• Analytical Science and Technology
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• v.10 no.5
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• pp.325-331
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• 1997

Among various CE separation methods, micellar electrokinetic capillary chromatography(MECC) method using sodium dodecylsulfate(SDS) provides rapid and accurate separation of organic explosive constituents with easy. The running buffer was composed with 2.5 mM borate and 25mM SDS(pH 8.5). Addition of 1M urea and 10% organic modifiers (acetonitrile, methanol and ethanol) improves the resolution of adjacent explosive constituents. When 15 explosive constituents were developed in MECC, most constituents were separated successively while RDX/TNB and DNN/DEP were not, and detection limits of separated compounds are in range of 1 to 4 ppm.

• KSBB Journal
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• v.20 no.3
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• pp.197-204
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• 2005

Lab-on-a-chip is a miniaturized analytical device in which all of the procedures for the analysis of molecules are carried out, such as pretreatment, reaction, separation, detection, etc. Lab-on-a-chip has increasing concern as a device not only for rapid detection of molecules but also for high throughput screening and point of care, because conventional laborious and time consuming analytical procedures can be substituted. Thus, a lot of microfabrication and analytical techniques for lab-on-a-chip have been developed with microstructures smaller than a few hundreds of micrometers. Separation of the molecules is one of the most important components of lab-on-a-chip, because effective separation method can simplify the design and can provide better sensitivity. The electrokinetic separation based on capillary electrophoresis is most widely employed technique in lab-on-a-chip for the control of fluids and the separation of molecules. In this article, bioseparation techniques and its applications realized in lab-on-a-chip are reviewed.

• Analytical Science and Technology
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• v.19 no.1
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• pp.50-57
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• 2006

Well known environmental wastes from dye industry were separated by the micellar electrokinetic capillary chromatography(MECC). These wastes include H-acid modifier and 2-naphthylamine-1,5-disulfonic acid, and are known to be the diazo components of the azo dye. The results of the separation were compared with the result obtained by the HPLC using ion-pairing mechnism. MECC method was also applied to separate a few direct dyes including Direct Blue 2, Direct Blue 6 and Direct Blue 15, and reactive dye such as Reactive Orange 4. Informations about the diazo components of any azo dye could be obtained by comparison of electropherogram of the reduction solution of given dye with those obtained from standard materials such as H-acid, J-acid, ${\gamma}$-acid, orthanilic acid, sulfanilic acid and 2-naphthylamine-1,5-disulfonic acid which are used as diazo components of the typical azo dyes. It has been concluded that MECC and HPLC with ion-pairing mechanism could be successfully applied for the analysis of unknown dyes and their diazo components.

• Proceedings of the IEEK Conference
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• 2001.10a
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• pp.459-465
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• 2001

The work was initiated to investigate the electrokinetic properties of a MF membrane using streaming potential measurement when oil emulsion was separated. The original and the surface modified PP membrane were examined by using flux and streaming potentials for the characterization of fouling phenomena of the PP membrane. The membrane surface was modified by a radiation grafting technique. The streaming potentials of the PP membranes were varied the charge distribution modifying by changing the pH, ionic strength, and concentrations the surfactants in oil emulsion. The shiftness to the more positive values of isoelectric point of the PP membrane was significant especially in the presence of surfactants or the surface modification.

• YAKHAK HOEJI
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• v.41 no.5
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• pp.539-546
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• 1997

Capillary electrophoresis (CE) is perceived as an attractive tool for the analysis of pharmaceuticals and biological materials because of their high separation efficiency, easy separation and low running cost. New concept of micellar electrokinetic capillary chromatography (MECC) expanded the application of CE to the separation of neutral molecules. Validation of CE as an analytical technique for quality control of pharmaceuticals should be confirmed by quantitative analysis and the peak confirmation. In this study, the quantitative analyses of various types of neutral, acidic and basic components (acetaminophen, caffeine, ascorbic acid, riboflavin, thiamine, chlorpheniramine, phenylpropanolamine, dl-methylephedrine and dextromethorphan) in complex cold medicines have been accomplished using CE. Combined methods of MECC using SDS and capillary zone electrophoresis lowering the pH of running buffer were adopted to determine the ingredients in capsule type or liquid formula complex medicines without particular sample pretreatment. The results indicate that CE is a promising technique for quality control analysis of pharmaceuticals as a validation method.

• Journal of Magnetics
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• v.16 no.4
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• pp.444-448
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• 2011

In the present study, we separated the marker particles from the suspending particle mixture solution using isotacho-electrophoresis technique, a novel quantitative ionic particle separation method, in the microchannel. A multiple stacking zone of the suspending particle was visualized with variations in electric field strength, pH value and concentration of the ionic solution. In particular, the electrophoretic mobility of ionic particle (fluorescein) was estimated based on the electrophoretic velocity value measured by the particle image velocimetry. As a result, isotacho-electrophoresis zones were clearly visualized as going downstream in the electric field. The particle migration velocity increased proportional to the applied voltage increase; it was also affected by the pH value variations in the ionic solution.

• Analytical Science and Technology
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• v.19 no.1
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• pp.31-38
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• 2006

Micellar electrokinetic capillary chromatography(MECC) and HPLC with ion-pairing mechanism were applied for the separation of the well known environmental wastes from dye industry. These compounds include H-acid, J-acid, ${\gamma}$-acid, orthanilic acid, sulfanilic acid and 2-naphthylamine-1,5-disulfonic acid, and are known to be the diazo components of the azo dye. MECC method was also applied to separate few acid dyes including Acid Orange 7, Acid Orange 5 and Acid Blue 92 and direct dye such as Direct Red 80. Informations about the diazo components of any azo dye could be obtained by comparison of electropherogram of the reduction solution of a given dye with those obtained from standard materials such as H-acid, J-acid, ${\gamma}$-acid, orthanilic acid, sulfanilic acid and 2-naphthylamine-1,5-disulfonic acid. It has been concluded that MECC and HPLC with ion-pairing mechanism could be successfully applied for the analysis of unknown dyes and their diazo components.

• Bulletin of the Korean Chemical Society
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• v.24 no.9
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• pp.1319-1323
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• 2003

This paper presents a successful demonstration of the on-line coupling of MEKC (micellar electrokinetic chromatography) to ESIMS (electrospray ionization mass spectrometry) for the quantitative analysis of seven s-triazine herbicides. The on-line MEKC-ESIMS was used to determine the structure of CE-separated peaks of seven triazine herbicides. The mixture of triazine herbicides was separated in a 20 mM sodium borate buffer (pH 8.5) containing 15 mM sodium dodecylsulfate (SDS) by using a bare fused-silica capillary. Electrospray ionization mass spectrometer was operated in the positive-ion mode when the mass spectra of seven triazine herbicides were observed from each peak, and the solution of water-methanol-formic acid (50/49/1 v/v/v) was used as a sheath liquid. The effects of SDS concentration, the run buffer pH, and the electric field on the separation of seven s-triazine herbicides were investigated. The MEKC-ESIMS detection showed 5 to 10 times higher sensitivity compared to the MEKC-UV detection. In addition, it did not need any pretreatment step.

• Archives of Pharmacal Research
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• v.24 no.6
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• pp.601-606
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• 2001

A simple assay method of recombinant human epidermal growth factor (rhEGF) in a pharmaceutical preparation was studied and validated by capillary electrophoresis (CE) using micellar electrokinetic chromatography (MEKC) techniques. Factors affecting the migration behavior and separation performances of the peptide; type of buffers pH, butler concentration, and concentration of sodium dodecyl sulfates (SDS) were investigated to optimize the analytical performance. CE was performed using running buffers 50.0 mM borate (pH 8.5) containing 12.5 mM SDS at 20 $mutextrm{V}$ of the applied voltage. Calibration curves for the rhEGF showed good linearity (r>0.999) over the wide dynamic range from 1.25 to $100{\mu\textrm{g}}/ml$. Sample analysis was performed by using standard addition method to eliminate the matrix effects of dosage vehicle. This method is assumed to be useful for quality control (QC) of various forms of pharmaceutical products of the peptide.

• Korean Chemical Engineering Research
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• v.52 no.1
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• pp.126-132
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• 2014

A pilot-scale electrokinetic (EK) separation field test ($2{\times}3{\times}0.2m^3$, $W{\times}L{\times}D$) was performed in a greenhouse to remove salts from saline soil. Initially, the greenhouse soil had high electrical conductivity (EC), about 9 dS/m, and contained mainly $Ca^{2+}$, $Cl^-$ and $SO_4^{2-}$ ions. After 2 weeks of EK treatment, the soil EC was reduced to 52% compared with its initial value. The EC reduction was mostly achieved within the first week (47%) due to removal of $Na^+$ and $Cl^-$ ions, but ions with a high adsorption capacity such as $Ca^{2+}$ and $SO_4^{2-}$ ions were difficult to be removed. During the EK test, the soil temperature increased and it reached around $50^{\circ}C$ at some regions. For in situ application to soils in cultivation, the current should be controlled to limit increases in temperature, especially near the cathodes. In conclusion, the in situ EK technique is feasible for the restoration of saline greenhouse soils in or no cultivation and an appropriate strategy is necessary for more effective remediation.