Characterization of calixarene- and resorcinarene-bonded stationary phases

Sokoließ, Torsten; Schönherr, Janet; Menyes, Ulf; Roth, U.; Jira, Thomas

doi:10.1016/j.chroma.2003.09.014

Cited by 38 publications

(35 citation statements)

References 27 publications

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“…Considering H for Caltrex ® A and B columns of the same ring size, one finds that the values are generally higher for the B-type columns. Thus the results of the work of Sokoließ et al 6 can be confirmed. Higher hydrophobic retention capacity had been found for tert-butylcalix [4]arene-bonded columns than for calix [4]arenebonded columns and the difference was related to additional interactions of the tert-butyl-substituent and the deeper cavity.…”

Section: Hydrophobicitysupporting

confidence: 80%

“…The rigid triphenylene is more retained on more rigid alkyl-bonded and calixarene-bonded columns, whereas on flexible tertbutylcalixarene-bonded phases o-terphenyl is more retained. For the calix [6]-and calix [8]arenes this even leads to higher values of Sf for the Caltrex ® B columns compared to Caltrex ® A columns at pH 7.…”

Section: Steric Selectivitymentioning

confidence: 99%

“…2c -f). On calix [6]arene phases the flexible steric influence is even larger than the hydrophobic. Furthermore differences are obvious between derivatized and non-derivatized calixarenes.…”

Section: Comparisons Between Different Parametersmentioning

confidence: 99%

“…Additionally to the well known interactions of alkyl-bonded silicas, they can give rise to retention by forming complexes [2][3][4][5][6][7][8][9][10] and by providing p-p-interactions 3,7,11,12 or p-electron-transfer. [7][8][9][10][11][12] For that reason, calixarene-bonded phases exhibit special selectivities.…”

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confidence: 99%

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Selectivity of Calixarene-bonded Silica-phases in HPLC: Description of Special Characteristics with a Multiple Term Linear Equation at Two Different pH-Values

2008

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Calixarenes are supramolecules consisting of phenol units linked via methylene bridges. Covalently bonded to a silica gel, they act as a reversed-phase. Their application as a stationary phase in HPLC has been recently reviewed. 1Additionally to the well known interactions of alkyl-bonded silicas, they can give rise to retention by forming complexes [2][3][4][5][6][7][8][9][10] and by providing p-p-interactions 3,7,11,12 or p-electron-transfer. 7-12For that reason, calixarene-bonded phases exhibit special selectivities. It is obvious that differences of selectivities can be distinct between different kinds of calixarene-bonded phases and especially between calixarene-bonded phases and common C18-phases. In order to select suitable columns for new separation problems, it would be beneficial to numerically describe the retention characteristics and the selectivity of each column. Numerous works have been done in that field and mathematical models relating the retention factor to properties of the column, the solute and the mobile phase were developed. [13][14][15][16][17][18][19][20] The retention has been related to physicochemical parameters or, in more empiric ways, to parameters derived from retention data.The retention and selectivity characteristics of novel calixarene-bonded HPLC-phases are described here. Therefore a multiple term equation has been used. The mechanisms of retention are estimated with its single parameters. Theory Mathematical modelsA linear equation describing solute retention was introduced by Snyder:Here the retention of a solute ln k¢ is defined by its retention in pure water, a solute specific value S and the volume fraction of organic modifier f. Yet the equations applicability is limited to a range of 0.2 -0.8f. Equations valid over the whole range of mobile phase composition were described by Schoenmakers et al. 14,15 and by Bosch, Bou and Rosés. 16 Schoenmakers quadratic equation uses factors based on Hildebrands solubility parameter. 21 The factors can be calculated from physical parameters.The model of Rosés et al. is based on the Dimroth Reichardt polarity parameter ET(30). 22 This parameter had been related to log k¢ by Johnson et al. 17 and has been found to give better linear relations to log k¢ than the volume fraction of methanol. Under the assumption that stationary phase polarity is independent of mobile phase composition, Rosés model predicts retention factors by use of two variables. This leads to a simple equation which can be handled easily. Pappa-Louisi et al.23 studied various two-and three-parameter-models concerning their applicability to predict ln k¢. The best predictions could be given by a three-parameter-model, while the two-parametermodels gave comparatively poor results. They pointed out that generally the largest errors occur for predicting retention times of late eluting substances at low modifier concentrations and that predictions deteriorate if the observed modifier range expands.However, although such "compact" systems include only a small number of p...

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Section: Hydrophobicitysupporting

confidence: 80%

Section: Steric Selectivitymentioning

confidence: 99%

Section: Comparisons Between Different Parametersmentioning

confidence: 99%

mentioning

confidence: 99%

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Selectivity of Calixarene-bonded Silica-phases in HPLC: Description of Special Characteristics with a Multiple Term Linear Equation at Two Different pH-Values

2008

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“…The family of calix [4]resorcinarenes has also been used for various functions such as additive for capillary electrophoresis, 10 liquid membrane, 11,12 extraction, 13 chemical sensing, 14,15 and HPLC stationary phase. 16,17 Nonetheless, there are still limited reports on the utilization of calix [4]resorcinarenes 18 as adsorbent for heavy metal cations. C-Methylcalix [4]resorcinarene (CMCR) is calix [4]resorcinarene having four benzene rings and eight hydroxyl groups (Fig.…”

Section: Introductionmentioning

confidence: 99%

Adsorption Characteristics of Pb(II) and Cr(III) onto C-Methylcalix[4]resorcinarene

Jumina¹,

Sarjono²,

Siswanta³

et al. 2011

Journal of the Korean Chemical Society

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has been conducted. CMCR was produced by one step synthesis from resorcinol, acetaldehyde, and HCl. Most parameters in batch system confirm that CMCR is a good adsorbent for Pb(II) and Cr(III). Cr(III) uptake was bigger than that of Pb(II), but Cr(III) adsorption rate was slower than Pb(II). The adsorption kinetic of Pb(II) and Cr(III) adsorptions in batch followed pseudo 2 nd order kinetics model, but the kinetic of Pb(II) adsorption in fixed bed column system followed first order model. Desorption studies to recover the adsorbed Pb(II) was performed sequentially with distilled water and HCl, and the results showed that the adsorption was dominated by chemisorption.

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Contrast in Electron‐Transfer Mediation between Graphene Oxide and Reduced Graphene Oxide

et al. 2012

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The properties of graphene oxide (GO) and DNA-stabilised reduced graphene-oxide (rGO) sheets as electron-transfer mediators in partially blocked electrodes are evaluated employing electrochemical impedance spectroscopy. Evidences obtained from UV/Vis, Raman and FTIR spectroscopies, as well as atomic force microscopy, confirm that the reduction of exfoliated GO single sheets by hydrazine yields partially reduced graphene oxide featuring a high defect density. Two-dimensional assemblies of GO and rGO were formed through electrostatic adsorption at Au electrodes, sequentially modified with 11-mercaptoundecanoic acid (MUA) and poly-diallyldimethylammonium chloride (PDADMAC). The MUA:PDADMAC generates a strong blocking layer to the electron-transfer reaction involving the ferri/ferrocyanide redox couple. This blocking behaviour is not significantly affected upon adsorption of GO. However, adsorption of a sub-monolayer of rGO decreases the charge-transfer resistance by more than two orders of magnitude. Analysis of cyclic voltammograms and impedance spectra suggests that electron transfer in rGO assemblies is mediated by occupied states located just below the redox Fermi energy of the probe. These findings are discussed in the context of on-going controversies regarding the electrochemical reactivity of sp(2)-carbon basal planes.

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Characterization of calixarene- and resorcinarene-bonded stationary phases

Cited by 38 publications

References 27 publications

Selectivity of Calixarene-bonded Silica-phases in HPLC: Description of Special Characteristics with a Multiple Term Linear Equation at Two Different pH-Values

Selectivity of Calixarene-bonded Silica-phases in HPLC: Description of Special Characteristics with a Multiple Term Linear Equation at Two Different pH-Values

Adsorption Characteristics of Pb(II) and Cr(III) onto C-Methylcalix[4]resorcinarene

Contrast in Electron‐Transfer Mediation between Graphene Oxide and Reduced Graphene Oxide

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