Dual Nano-Electrospray and Mixing in the Taylor Cone

Abstract : Dual-channel nano-electrospray has recently become an ionization technique of great promise especially in biologi-cal mass spectrometry. This unique approach takes advantage of the mixing processes that occurs during electrospray. Under-standing in more detail the fundamental principles influencing spray formation further study of the origins of the mixingprocesses: (1) in a Taylor cone region, (2) in charged droplets or (3) in both environments. The dual-channel emitters were mad efrom borosilicate theta-shape glass tubes (O.D. 1.2 mm) and had a tip diameters of less than 4µm. Electrical contact wasachived by deposition of a thin film of an appropriate metal onto the surface of the emitter. The experimental investigation ofthe Taylor cone formation in a dual-channel electrospray emitter has been carried out by injection of polystyrene beads(diameter 3µm) at very low concentrations into one of the channels of the non-tapered theta-glass tubes. High-speed cameraexperiments were set up to visualize the mixing processes in Taylor cone regions for dual-channel emitters. Mass spectra fromdual nano-electrospray are presented.Keywords : nano-electrospray, theta-shaped dual channel emitters, Taylor cone, mass spectrometry