Effect of Temperature on the Orientation of Bonded Hydrocarbon Phases in Totally Aqueous Liquid Chromatographic Systems

Gilpin, R. K.; Squires, J.

doi:10.1093/chromsci/19.4.195

Cited by 107 publications

(38 citation statements)

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“…7a) and their respective idealized drawings (Fig. 7b) follows the "bristle brush", "haystack", "ink bottle", and other models presented by Halasz and Sebestian [21], Hemetsberger et al [22], Lochmuller and Wilder [27] and others [23][24][25]. These experiments reiterate the solution NMR experiments done on alkyl-chain derivatized HPLC silica particles packed within an NMR tube [9,12,[15][16][17][18]26,28,29,31,32], albeit, with the NMR Wool Tube experiments, more solvent mixtures were examined.…”

Section: The Spectral Characteristics Of the Bonded Phase In The Presmentioning

confidence: 75%

NMR Wool Tube: a novel method for NMR solution analysis of derivatized glass surfaces

Cholewa

2004

Journal of Chromatography A

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Section: The Spectral Characteristics Of the Bonded Phase In The Presmentioning

confidence: 75%

NMR Wool Tube: a novel method for NMR solution analysis of derivatized glass surfaces

Cholewa

2004

Journal of Chromatography A

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“…incomplete solvation, stronger folding and collapsing of the alkyl chains [69,70,[85][86][87]. Similar conformational changes are not probable on calixarene phases because of their high degree of internal order.…”

Section: Properties Of the Single Interactionsmentioning

confidence: 99%

Characterization of calixarene‐bonded stationary phases

Schneider

Menyes²,

Jira

2010

J of Separation Science

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Calixarene-bonded stationary phases received growing interest in HPLC as stationary phases with special retention characteristics and selectivity. The commercially available unsubstituted and p-tert-butyl-substituted Caltrex(®) columns have been intensively studied and characterized in our workgroup. They can be used as reversed phases, yet they support additional interactions. Especially, their steric, polar and ionic properties differ from conventional alkyl-bonded phases. However, also the hydrophobic interaction shows differences since adsorption and partition interactions on or in a bonded layer of calixarenes are not similar to those of alkyl-bonded layers. The relative strength of the hydrophobic properties of the stationary phases has been found depending on the methanol concentration of the mobile phase. Generally, the dependencies of their interaction strengths on mobile-phase conditions, e.g. the change of the intensity of the hydrogen-bonding abilities with decreasing methanol content, are not similar from phase to phase either. This probably gives calixarene-bonded stationary phases enhanced suitability for analyses at extreme compositions of the mobile phase. An overview about the synthesis, retention and selectivity properties of Caltrex(®) columns is given here.

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“…resolvation of achiral column surfaces [21 -23]. In the chromatographic studies [21,22], only three heating curves were recorded (no cooling curve was recorded). The columns were cooled between each heating curve.…”

Section: Column History and Temperature-induced Hysteresis In Heatingmentioning

confidence: 99%

Column temperature programming in enantioseparation of dihydropyrimidinone compounds using derivatized cellulose and amylose chiral stationary phases

Wang¹,

Yeung²,

Han³

et al. 2008

J of Separation Science

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We report the application of column temperature programs as a tool to examine unusual temperature-induced behaviors of polysaccharide chiral stationary phases (CSPs). Using dihydropyrimidinone (DHP) compounds as probes we observed the heating (10-50 degrees C) and cooling (50-10 degrees C) van't Hoff plots of retention factors and/or selectivities of DHP compounds were not superimposable on AD, IA, and AS-H columns solvated with ethanol (EtOH)/n-hexane (n-Hex) mobile phases. The plots were not superimposable on AD, IB, and AS-H columns solvated with 2-propanol (2-PrOH)/n-Hex mobile phases. The thermally induced path-dependant behaviors were caused by slow equilibration as evidenced by the disappearance of the hysteresis in the second heating to cooling cycle and in a cooling to heating cycle. From the step-temperature program (10-50-10 degrees C), only EtOH solvated AD and AS-H phases showed the change of retention factors and/or selectivities with time while only 2-PrOH solvated AS-H phase showed similar behaviors.

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Effect of Temperature on the Orientation of Bonded Hydrocarbon Phases in Totally Aqueous Liquid Chromatographic Systems

Cited by 107 publications

References 0 publications

NMR Wool Tube: a novel method for NMR solution analysis of derivatized glass surfaces

NMR Wool Tube: a novel method for NMR solution analysis of derivatized glass surfaces

Characterization of calixarene‐bonded stationary phases

Column temperature programming in enantioseparation of dihydropyrimidinone compounds using derivatized cellulose and amylose chiral stationary phases

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