Determination of diffusion coefficients and separation numbers in micellar electrokinetic chromatography

Muijselaar, Pim G.; Straten, Marion A. van; Claessens, H.A.; Cramers, C.A.M.G.

doi:10.1016/s0021-9673(96)00988-0

Cited by 16 publications

(14 citation statements)

References 21 publications

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“…Values of the interaction constants of the alkylphenyl ketones were calculated from the data within Muijselaar et al [58] À9 m 2 /Vs was used [59], while for separations in fused-silica capillaries the EOF was calculated from in situ data (model 1). The simulation time was 10 min with 1901 data points saved with each simulation requiring 20 h of computation time.…”

Section: Computer Simulationsmentioning

confidence: 99%

“…A series of alkylphenyl ketones were selected as model analytes due to the fact that they are commonly used to characterise additives in EKC. As such, it was possible to find theoretical data for the migration of these compounds from the literature, which could be used to estimate the interaction constants, K 3 , for each of the analytes [58]. In estimating these constants, the entire concentration of SDS was considered as an additive.…”

Section: Agreement With Experimental Datamentioning

confidence: 99%

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High‐resolution computer simulations of EKC

2009

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The electrophoresis simulation software, GENTRANS, has been modified to include the interaction of analytes with an electrolyte additive to allow the simulation of liquid-phase EKC separations. The modifications account for interaction of weak and strong acid and base analytes with a single weak or strong acid or base background electrolyte additive and can be used to simulate a range of EKC separations with both charged and neutral additives. Simulations of separations of alkylphenyl ketones under real experimental conditions were performed using mobility and interaction constant data obtained from the literature and agreed well with experimental separations. Migration times in fused-silica capillaries and linear polyacrylamide-coated capillaries were within 7% of the experimental values, while peak widths were always narrower than the experimental values, but were still within 50% of those obtained by experiment. Simulations of sweeping were also performed; although migration time agreement was not as good as for simple EKC separations, peak widths were in good agreement, being within 1-50% of the experimental values. All simulations for comparison with experimental data were performed under real experimental conditions using a 47 cm capillary and a voltage of 20 kV and represent the first quantitative attempt at simulating EKC separations with and without sweeping.

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Section: Computer Simulationsmentioning

confidence: 99%

Section: Agreement With Experimental Datamentioning

confidence: 99%

High‐resolution computer simulations of EKC

2009

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“…As in MEKC the efficiency is not independent of k, Kolb et al [52] suggested to calculate the overall peak capacity in MEKC from the sum of separation numbers (SNs) within a given z range. The SN of a separation electrolyte is defined as the number of component peaks that can be placed between the peaks of two consecutive homologous standards with z and z 1 1 carbon Table 2. chain atoms, each peak pair separated by a resolution of 1.177 [53].…”

Section: Acnmentioning

confidence: 99%

Separation of very hydrophobic analytes by micellar electrokinetic chromatography. III. Characterization and optimization of the composition of the separation electrolyte using carbon number equivalents

2008

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Four coefficients are suggested to characterize the separation properties of separation electrolytes in MEKC. These coefficients are the electrophoretic mobility of the pseudostationary phase (PSP), the electroosmotic mobility, and two parameters which can be obtained via the Martin equation using the retention data of the members of a suitable homologous series. These four coefficients are used for the characterization of separation electrolytes applicable to the separation of very hydrophobic analytes (log P(OW) = 3-4) with SDS as PSP and to quantitatively describe the influence of the buffer additives ACN and urea for the fine-tuning of retention factors and the additive calcium chloride for the fine-tuning of the width of the migration time window. Together with carbon number equivalents (N*(C)) as analyte descriptors the suggested coefficients provide a tool for the fast optimization of the composition of the separation electrolyte. The proposed method optimization scheme is applied to the separation of ingredients of essential oils. Predicted resolutions are compared to experimental results.

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“…It is, however, important to note that the requirement for Equation (1.17), constant plate numbers independent of the retention factor, is not fulfilled in practice. Some authors have therefore preferred to use the separation number SN instead of the peak capacity [27,28]. The separation number is defined as the number of component peaks that can be placed between the peaks of two consecutive homologous standards (e.g.…”

Section: Peak Capacitymentioning

confidence: 99%