Retention indices in micellar electrokinetic chromatography

Muijselaar, Pim G.

doi:10.1016/s0021-9673(97)00341-5

Cited by 19 publications

(13 citation statements)

References 27 publications

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“…The same congeneric behavior was observed for retention indices [34,45,46]. This congeneric behavior is induced by the differences in the type of interaction between the solute and the two "solvents" involved.…”

Section: Relationship To Octanol-water Partitioning Coefficientssupporting

confidence: 64%

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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Section: Relationship To Octanol-water Partitioning Coefficientssupporting

confidence: 64%

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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“…Well-known and frequently referred testing procedures were reported by Engelhardt [38,39], Tanaka [40], Jandera [41], Claessens [42], and Szepesy [43]. Muijselaar et al [7,32] invented the retention indices in MEKC to estimate the influence of different surfactant systems on selectivity and retention.…”

Section: Introductionmentioning

confidence: 99%

Micellar proportion: A parameter to compare the hydrophobicity of the pseudostationary phases or that of the analytes in micellar electrokinetic chromatography

et al. 2005

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Micellar proportion, t(prop,mic) = t(mic)/t(m), a quantity expressing how much time is spent by the analyte in the micellar phase related to its whole migration time (t(m)) has been introduced by utilizing the micellar phase residence time (t(mic)). The t(prop,mic) values have been determined for analytes of different chemical structures (alkyl benzene and alkyl phenone homologous series, alcohols, strongly hydrophobic peptides) studied by micellar elektrokinetic chromatography (MEKC) using various cationic and anionic pseudostationary phases. A good linear correlation was obtained between t(prop,mic) and the calculated hydrophobicity (CLOGP) of the analytes for all pseudostationary phases (CLOGP = A.logt(prop,mic) + B). Considering a given pseudostationary phase, t(prop,mic) as a relative quantity is a suitable parameter to characterize and compare experimentally the behavior of the various analytes in MEKC. Applying a set of probe molecules with known hydrophobicity, the CLOGP(50) value (showing the value of hydrophobicity of a virtual molecule spending exactly 50% of its migration time in the pseudostationary phase) has been calculated for each pseudostationary phase applied here. This experimentally determinable numerical value (characterizing the pseudostationary phase) can be utilized to compare the hydrophobicity and hence retention ability of the pseudostationary phases. The t(prop,mic) value was found to be applicable to compare the methylene selectivity of the different pseudostationary phases as well: logt(prop,mic) = A.Z + B, where Z is the number of carbon atoms of the alkyl chain in the alkyl benzene homologous series.

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“…Therefore, chromatographic systems including MEKC have been gaining an ever-increasing importance in the characterisation of hydrophobicity of molecules in the last years [1,[6][7][8][9][10]. The direct connection between data obtained by chromatographic processes and the biological properties may be a promising field of work [11][12][13][14].…”

Section: Introductionmentioning

confidence: 99%

Characterisation of mixed lithium dodecyl sulphate/lithium perfluorooctanesulphonate pseudo‐stationary phases in MEKC

et al. 2009

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Lipophilicity and methylene selectivity of mixed pseudo-stationary phases (PSPs) (containing lithium dodecyl sulphate (LDS) and lithium perfluorooctanesulphonate (LiPFOS) in different molar ratios) applied in MEKC have been investigated. Micellar proportion (t(prop,mic), a quantity expressing that how much time is spent by the analyte in the micellar phase related to its whole migration time), CLOGP(50) value (showing the value of hydrophobicity of a molecule spending exactly 50% of its migration time in the PSP) and methylene selectivity have been determined for different LDS/LiPFOS mixed phases. Values of the above-mentioned parameters have been determined for analytes with different chemical structures (alkylbenzene and alkylphenone homologous series, alcohols). Good linear correlation was obtained between either the micellar proportion, CLOGP(50), or methylene selectivity and the phase composition for the mixed phases. Lipophilicity and methylene selectivity of the mixed LDS/LiPFOS PSPs can be calculated and can continuously be changed by mixing the two single phases (LDS and LiPFOS) in the appropriate (and calculable) portion.

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Retention indices in micellar electrokinetic chromatography

Cited by 19 publications

References 27 publications

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

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

Micellar proportion: A parameter to compare the hydrophobicity of the pseudostationary phases or that of the analytes in micellar electrokinetic chromatography

Characterisation of mixed lithium dodecyl sulphate/lithium perfluorooctanesulphonate pseudo‐stationary phases in MEKC

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