Fabrication of Dense Polymer Nozzle Array on Microstructured Fibers for Multi-Electrospray Ionization

摘要

A rational design for a microstructured fiber capable of true multiple electrosprays was fabricated in silica. The MSF has 9 channels in a radial pattern to minimize interchannel electric field inhomogeneities, and has dimensions compatible with current fluidic fitting standards in microfluidic systems and nanoESI-MS. PolyDVB nozzles facilitate and maintain the individual electrosprays in stable cone-jet mode, enhancing ESI-MS stability. The MSF emitters can be employed with a wide variety of solvent conditions, voltages and flow rates. Linear relationship between the measured spray current and the square root of the number of independent electrosprays of the emitters confirms the multi-electrospray behaviour. LC/MS analysis of a 10 amol BSA digest using the emitters showed good chromatographic efficiency. The spectra of 54 replicate injections of 10 fmol BSA demonstrated good emitter reproducibility and long term stability. The emitters are robust and clog resistant, and are relatively facile to fabricate.