Evaluation of dead time calculation in liquid chromatography using a linearization procedure for homologous series

Tulder, P. J. M. van; Franke, J.P.; Zeeuw, Rokus A. de

doi:10.1002/jhrc.1240100407

Cited by 19 publications

(5 citation statements)

References 25 publications

(6 reference statements)

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“…Different measurement techniques of Vm have been proposed. 16,[42][43][44][45] In this work we used the technique of Wells and Clark: 43 injection of 4 × 10 -6 mol of NaNO3 with detection at 254 nm. Under our experimental conditions Vm was 1.38 ( 0.02 mL.…”

Section: Methodsmentioning

confidence: 99%

Correlations Between n-Octanol/Water Partition Coefficients and RP-HPLC Capacity Factors of 1,2-Dithiole-3-thiones and 1,2-Dithiol-3-ones

Boudeville¹,

Bona²,

Burgot³

1996

Journal of Pharmaceutical Sciences

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From the experimental n-octanol/water partition coefficients (log Poct) of 33 1,2-dithiole-3-thiones and 18 1,2-dithiol-3-ones and their respective log k, Collander-type relationships were established at various volume fractions of methanol in the mobile phase and on an ODS 2 stationary phase. Collander-type relationships were also established between log Poct and log K0 (capacity factor extrapolated to 0% of organic modifier). The correlations are good, and their parameters depend on the volume fraction of organic modifier, as expected. These relationships were used to evaluate the log Poct of seven very lipophilic dithiolethiones (3.7 < log P < 7.2). Extrapolated values were compared with calculated values from fragmental constants determined in a previous work and with those given by Rekker.

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Section: Methodsmentioning

confidence: 99%

Correlations Between n-Octanol/Water Partition Coefficients and RP-HPLC Capacity Factors of 1,2-Dithiole-3-thiones and 1,2-Dithiol-3-ones

Boudeville¹,

Bona²,

Burgot³

1996

Journal of Pharmaceutical Sciences

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“…Column hold-up times (t0) were determined using a linearization procedure for homologous series 36 (n-alcohols). Additionally the hold-up time of the chromatograph (t0C) was determined by injecting pure methanol without a column installed and this time has been subtracted from all retention data.…”

Section: Chromatographymentioning

confidence: 99%

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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“…The temperature was thermostated to 401C in all experiments and elution was carried out isocratically at a flow rate of 1 mL/min. Column hold-up times were determined using a linearization procedure for homologous series [98] (n-alcohols). Additionally, the hold-up time of the chromatograph was determined by injecting pure methanol without a column installed and has been subtracted from all retention data.…”

Section: Conditionsmentioning

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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Evaluation of dead time calculation in liquid chromatography using a linearization procedure for homologous series

Cited by 19 publications

References 25 publications

Correlations Between n-Octanol/Water Partition Coefficients and RP-HPLC Capacity Factors of 1,2-Dithiole-3-thiones and 1,2-Dithiol-3-ones

Correlations Between n-Octanol/Water Partition Coefficients and RP-HPLC Capacity Factors of 1,2-Dithiole-3-thiones and 1,2-Dithiol-3-ones

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

Characterization of calixarene‐bonded stationary phases

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