We present the investigation of droplet charging and charge transmission characteristics of an electro-flow focusing nozzle for desorption-based ambient ionization mass spectrometry. The electro-flow focusing geometry utilizes a concentrically flowing gas to focus a charged solvent stream through a small orifice, generating a steady liquid jet and charged droplet stream that impinges and ionizes the analyte and surface. Transmitted current measurements and a scaling analysis were incorporated to decouple analyte desorption and ionization from secondary droplet charging and to identify the regimes of operation, secondary droplet charge transport characteristics, and parameters limiting transmitted charge relevant for ambient ionization mass spectrometry.
Citation: Applied Physics Letters
Pub Type: Journals