Search PubMed⌕ Search

PubMed · 12569538

Stacking phenomena in electromigration: From basic principles to practical procedures.

Abstract

The review describes principles of procedures and techniques used in capillary zone electrophoresis for enhancement of sensitivity that are based on increasing analyte mass in its zone during the electromigration process, for which the term stacking is generally used. Attention is paid to intrinsic stacking in samples with low conductivity, transient isotachophoretic stacking applied in samples with high conductivity, and sweeping in micellar electrokinetic chromatography. Principles of these stacking schemes are explained, new procedures and instrumental arrangements are discussed, and all contributions involving stacking principles that have been published since the year 2000 are surveyed.

Explore related subjects

Keep this discovery

Explore connections, maps & timelines

BibTeXRIS

Marek Urbánek, Ludmila Krivánková, Petr Bocek. 2003. Stacking phenomena in electromigration: From basic principles to practical procedures.. https://doi.org/10.1002/elps.200390056

Cite the original work for its findings. Save a collection to share your selection of sources.

KEEP EXPLORING

Related citations

Enzyme assay for protein kinase using micellar electrokinetic chromatography with laser-induced fluorescence detection.

Micellar electrokinetic chromatography (MEKC) with laser-induced fluorescence (LIF) detection has been developed for a protein kinase assay. This protein kinase assay could readily determine the phosphorylation activity of substrate peptide kemptide using cAMP-dependent protein kinase (PKA) as a model enzyme. Kemptide and phosphorylated kemptide could be reacted with 7-fluoro-4-nitrobenzo-2-oxa-1,3-diazole (NBD-F) as a fluorescence derivatization reagent for LIF detection by directly adding NBD-F into the PKA enzymatic reaction mixture. These derivatives of substrate and product were separated and detected within the analysis time of 5 min by micellar electrokinetic mode using a mixture of sodium dodecylsulfate and methanol as a running buffer. Good linearity of the peak response of the phosphorylated kemptide was obtained over the range of 1-20 mU/tube of PKA in the assay. The relative standard deviation of the peak areas of the phosphorylated kemptide using 2, 5 and 10 mU/tube of PKA were calculated to <10.4%, indicating that the assay was reproducible. Also, IC(50) values of six PKA inhibitors, the K(i) value and the inhibition pattern of one inhibitor, which were calculated to estimate by the variation of the peak area of the phosphorylated kemptide using 5 mU/tube of PKA, were consistent with the published data. The sensitivity of the assay was higher than that of enzyme-linked immunosorbent assay (ELISA) for PKA phosphorylation activity, as IC(50) values, K(i) value, and the inhibition mechanism of inhibitors could be estimated using one-tenth amounts of PKA, compared with that of ELISA. The MEKC-LIF is expected to be very useful for protein kinase assay and its application to the estimation of inhibitors because this method does not entail experimentally troublesome procedures such as the preparation of antibody or fluorescence-labeled substrate.

Chromatography, Micellar Electrokinetic Capillary↗

Determination of urinary hippuric acid by micellar electrokinetic capillary chromatography.

We propose a method for the simultaneous determination of hippuric acid (HA) and creatinine based on capillary micellar electrokinetic chromatography. Experimental conditions were 20 mM sodium phosphate, pH 7.20, 25 mM sodium dodecyl sulfate, 5% (v/v) acetonitrile. Electropherograms evidenced HA and creatinine peaks in less than 12 min. The method showed good linearity for both analytes and satisfactory within-day precision. The present method, which is accurate, sensitive, rapid and simple, may be applied to single-spot urine samples.

Chromatography, Micellar Electrokinetic Capillary↗

Screening of octanol-water partition coefficients for pharmaceuticals by pressure-assisted microemulsion electrokinetic chromatography.

A rapid screening assay for the determination of octanol-water partition coefficients (log P(OW)) of pharmaceuticals was developed by using pressure-assisted microemulsion electrokinetic chromatography (MEEKC). The microemulsion system contains 50 mM sodium dodecyl sulfate, 0.87 M l-butanol, 82 mM heptane, and 50 mM borate-phosphate (2:3) at pH 10. Ten standard compounds with known log P(OW) values from -0.26 to 4.88 were used for constructing the calibration curve of log P(OW) against the MEEKC retention factor, log k. The log P(OW) values of the compounds were calculated based on the log k values measured by MEEKC and the slope and intercept of the calibration curve. For 13 literature and 32 Roche compounds, about 90% of the log P(OW) values measured by MEEKC are within 0.5 log units of the values from the literature and potentiometric titration. The throughput is about 2 samples/h using +20 kV voltage plus 5 mbar air pressure for separation. This MEEKC method is applicable for log P(OW) screening of weakly basic, weakly acidic, and neutral pharmaceuticals with log P(OW) = 0-5 and pKa < or = 10.

Chromatography, Micellar Electrokinetic Capillary↗