ESI current oscillations for a high-resistivity fluid with the simultaneous visualization of the Taylor cone

Abstract

Low-frequency oscillations occurring in the electrospray of liquids with low electric conductivity were studied. Based on spectral measurements of oscillations in the range of voltages typically used in mass spectrometry, it was shown that the spectrum reveals the control frequency, which accounts for ≈80% of power oscillations, and a set of overtones. The magnitude of the main frequency varies in the range 200–800 Hz and increases with increasing voltage up to breakdown. Immediately after the collapse of oscillations, the most stable spraying mode is realized. A model describing the mechanism of oscillations due to the role of space charge accumulated on the counter electrode was proposed.