Electrokinetic chromatography with micellar solution and open-tubular capillary

Terabe, Shigeru; Otsuka, Koji; Ando, Teiichi

doi:10.1021/ac00281a014

Cited by 1,186 publications

(617 citation statements)

References 15 publications

Supporting

Mentioning

589

Contrasting

Unclassified

Order By: Relevance

“…At least three measurements were made for each experimental condition for which RSD values were calculated. The selectivity (a) is defined as k9 2 /k9 1 , where k9 1 and k9 2 are the retention factors of the first and second eluting enantiomers [34], respectively. Methanol was used as the neutral (t 0 ) marker and was measured from the time of injection to the first deviation from the baseline.…”

Section: Cementioning

confidence: 99%

A comparison of ionic liquids to molecular organic solvents as additives for chiral separations in micellar electrokinetic chromatography

Mwongela

Siminialayi

Fletcher

et al. 2007

J of Separation Science

View full text Add to dashboard Cite

A comparison of ionic liquids to molecular organic solvents as additives for chiral separations in micellar electrokinetic chromatographyIn this study, we report the effects of adding ionic liquids (ILs), as compared to adding conventional molecular organic solvents (MOSs), to aqueous buffer solutions containing molecular micelles in the separation of chiral analyte mixtures in micellar EKC (MEKC). The molecular micelle used in this study was polysodium oleyl-L-leucylvalinate (poly-L-SOLV). The ILs were 1-alkyl-3-methylimidazolium tetrafluoroborate, where the alkyl group was ethyl, butyl, hexyl, or octyl. These ILs were chosen due to their hydrophobicity, good solvating, and electrolyte properties. Thus, it was expected that these ILs would have favorable interactions with chiral analytes and not adversely affect the background current. Common CE buffers, mixed with a molecular micelle, and an IL or a MOS, were used for these chiral separations. The buffers containing an IL in the concentration range of 0.02 -0.1 v/v were found to support a reasonable current when an electric field strength of 500 V/cm was applied across the capillary. However, a current break down was observed for the buffers containing more than 60% v/v MOS on application of the above-mentioned electric field. The chiral resolution and selectivity of the analytes were dependent on the concentration and type of IL or MOS used.

show abstract

Section: Cementioning

confidence: 99%

A comparison of ionic liquids to molecular organic solvents as additives for chiral separations in micellar electrokinetic chromatography

Mwongela

Siminialayi

Fletcher

et al. 2007

J of Separation Science

View full text Add to dashboard Cite

show abstract

“…Since the diameter of the capillary is fixed, the injected amount of an analyte can be quantified by the comparatively occupied capillary length ( l inj ). The electrophoretic mobility of anions is in the same direction as the bulk flow, therefore it can be determined by Equation 12, (12) where V ep is the electrophoretic velocity of the analyte. At the very beginning of the injection process, the bulk flow is at the maximum V eo1 , which is produced when the entire capillary is filled with the separation buffer.…”

Section: Estimation Of Injected Sample Volumementioning

confidence: 99%

“…12 The most commonly used sweeping carriers are micelles of sodium dodecyl sulfate (SDS) 9 which is a good choice for sweeping neutral and cationic analytes. Other kinds of surfactants used for sweeping include cationic, 13 nonionic 14 and polymeric, 15 as well as mixed micelles.…”

mentioning

confidence: 99%

Unlimited-Volume Electrokinetic Stacking Injection in Sweeping Capillary Electrophoresis Using a Cationic Surfactant

et al. 2006

View full text Add to dashboard Cite

Sweeping is an effective and convenient way for online sample preconcentration in micellar electrokinetic chromatography (MEKC). The usual procedure includes a hydrodynamic injection step carried out by applying pressure to the sample vial followed by the subsequent sweeping and separation processes. The injected sample volume is limited by the dimensions of the capillary because a part of the capillary has to be left free of sample solution for the subsequent sweeping and separation steps. In addition, when a short capillary, such as 4-10 cm, is used for sweeping, the injected sample volume is small even if the entire capillary is filled with sample solution. In order to solve this problem, an electrokinetic stacking injection (EKSI) scheme was developed by using a cationic surfactant, dodecyltrimethylammonium bromide, for sweeping in capillary electrophoresis. An experimental model was proposed, and the entire process was theoretically analyzed. According to the theoretical discussion, the optimal conditions for two model analytes, 5-carboxyfluorescein (5-FAM) and sodium fluorescein (FL), were experimentally determined. The injected sample plug lengths for 5-FAM and FL under 20.1 kV for 60 min were experimentally estimated as 836 and 729 cm, corresponding to 28-and 24-fold the effective capillary length, respectively. The EKSI scheme resulted in increased detection factors for 5-FAM and FL of 4.5×10 3 and 4.0×10 3 using 60-minute injection relative to a traditional pressure injection.

show abstract

“…The capacity factor, k 0 of uncharged solutes was calculated from the observed migration times using the following equation [33,34]:…”

Section: Principles Of Affinity Capillary Electrophoresismentioning

confidence: 99%

Use of affinity capillary electrophoresis for characterizing pharmaceutical colloidal vehicle systems thermodynamically

Neubert¹,

Mrestani²

2001

Biopharm & Drug Disp

View full text Add to dashboard Cite

This review offers a detailed discussion of the interaction between pharmaceutical compounds and vehicles using the affinity capillary electrophoresis and the microemulsion electrokinetic chromatography. Partition coefficients of drugs were calculated between a micelle and an aqueous phases from the measurement of the migration time, provided the critical micelle concentration and the phase ratio are known. Thermodynamic quantities such as enthalpy and entropy changes of micellar solubilization were calculated from the temperature dependence of the partition coefficients. Partial specific volumes were measured using dynamic light scattering. The logarithm of the partition coefficients and the capacity factor in the micellar system were correlated with the logarithm of the n-octanol/water partition coefficients.

show abstract

Electrokinetic chromatography with micellar solution and open-tubular capillary

Cited by 1,186 publications

References 15 publications

A comparison of ionic liquids to molecular organic solvents as additives for chiral separations in micellar electrokinetic chromatography

A comparison of ionic liquids to molecular organic solvents as additives for chiral separations in micellar electrokinetic chromatography

Unlimited-Volume Electrokinetic Stacking Injection in Sweeping Capillary Electrophoresis Using a Cationic Surfactant

Use of affinity capillary electrophoresis for characterizing pharmaceutical colloidal vehicle systems thermodynamically

Contact Info

Product

Resources

About