Metallized sheathless electrospray emitters for use in capillary electrophoresis orthogonal time-of-flight mass spectrometry

Chromium-gold coated fused silica emitters for electrospray ionization have been fabricated with lifetimes upwards of 100 hours. The coating on these emitters is extremely durable withstanding electrical discharges, abrasion and mechanical stress. Usable flow rates range from 30 nL/min to 1 µL/min using both standard electrospray solutions and aqueous buffers. Coated capillary electrophoresis columns incorporating the emitter provide excellent separation, low limits of detection (70–700 attomoles for peptides), and are easy to use. Performance of the emitters in continuous infusion experiments and capillary electrophoresis/electrospray ionization mass spectrometry applications are presented.