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Published on: April 18, 2014
Electroosmotic flow and injection: application to conductimetry.
1Department of Chemistry and Laboratory for Surface Studies, University of Wisconsin-Milwaukee, Milwaukee, WI 53201, USA.
Talanta
|October 1, 1994
Summary
Electroosmotic propulsion and sample injection were achieved using a fused silica capillary. This method offers high sensitivity and low cell volume for various concentrations.
Area of Science:
- Analytical Chemistry
- Electrochemistry
Background:
- Fused silica capillaries are widely used in separation science.
- Electroosmotic flow is a key phenomenon in capillary electrophoresis.
- Precise sample injection is crucial for quantitative analysis.
Purpose of the Study:
- To investigate electroosmotic solution propulsion and sample injection.
- To establish the basis for high sensitivity and low cell volume in this system.
- To demonstrate the application in conductivity measurements.
Main Methods:
- Utilized a fused silica capillary tube (50-100 microm i.d., 4-7 cm length) with a wall break for electrolytic contact.
- Applied an electric field of approximately 150 V/cm.
- Monitored voltage at the capillary break using potentiometry with a bridge configuration.
Main Results:
- Achieved electroosmotic propulsion and sample injection across a concentration range of 10 microM to 100 mM.
- Established high sensitivity (70 mV/microM) and low cell volume (20 nl).
- Successfully performed tap water conductivity measurements using a CaCl(2) reference solution.
Conclusions:
- Electroosmotic propulsion and sample injection in fused silica capillaries are feasible and efficient.
- The developed method provides high sensitivity and low sample volume, suitable for various analytical applications.
- This technique demonstrates potential for in-situ conductivity measurements.
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