On-column sample concentration of high-ionic-strength samples in capillary electrophoresis

✍ Scribed by Sangryoul Park; Craig E. Lunte

• Publisher: John Wiley and Sons
• Year: 1998
• Tongue: English
• Weight: 118 KB
• Volume: 10
• Category: Article
• ISSN: 1040-7685
• DOI: 10.1002/(sici)1520-667x(1998)10:6<511::aid-mcs6>3.0.co;2-j

✦ Synopsis

High-ionic-strength samples result in poor electrophoretic separation efficiencies due to ''destacking'' of the sample. A simple method is described to stack high-ionic-strength samples without matrix modification prior to injection. Using a weak-acid buffer such as acetate as the background electrolyte, the electrokinetic injection of the sample is immediately followed by electrokinetic injection of an acid solution. The resulting titration of the background electrolyte produces a low-conductivity zone across which sample cations are focused. A sevenfold sensitivity enhancement was achieved with improved separation efficiency relative to normal electrokinetic injection.