9 [26]. CSH C 18 is similar to BEH C 18 AX in having both C 18 and anion-exchange groups.…”

Section: Chemical and Physical Properties Of The Stationary Phasesmentioning

confidence: 99%

“…CSH C 18 is similar to BEH C 18 AX in having both C 18 and anion-exchange groups. However, the anion-exchange groups in CSH C 18 contain pyridine functionalities, which are positively charged only below approximately pH 5-6 [26,27].…”

Section: Chemical and Physical Properties Of The Stationary Phasesmentioning

confidence: 99%

“…The retention trends for the charged analytes may be explained by differences in the surface charge of the different stationary phases. The BEH C 18 AX and CSH C 18 stationary phases have a positive surface charge at pH 3 due to the presence of the anion-exchange groups, with BEH C 18 AX having the greater positive charge [26]. The positive surface charge results in increased retention of anions, such as AMP, and decreased retention of cations, such as nicotinamide and procainamide.…”

Section: Retention and Selectivitymentioning

confidence: 99%

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Characterization of a highly stable mixed‐mode reversed‐phase/weak anion‐exchange stationary phase based on hybrid organic/inorganic particles

Walter

Alden

Field

et al. 2021

J of Separation Science

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We have characterized Atlantis ethylene‐bridged hybrid C18 anion‐exchange, a mixed‐mode reversed‐phase/weak anion‐exchange stationary phase designed to give greater retention for anions (e.g., ionized acids) compared to conventional reversed‐phase materials. The retention and selectivity of this stationary phase were compared to that of three benchmark materials, using a mixture of six polar compounds that includes an acid, two bases, and three neutrals. The compatibility of the ethylene‐bridged hybrid C18 anion‐exchange material with 100% aqueous mobile phases was also evaluated. We investigated the batch‐to‐batch reproducibility of the ethylene‐bridged hybrid C18 anion‐exchange stationary phase for 27 batches across three different particle sizes (1.7, 2.5, and 5 μm) and found it to be comparable to that of one of the most reproducible C18 stationary phases. We also characterized the acid and base stability of the ethylene‐bridged hybrid C18 anion‐exchange stationary phase and the results show it to be usable over a wide pH range, from 2 to 10. The extended upper pH limit relative to silica‐based reversed‐phase/weak anion‐exchange materials is enabled by the use of ethylene‐bridged hybrid organic/inorganic particles. The improved base stability allows Atlantis ethylene‐bridged hybrid C18 anion‐exchange to be used with a wider range of mobile phase pH values, opening up a greater range of selectivity options.

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Section: Resultsmentioning

confidence: 99%

Section: Chemical and Physical Properties Of The Stationary Phasesmentioning

confidence: 99%

Section: Chemical and Physical Properties Of The Stationary Phasesmentioning

confidence: 99%

Section: Retention and Selectivitymentioning

confidence: 99%

See 2 more Smart Citations

Characterization of a highly stable mixed‐mode reversed‐phase/weak anion‐exchange stationary phase based on hybrid organic/inorganic particles

Walter

Alden

Field

et al. 2021

J of Separation Science

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show abstract

“…Anionic retention diminishes above pH 7, before the expected pK a value of primary alkylamine surface modifier (amine pK a ∼ 10.6). This can be related to deprotonation of resid-ual silanols (about pH 7) on the sorbent surface leading to a diminished surface charge [12]. Ethylene-bridged C18 anion-exchange BEH C18 AX column designed to give greater retention for anions was compared to conventional reversed-phase material.…”

Section: Introductionmentioning

confidence: 99%

Separation of pharmaceutically active compounds by multimodal chromatography with ultraviolet detection

Grybinik

Douša²,

Bosáková

2021

Separation Science Plus

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This research focused on pharmaceutically active ingredients analyzed by mixedmode liquid chromatography. For this purpose, 16 analytes were chosen with acidic, basic, or neutral properties that were analyzed under different conditions. These analytes play an important role in the pharmaceutical industry and improved separation will make drug control more efficient. Mixed-mode chromatography is becoming an increasingly popular method for the analysis of diverse compounds due to the process being based on the combination of two or more interaction modes. The use of the mixed-mode stationary phase can be especially beneficial for the development of new drugs which may have specific physical and chemical properties. Data obtained from measurements on three different mixed-mode columns (WAX-1, WCX-1, and HILIC-1) were used to construct the plots illustrating the relationship between the retention factors of the analytes and organic modifier content, buffer concentration, and buffer pH. As a result of the known chemical structures of the analyzed molecules and analysis of these plots, possible interaction mechanisms in various chromatographic systems were proposed. Conclusions enabled suggestions for the optimization of chromatographic conditions to be made as well as the improved selection of the stationary phase for different types of analytes.

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Contribution of ionic interactions to stationary phase selectivity in hydrophilic interaction chromatography

Gilár

Berthelette

Walter

2022

J of Separation Science

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We compared the separation selectivities of 19 different hydrophilic interaction chromatography columns. The stationary phases included underivatized silica and hybrid particles, cyano-bonded silica, materials with neutral ligands such as amide, diol, pentahydroxy, and urea, zwitterionic sorbents, and mixed-mode materials with amine functionalities. A set of 77 small molecules was used to evaluate the columns. We visualized the retention behavior of the different columns using retention time correlation plots. The analytes were classified as cations, anions, or neutral based on their estimated charge under the separation conditions. This involved adjusting the dissociation constants of the analytes for the acetonitrile content of the mobile phase and experimentally determining the pH of the mobile phase containing 70% acetonitrile. The retention correlation plots show that the selectivity differences strongly depended on ionic interactions. Comparisons of the neutral stationary phases (e.g., diol vs. amide) showed more similar selectivity than did comparisons of neutral columns versus columns with cation or anion exchange activity (bare silica or amine columns, respectively). The zwitterionic columns did not behave as perfectly neutral. The correlation plots indicated that they exhibited either cation or anion exchange activity, although to a lesser degree than the silica and amine-containing stationary phases.

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Method for evaluation of ionic interactions in liquid chromatography

Cited by 20 publications

References 53 publications

Characterization of a highly stable mixed‐mode reversed‐phase/weak anion‐exchange stationary phase based on hybrid organic/inorganic particles

Characterization of a highly stable mixed‐mode reversed‐phase/weak anion‐exchange stationary phase based on hybrid organic/inorganic particles

Separation of pharmaceutically active compounds by multimodal chromatography with ultraviolet detection

Contribution of ionic interactions to stationary phase selectivity in hydrophilic interaction chromatography

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