Classification of electrospray axial regimes as revealed by spray current measurements

A coherent classification of electrospray axial regimes is provided based on non-linear fluid dynamics as revealed by spray current measurements and fast time-lapse imaging of the electrified meniscus. The classification includes two periodic (dripping, pulsating), two transient/chaotic (burst, astable), and two stationary (cone-jet, jetting) regimes. The dripping faucet phase diagram is described as a particular case of a more complex electrospray phase diagram. Spray current measurements and electrospray characteristic curves are presented as essential for the diagnosis of the electrospray operation and the transition between its various regimes. Reaching a consensus on regime nomenclature and a standardized approach to designate transitions between electrospray regimes is suggested. Finally, the effect of the electrospray operating regime on the mass spectrometer signal is briefly summarized.