Microchip Micellar Electrokinetic Chromatography Based on One Functionalized Ionic Liquid and Its Excellent Performance on Proteins Separation

Herein, one water-soluble functionalized ionic liquid (IL), 1-butyl-3-methylimidazolium dodecanesulfonate (BAS), was designed, investigated and successfully applied to microchip micellar electrokinetic chromatography (MEKC) construction. It possessed the properties of both IL and surfactant. A fairly stable pH value similar to 7.4, which was fit to pH values of general biological buffers, was nicely placed at the optimum concentration of 20 mM BAS solution. While applying BAS solution as running buffer in poly(dimethylsiloxane) (PDMS) microfluidic systems, significantly enhanced electroosmotic flow (8-fold) and resolutions between analytes were obtained than that using other supporting electrolytes or surfactants.

Separation and detection of narcotic drugs on a microchip using micellar electrokinetic chromatography and electrochemiluminescence

A new approach for fast and sensitive electrochemiluminescence (ECL) detection of narcotic drugs on a microchip after separation by micellar electrokinetic chromatography (MEKC) is presented, taking the cocaine and its hydrolysate ecgonine as the test analytes. The mixture of hydrophilic BMIMBF4 ionic liquid (IL) and sodium dodecyl sulfate (SDS) was used directly as the buffer of MEKC with less noisy baselines, lower electrophoretic current and satisfactory separation performance.

Analysis of five pharmacologically active compounds from the Tibetan medicine Elsholtzia with micellar electrokinetic capillary chromatography

A high performance capillary electrophoresis method with diode array detector detection for the determination of five bioactive ingredients in Tibetan medicine Elsholtzia, namely quercetin, rutin, saussurenoside, kaempferol, and oleanolic acid, has been developed. The effects of several factors, such as the acidity, concentration of running buffer, separation voltage, temperature, and SDS concentration were investigated. The optimal conditions were 44 mmol/L boric acid running buffer (pH 8.5), 45 mmol/L SDS, 16 KV voltage, 20 degrees C, and 10.0% (V/V) of acetonitrile. Under the optimum conditions, five components could be separated with a good baseline resolution within 17 min. The calibration curves showed good linear relationship over the concentration range of 5 x 10(-4)similar to 0.1 mg/mL for quercetin, rutin, saussurenoside, kaempferol, and 1 x 10(-3) similar to 0.1 mg/mL for oleanolic acid. The average recoveries of the method and RSD were ( 99.2%, 3.2%) for quercetin, (102.1%, 2.1%) for rutin, (99.4%, 1.5%) for saussurenoside, (98.9%, 1.8%) for kaempferol, and (99.0%, 2.9%) for oleanolic acid, respectively. The detection limits (S/N = 3) were 1.1 x 10(-4) mg/mL for quercetin, 2.6 x 10(-4) mg/mL for rutin, 1.8 x 10(-4) mg/mL for saussurenoside, 2.9 x 10(-4) mg/mL for kaempferol, and 6.3 x 10(-4) mg/mL for oleanolic acid, respectively. The method was simple, rapid, and reproducible and could be applied for the determination of quercetin, rutin, saussurenoside, kaempferol, and oleanolic acid in Tibetan medicine Elsholtzia, and the assay results were satisfactory.

Effects of organic modifiers on solute retention and electrokinetic migrations in micellar electrokinetic capillary chromatography

Influences of seven organic modifiers, including urea, methanol (MeOH), dioxane (DIO), tetrahydrofuran (THF), acetonitrile (ACN), 1-propanol (1-PrOH) and 2-propanol (2-PrOH), on the solute retention and the electrokinetic migrations in micellar electrokinetic capillary chromatography (MEKC) are investigated with sodium dodecyl sulfate (SDS) micelle as pseudostationary phase. It is observed that in the limited concentration ranges used in the MEKC systems the effect of organic modifier concentration on the retention can be described by the equation logk'=logk'(w)-SC for most binary aqueous-organic buffer, but deviations from this retention equation are observed at ACN and particularly THF as organic modifiers. With parameter S as a measure of the elutropic strength, the elutropic strength of the organic modifiers is found to follow a general order urea

DC dielectrophoretic focusing of particles in a serpentine microchannel

Focusing particles into a tight stream is usually a necessary step prior to separating and sorting them. We present herein a proof-of-concept experiment of a novel particle focusing technique in DC electrokinetic flow through a planar serpentine microchannel. This focusing stems from the cross-stream dielectrophoretic motion induced within the channel turns. The observed particle focusing behavior is consistent with the predicted particle trajectories from a numerical modeling.

Simultaneous determination of pethidine and methadone by capillary electrophoresis with electrochemiluminescence detection of tris(2,2 '-bipyridyl)ruthenium(II)

In this paper, we described a simple and rapid method, capillary electrophoresis with electrochemiluminescence (CE-ECL) detection using tris(2,2'-bipyridyl)ruthenium(II) (Ru(bpy)(3)(2+)), to simultaneously detect pethidine and methadone. Analytes were injected to separation capillary of 67.5 cm length (25 mu m i.d., 360 mu m o.d.) by electrokinetic injection for 10 s at 10 kV.

A novel technique for NACE coupled with simultaneous electrochemiluminescence and electrochemical detection for fast analysis of tertiary amines

A simultaneous electrochemiluminescence (ECL) and electrochemical (EC) detection scheme for NACE was presented for fast analysis of tertiary amines. Both ECL and EC signals were generated at the same Pt electrode. Triethylamine (TEA), tripropylamine (TPrA), chlorpromazine, promethazine, and dioxopromethazine (DPZ) were selected to validate NACE-ECL/EC dual detection strategy. The linear ranges for TEA and TPrA were 0.01-500 and 0.01-10 mu M with the detection limits of 8.0 and 5.0 nM (S/N=3), respectively. The RSDs (n = 6) of the migration time and the ECL intensity for 1 mu M TEA and 0.5 mu M TPrA were 0.1 and 2.8%, and 0.2 and 1.8% with theoretical plate numbers of 180 000 and 700 000 per meter, respectively. These two analytes could be separated within 92 s and the Pt electrode did not need reactivation during the experiments.

Ionic liquids used in and analyzed by capillary and microchip electrophoresis

This review, covering reports published from 2001 to December 2008, shows how ionic liquids (ILs) have made significant contributions in the improvement of capillary and microchip electrophoresis (CE and mu CE) for the separation and detection of analytes such as phenols and aromatic acids, metal ions, medicines, enantiomers. biological materials, etc. Furthermore, CE methods applied in the sensitive and accurate determination of physico-chemical properties of ILs have been summarized. Accordingly, research vacancies and future development trends in these areas are discussed.