Modeling the zeta potential of silica capillaries in relation to the background electrolyte composition

2003 ◽  
Vol 24 (10) ◽  
pp. 1587-1595 ◽  
Author(s):  
Claudio L. A. Berli ◽  
María V. Piaggio ◽  
Julio A. Deiber
Keyword(s):  
Zeta Potential ◽  
Background Electrolyte ◽  
Electrolyte Composition ◽  
Silica Capillaries

Variation of zeta-potential with temperature in fused-silica capillaries used for capillary electrophoresis

2006 ◽  
Vol 27 (3) ◽  
pp. 672-676 ◽  
Author(s):  
Christopher J. Evenhuis ◽  
Rosanne M. Guijt ◽  
Miroslav Macka ◽  
Philip J. Marriott ◽  
Paul R. Haddad
Keyword(s):  
Capillary Electrophoresis ◽  
Zeta Potential ◽  
Fused Silica ◽  
Fused Silica Capillaries ◽  
Silica Capillaries

scholarly journals Layer-by-Layer Assembly of Polysaccharides and 6,10-Ionene for Separation of Nitrogen-Containing Pharmaceuticals and Their Enantiorecognition by Capillary Electrophoresis

2015 ◽  
Vol 2015 ◽  
pp. 1-9 ◽  
Author(s):  
Anna Ioutsi ◽  
Elena Shapovalova ◽  
Aleksandra Prokhorova ◽  
Oleg Shpigun
Keyword(s):  
Dextran Sulfate ◽  
Background Electrolyte ◽  
Channel Blockers ◽  
Layer By Layer ◽  
Dynamic Coating ◽  
Rapid Separation ◽  
Sample Matrix ◽  
Silica Capillaries ◽  
Modified Layer ◽  
Layer Assembly

Two silica capillaries modified layer-by-layer with 6,10-ionene and N-(3-sulfo-3-carboxy)-propionylchitosan (SCPC) and with 6,10-ionene and dextran sulfate (DS) were prepared and investigated. Dynamic coating of the capillary efficiently reduces the adsorption of the background electrolyte, sample matrix components, and analytes on its inner wall. Such coatings effect good reproducibility and sensitivity of determination. We demonstrate that separation of betablockers, calcium channel blockers, alpha-adrenergic agonists, H1-blockers, and diuretics was the most efficient and rapid separation with a capillary modified with dextran sulfate. Tetrahydrozoline, carbinoxamine, and furacilin, which are commonly employed as treatments for allergic rhinitis, were identified in human urea. Their concentrations, independently verified by HPLC, were found to be5.3±0.8,6.6±0.5, and0.9±0.2 μg mL−1, withLOD=0.07, 0.03, 0.10 μg mL−1, andLOQ=1.0, 0.8, 0.6 μg mL−1, respectively.

Adsorption of calcium at the zinc sulphide-water interface

1977 ◽  
Vol 30 (4) ◽  
pp. 733 ◽  
Author(s):  
MS Moignard ◽  
RO James ◽  
TW Healy
Keyword(s):  
Ion Exchange ◽  
Zeta Potential ◽  
Calcium Ions ◽  
Reasonable Agreement ◽  
Background Electrolyte ◽  
Zinc Sulphide ◽  
Pure Zinc ◽  
Subsequent Decrease ◽  
Ph Dependent ◽  
Direct Adsorption

The uptake of aqueous calcium ions by pure zinc sulphide colloids has been measured by direct adsorption and microelectrophoresis techniques. This uptake is pH dependent, with significant adsorption commencing at approximately pH 7 and increasing up to pH 11. The electrokinetic measurements also reflect the interfacial presence of Ca2+. The zeta-potential of zinc sulphide particles is more positive in the presence of Ca(NO3)2 solutions than in simple background electrolyte (KNO3) solutions. If the concentration of calcium ion is sufficiently high, the zeta-potential changes sign c. pH 8. Adsorption and simple ion-exchange models which have been successfully applied to other oxide and sulphide minerals are not particularly successful. However, reasonable agreement between direct adsorption and electrophoresis data has been obtained from the simple Gouy-Chapman-Stern double layer model, provided that: (i) the surface potential is approximately given by the Nernst equation; (ii) the specific adsorption potential of Ca2+ on ZnS increases from about 0 kBT/ion, at low pH values below pH 7, up to about - 6.5 kBT/ion, at pH 8 and higher. An ion-exchange model could only be used to give reasonable agreement with experiment at low adsorption densities. This exchange reaction is not strongly pH dependent and involves the release of one proton for every three Ca2+ ions adsorbed. These results would indicate that Ca2+ adsorption at the ZnS-H2O interface involves the movement of calcium ions into the Stern plane without the release of an equivalent number of protons into the diffuse layer and bulk solution. The subsequent decrease in zeta-potential caused by Ca2+ adsorption may be related to deteriorating flotation recoveries and grades observed for sphalerite in the presence of Ca2+ solutions when lime is used as a pH modifier and/or suppressant for pyrite.

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