posted on 2020-06-02, 09:29authored byColbert
F. Miller, Benjamin J. Burris, Abraham K. Badu-Tawiah
Analytical
characteristics of contained electrospray ionization
(ESI) are summarized in terms of its potential to modify the analyte
solution during the stages of droplet formation to provide opportunities
to generate native versus denatured biomolecular gas-phase ions, without
the need for bulk-phase analyte modifications. The real-time modification
of the charged microdroplets occurs in a cavity that is included in
the outlet of the contained-ESI ion source. Close examination of the
inside of the cavity using a high-speed camera revealed the formation
of discrete droplets as well as thin liquid films in the droplets
wake. When operated at 20 psi N2 pressure, the droplets
were observed to move at an average speed of 8 mm/s providing ∼1
s mixing time in a 10 mm cavity length. Evidence is provided for the
presence of highly reactive charged droplets based on myoglobin charge
state distribution, apo-myoglobin contents, and ion mobility drift
time profiles under different spray conditions. Mechanistic insights
for the capture of vapor-phase reagents and droplet dynamics as influenced
by different operational modes are also described.