title: Characterization and application of droplet spray ionization for real-time reaction monitoring.
abstract: The ionization source for real-time reaction monitoring has attracted tremendous interest in recent years. We have previously reported a reliable approach in which droplet spray ionization (DSI) was used for monitoring chemical reactions in real-time. Herein, we systematically investigated the characterization and application of DSI for real-time reaction monitoring.
  
  
  
  Analyte ions are generated by loading a sample solution onto a corner of a microscope cover glass positioned in front of the MS inlet and applying a high voltage to the sample. The tolerance to positioning, solvent effect, spray angle and spray time were investigated. Extension to real-time monitoring of macromolecule reactions was also demonstrated by the charge state change of cytochrome c in the presence of acetic acid.
  
  
  
  The corner could be positioned within an area of approximately 10 × 6 × 5 mm (x, y, z) in front of the MS inlet. The broad polarities of solvents from methanol to PhF were suitable for DSI. It featured monitoring real-time changes in reactions on the time scale of seconds to minutes. A real-time charge state change of cytochrome c was captured.
  
  
  
  DSI-MS features ease of use, durability of the spray platform and reusability of the ion source. Eliminating the need for a sample transport capillary, DSI opens a new avenue for the in situ analysis and real-time monitoring of short-lived key reaction intermediates even at subsecond dead times. Copyright © 2016 John Wiley & Sons, Ltd.
authors.affiliation: State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology, Weihai, China.
authors.forename: Hong
authors.initials: H
authors.lastname: Zhang
authors.affiliation: School of Marine Science and Technology, Harbin Institute of Technology at Weihai, Weihai, China.
authors.forename: Na
authors.initials: N
authors.lastname: Li
authors.affiliation: School of Marine Science and Technology, Harbin Institute of Technology at Weihai, Weihai, China.
authors.forename: Xiao-di
authors.initials: XD
authors.lastname: Li
authors.affiliation: School of Marine Science and Technology, Harbin Institute of Technology at Weihai, Weihai, China.
authors.forename: Jie
authors.initials: J
authors.lastname: Jiang
authors.affiliation: School of Marine Science and Technology, Harbin Institute of Technology at Weihai, Weihai, China.
authors.forename: Dan-Dan
authors.initials: DD
authors.lastname: Zhao
authors.affiliation: State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology, Weihai, China.
authors.forename: Hong
authors.initials: H
authors.lastname: You
mesh_terms: D004867:Equipment Design; D011506:Proteins / Q000737:chemistry; D012997:Solvents / Q000737:chemistry; D021241:Spectrometry, Mass, Electrospray Ionization / Q000295:instrumentation / Q000379:methods*; D013997:Time Factors
chemical_list: D011506:Proteins; D012997:Solvents