PubMed Health⌕ Search
Home/Archive/PubMed

PubMed · 11045491

Electrochromatography.

N W Smith·A S Carter-Finch
View original source ↗Export metadata ↓

Abstract

Although Mould and Synge were credited with the first demonstration of the use of electroosmotic flow to drive a liquid in a thin-layer chromatography system, it was the work of Knox and Grant that extensively detailed much of both the theoretical and practical implications of capillary electrochromatography. This review is aimed at giving a very broad outline of the progression of this technique since the late 1980s up to the present time, including some of the current limitations. Examples will be given of the analysis of a wide variety of materials including neutral, acidic, basic and chiral pharmaceutical compounds, along with some of the instrumentation used for this technique.

Explore related subjects

Chromatography, Micellar Electrokinetic CapillaryJournal ArticleReview

Keep this discovery

Explore connections, maps & timelines

BibTeXRIS

N W Smith, A S Carter-Finch. 2000-09-15. Electrochromatography.. https://doi.org/10.1016/s0021-9673(00)00470-2

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

KEEP EXPLORING

Related citations

PubMed2003

Solid-phase extraction and sample stacking-micellar electrokinetic capillary chromatography for the determination of multiresidues of herbicides and metabolites.

Micellar electrokinetic capillary chromatography (MEKC) with diode array detection was used for the separation of 13 compounds (eight herbicides widely used in agriculture: metribuzin, lenacil, ethofumesate, atrazine, terbutryn, isoproturon, chlorotoluron and linuron, and five of their principal degradation products; namely, deethylatrazine, 2-hydroxyatrazine, deethyl-2-hydroxyatrazine, deisopropylatrazine and 3-chloro-4-methylphenylurea). Peak separation for the 13 analytes was not successful when a single surfactant system was employed, neither sodium dodecyl sulfate (SDS) nor dioctyl sulfosuccinate (DOSS) sodium salt. However, a mixture of these herbicides was successfully separated using a mixed micellar system involving SDS-DOSS in less than 14 min. An application study of an on-line concentration technique for MEKC was carried out to enhance sensitivity. The optimized on-line stacking procedure consisted simply of the addition of 50 mM of sodium chloride to the injection sample, the stacking effect being more intensive as analyte polarity increased. When this stacking procedure was combined with an off-line sample preconcentration step, based on solid-phase extraction, analytes could be detected in the ppb range. The whole method was applied to ultra-high-quality and natural waters. Linear relationships between the analytical signal and the initial analyte concentration were found to be independent of the type of water, except for the more polar analytes for which small differences were observed.

Chromatography, Micellar Electrokinetic Capillary↗
PubMed2003

Influencing electroosmotic flow and selectivity in open tubular electrochromatography by tetrakis(pentafluorophenyl)porphyrin as capillary wall modifier.

A physically adsorbed and covalently bonded porphyrin derivative, 5,10,15,20-tetrakis(pentafluorophenyl)porphyrin, H2TPFPP, has been used as a fused-silica capillary wall modifier in open tubular capillary electrochromatography (OT-CEC), and its influence on the electroosmotic flow (EOF) velocity and on the selectivity of OT-CEC separations of a set of model aromatic carboxylic acids has been tested. Whereas most of the coatings of this category bring about an increase in selectivity with a concomitant slow down of the EOF, H2TPFPP coating, depending on pH of the background electrolyte used, resulted both in decreasing of EOF at pH 8.5 by 5% and in increasing of EOF by 10-43% at pH 6 and 5, respectively. The separation efficiency and the resolution of aromatic carboxylic acids separation in coated capillaries, namely in that one with covalent coating, were better than in the bare fused-silica capillary. The perspectives of H2TPFPP as capillary wall modifier are visualized in introducing well defined electroosmotic properties of materials used for miniaturized separation channels preparation in chip-based electromigration devices.

Chromatography, Micellar Electrokinetic Capillary↗
PubMed2003

Affinity electrochromatography of acidic drugs using a liposome-modified capillary.

Liposomes can be effectively deposited on the inner surface of a capillary wall by flushing the electrophoretic system with a liposome suspension followed by air-drying of the capillary and removal of the excess of loosely bound liposomes by a 0.1 M NaOH wash. It was demonstrated that capillaries prepared in this way could be used for studies of analyte (drug)-liposome binding. The results were expressed as free binding energy changes [delta(deltaG0)] relatively to an arbitrarily selected standard (acetylsalicylic acid). The results were compared to [delta(deltaG0)] changes obtained from binding studies effected by capillary electrophoresis using a stable liposome plug in a capillary with minimized endoosmotic flow. Good agreement of data reported in the literature (without correction for the residual endoosmotic flow), our previous data obtained in a similar way (however, after the correction for the residual endoosmotic flow) and data obtained by the immobilized liposome affinity electrochromatography reported in this communication was achieved.

Chromatography, Micellar Electrokinetic Capillary↗