Subattomole-sensitivity microchip nanoelectrospray source with time-of-flight mass spectrometry detection

A microfabricated microfluidic device coupled with a nanospray tip for elec trospray ionization of dilute solutions is-described. The device has been i nterfaced with a time-of-flight mass spectrometer and evaluated for sensiti ve, high-speed detection of peptides and proteins. The electrospray: voltag e was applied through the microchip to the nanospray capillary that was att ached at the end of a microfabricated channel. Fluid delivery rates were 20 -39 nL min(-1) through the hybridized structure without any pressure assist ance. On-line microchip electrophoresis has been demonstrated and the effec t of the capillary-chip junction on band broadening examined. Full mass spe ctra are acquired within 10-20 ms at 50-100 spectra s(-1) storage rates. De tection of subattomole levels of sample from a 100 nM solution is demonstra ted for infusion experiments.