Reproducibility of migration times and propagation of error in micellar electrokinetic chromatography

Vindevogel, Johan; Szücs, Roman; Sandra, Patrick

doi:10.1002/mcs.1220040506

Cited by 4 publications

(3 citation statements)

References 5 publications

(5 reference statements)

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“…Since solubilization, the interaction of solute with micelles, operates as a distribution process, the primary driving force is the hydrophobic interaction between the solutes and micelles [2,3]. Hence, retention data involve the information related to the interaction between the solute and the micelle, and in turn to the hydrophobicity of the analyte [4,5].…”

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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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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“…In line with data in Table 1 we observed that the repeatability of migration times in the three systems under consideration is broadly identical. This observation is further reinforced by the broadly identical repeatability of peak areas as in CE the observed peak areas are affected by the velocity of migration of the separated zones [ 22 , 23 ].…”

Section: Resultsmentioning

confidence: 87%

Advantages and Pitfalls of Capillary Electrophoresis of Pharmaceutical Compounds and Their Enantiomers in Complex Samples: Comparison of Hydrodynamically Opened and Closed Systems

Masár

Hradski

Schmid

et al. 2020

IJMS

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Several research disciplines require fast, reliable and highly automated determination of pharmaceutically active compounds and their enantiomers in complex biological matrices. To address some of the challenges of Capillary Electrophoresis (CE), such as low concentration sensitivity and performance degradation linked to the adsorption and interference of matrix components, CE in a hydrodynamically closed system was evaluated using the model compounds Pindolol and Propranolol. Some established validation parameters such as repeatability of injection efficiency, resolution and sensitivity were used to assess its performance, and it was found to be broadly identical to that of hydrodynamically opened systems. While some reduction in separation efficiency was observed, this was mainly due to dispersion caused by injection and it had no impact on the ability to resolve enantiomers of model compounds even when spiked into complex biological matrix such as blood serum. An approximately 18- to 23-fold increase in concentration sensitivity due to the employment of wide bore capillaries was observed. This brings the sensitivity of CE to a level similar to that of liquid chromatography techniques. In addition to this benefit and unlike in hydrodynamically opened systems, suppression of electroosmotic flow, which is essential for hydrodynamically closed systems practically eliminates the matrix effects that are linked to protein adsorption.

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“…These criteria can be satisfied by the use of MECC. Reproducibility of separations in MECC and CZE has been addressed by various researchers [12][13][14][15][16][17][18][19][20]. Some previous discussions of reproducibility have centered on the analysis of standards [14-151, Reagents.…”

Section: Introductionmentioning

confidence: 99%

Reproducibility of the determination of caffeine in coffee by micellar electrokinetic capillary chromatography

Burton

Powell

1994

J Microcolumn Separations

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Abstract. Samples of regular and decaffeinated varieties of green coffee beans, instant coffee, and "roast & grind" coffee have been examined by micellar electrokinetic capillary chromatography (MECC). The separation conditions affecting the reproducibility of the determination of caffeine in these samples are presented. Sodium dodecyl sulfate (SDS) and cetyltrimethylammonium chloride (CTAC) were employed to demonstrate the role of the surfactant system in reproducibility. The use of NaOH and HC1 was explored for column rinsing to enhance the stability of the electroosmotic flow. The levels of caffeine ranged from 3.95% (by weight) for regular coffee to 0.07% for decaffeinated coffee. The relative standard deviation (RSD) for the migration time of the peak corresponding to caffeine in coffee samples was 0.74 % . The RSDs for the peak areas and heights were 1.04 and 2.07%, respectively. The results of the quantitation of caffeine by MECC are compared to levels determined by high-performance liquid chromatography (HPLC).

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Reproducibility of migration times and propagation of error in micellar electrokinetic chromatography

Cited by 4 publications

References 5 publications

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

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

Advantages and Pitfalls of Capillary Electrophoresis of Pharmaceutical Compounds and Their Enantiomers in Complex Samples: Comparison of Hydrodynamically Opened and Closed Systems

Reproducibility of the determination of caffeine in coffee by micellar electrokinetic capillary chromatography

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