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Protein and peptide separations on high surface area capillaries
J J Pesek1, M T Matyska, S Swedberg
1Department of Chemistry, San Jose State University, CA 95192, USA. pesek@sjsu.edu
Electrophoresis
|September 28, 1999
Summary
Etching fused-silica capillaries with ammonium hydrogen difluoride enhances capillary electrochromatography separations. This method improves peptide mapping resolution and protein retention, indicating significant chromatographic effects.
Area of Science:
- Analytical Chemistry
- Separation Science
Background:
- Capillary electrochromatography (CEC) is a powerful separation technique.
- Fused-silica capillaries are commonly used but can be modified to improve performance.
Purpose of the Study:
- To evaluate ammonium hydrogen difluoride-etched capillaries as a CEC separation medium.
- To compare the performance of etched versus unetched fused-silica capillaries.
Main Methods:
- Capillary electrochromatography was performed using both etched and unetched fused-silica capillaries.
- Separations were tested with a tryptic digest of transferrin and a four-component protein sample.
- Experimental conditions, including voltage and Polybrene coating, were controlled and adjusted.
Main Results:
- The etched capillary provided better resolution and longer retention for the transferrin digest compared to the unetched capillary.
- Resolution on the etched capillary was further improved by reducing the voltage.
- The etched capillary also showed longer retention for a protein mixture, with lower calculated electrophoretic mobilities after accounting for electroosmotic flow.
Conclusions:
- Ammonium hydrogen difluoride-etched capillaries exhibit chromatographic effects that enhance CEC separations.
- Etched capillaries offer improved resolution and retention compared to standard fused-silica capillaries.
- This modification presents a promising approach for optimizing CEC-based analyses.