Improvement of the long-term stability of polyimide-coated fused-silica capillaries used in capillary electrophoresis and capillary electrochromatography.
Swelling of the polyimide coating of fused-silica capillaries in acetonitrile-containing buffers was found to be the reason for several problems in capillary electrophoresis (CE) and capillary electrochromatography (CEC). Scanning electron microscopy photographs of the ends of raw fused-silica tubing showed that the coating becomes soft and increases its volume after longer contact with such buffers. As a consequence, separation efficiency can deteriorate, the capillary ends can clog or break off. To prevent swelling of the polyimide coating, fused-silica capillaries used in CE or CEC were heated at 300 degrees C for a longer period of time which improved their long-term stability in comparison to raw fused-silica tubing.
University of Ulm, Department of Analytical and Environmental Chemistry, Germany.
Fred
F
Baeuml
Thomas
T
Welsch
D020374:Chromatography, Micellar Electrokinetic Capillary / Q000295:instrumentation*; D019075:Electrophoresis, Capillary / Q000295:instrumentation*; D007094:Imides / Q000737:chemistry*; D008855:Microscopy, Electron, Scanning; D011108:Polymers
D007094:Imides; D011108:Polymers