Influence of the electrical double-layer on electroosmotic flow in capillary electrochromatography

Cikalo, Maria G.; Bartle, Keith D.; Myers, Peter

doi:10.1016/s0021-9673(98)00865-6

Cited by 70 publications

(62 citation statements)

References 29 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…ACN was selected as the organic modifier in MEKC because of its superior EOF-promoting ability [29,30]. The results showed higher contents of ACN enhanced the separation performance, albeit at the cost of an increase in separation time with an increase of ACN content from 10 to 40 % (v/v).…”

Section: Optimization Of Mekc Conditionsmentioning

confidence: 99%

Dual cloud point extraction coupled with hydrodynamic-electrokinetic two-step injection followed by micellar electrokinetic chromatography for simultaneous determination of trace phenolic estrogens in water samples

Wen

Liu

et al. 2013

Anal Bioanal Chem

View full text Add to dashboard Cite

A dual cloud point extraction (dCPE) off-line enrichment procedure coupled with a hydrodynamic-electrokinetic two-step injection online enrichment technique was successfully developed for simultaneous preconcentration of trace phenolic estrogens (hexestrol, dienestrol, and diethylstilbestrol) in water samples followed by micellar electrokinetic chromatography (MEKC) analysis. Several parameters affecting the extraction and online injection conditions were optimized. Under optimal dCPE-two-step injection-MEKC conditions, detection limits of 7.9-8.9 ng/mL and good linearity in the range from 0.05 to 5 μg/mL with correlation coefficients R 2 ≥0.9990 were achieved. Satisfactory recoveries ranging from 83 to 108 % were obtained with lake and tap water spiked at 0.1 and 0.5 μg/mL, respectively, with relative standard deviations (n=6) of 1.3-3.1 %. This method was demonstrated to be convenient, rapid, cost-effective, and environmentally benign, and could be used as an alternative to existing methods for analyzing trace residues of phenolic estrogens in water samples.

show abstract

Section: Optimization Of Mekc Conditionsmentioning

confidence: 99%

Dual cloud point extraction coupled with hydrodynamic-electrokinetic two-step injection followed by micellar electrokinetic chromatography for simultaneous determination of trace phenolic estrogens in water samples

Wen

Liu

et al. 2013

Anal Bioanal Chem

View full text Add to dashboard Cite

show abstract

“…As mentioned above, the linear relationship of µ eo -I -0.5 to mean µ eo ＝b＋aI -0.5 was frequently used. [1][2][3][4]7,8] But the linear relationship was also found usable in very limited concentration range. In the paper, by real experiment data, quantitative study of mathematical expression of the linear relationship between electroosmotic mobility and buffer concentration was discussed to explain it.…”

Section: Introductionmentioning

confidence: 99%

Linear Expression of the Mathematical Relationship between Electroosmotic Mobility and Buffer Concentration

Gao

Bao

2006

Chin. J. Chem.

View full text Add to dashboard Cite

It was believed that electroosmotic mobility µ eo is inversely proportional to the square root of the ionic strength I. But the linear relationship for regression analysis was expressed differently in different papers. The paper studied the linear expression of the mathematical relationship between µ eo and c (background buffer concentration) by mathematical transform and real experimental data. µ eo values of fused silica capillary were determined in four buffer systems. Their experimental conditions were controlled carefully for decreasing temperature difference ∆T and pH difference ∆pH in 50 µm ID capillary, in which no double layer overlap existed. The linear relationship between the reciprocal of electroosmotic mobility and the square root of concentration (or ionic strength) was derived by mathematical method. The regression analysis of experimental data was shown to well correspond to the relationship. The constants in regression equation could be well defined and the calculated results were acceptable.

show abstract

“…This might be caused by the fact that with the decrease of the electrolyte concentration, the zeta potential of the capillary surface is increased, which might enhance the adsorption of protein to the capillary surface, leading to band-broadening. When the concentration is changed from 25 mM to 75 mM, the zeta potential decreases and the adsorption of protein to the capillary surface becomes weak (this phenomenon has been described in previous works [26,27]), therefore the sample signal intensity increases. However, with the further increase of electrolyte concentration from 75 mM to 125 mM, high-concentration NH 4 1 might compete with the sample ions in the conversion process leading to the decrease of the signal intensity.…”

Section: Effects Of the Electrolyte Concentration In The Mobile Phasementioning

confidence: 55%

On‐line concentration of proteins in pressurized capillary electrochromatography coupled with electrospray ionization‐mass spectrometry

et al. 2005

View full text Add to dashboard Cite

Pressurized capillary electrochromatography (pCEC) and electrospray ionization-mass spectrometry (ESI-MS) have been hyphenated for protein analysis. Taken cytochrome c, lysozyme, and insulin as samples, the limits of detection (LODs) for absolute concentrations are 10 211 mol (signal-to-noise ratio S/N = 3) with relative standard deviations (RSDs) of retention time and peak area, respectively, of less than 1.7% and 4.8%. In order to improve the detection sensitivity, on-line concentration by fieldenhanced sample-stacking effect and chromatographic zone-sharpening effect has been developed, and parameters affecting separation and detection, such as pH and electrolyte concentration in the mobile phase, separation voltage, as well as enrichment voltage and time, have been studied systematically. Under the optimized conditions, the LODs of the three proteins could be decreased up to 100-fold. In addition, the feasibility of such techniques has been further demonstrated by the analysis of modified insulins at a concentration of 20 mg/mL.

show abstract

Influence of the electrical double-layer on electroosmotic flow in capillary electrochromatography

Cited by 70 publications

References 29 publications

Dual cloud point extraction coupled with hydrodynamic-electrokinetic two-step injection followed by micellar electrokinetic chromatography for simultaneous determination of trace phenolic estrogens in water samples

Dual cloud point extraction coupled with hydrodynamic-electrokinetic two-step injection followed by micellar electrokinetic chromatography for simultaneous determination of trace phenolic estrogens in water samples

Linear Expression of the Mathematical Relationship between Electroosmotic Mobility and Buffer Concentration

On‐line concentration of proteins in pressurized capillary electrochromatography coupled with electrospray ionization‐mass spectrometry

Contact Info

Product

Resources

About