New Processes for Ionizing Nonvolatile Compounds in Mass Spectrometry: The Road of Discovery to Current State-of-the-Art

This Perspective covers discovery and
mechanistic
aspects as well as initial applications of novel ionization processes
for use in mass spectrometry that guided us in a series of subsequent
discoveries, instrument developments, and commercialization. Vacuum matrix-assisted ionization on an intermediate pressure
matrix-assisted laser desorption/ionization source without the use of a laser, high voltages, or any other added energy was
simply unbelievable, at first. Individually and as a whole, the various
discoveries and inventions started to paint, inter alia, an exciting new picture and outlook in mass spectrometry from which
key developments grew that were at the time unimaginable, and continue
to surprise us in its simplistic preeminence. We, and others, have
demonstrated exceptional analytical utility. Our current research
is focused on how best to understand, improve, and use these novel
ionization processes through dedicated platforms and source developments.
These ionization processes convert volatile and nonvolatile compounds
from solid or liquid matrixes into gas-phase ions for analysis by
mass spectrometry using, e.g., mass-selected fragmentation
and ion mobility spectrometry to provide accurate, and sometimes improved,
mass and drift time resolution. The combination of research and discoveries
demonstrated multiple advantages of the new ionization processes and
established the basis of the successes that lead to the Biemann Medal
and this Perspective. How the new ionization processes relate to traditional
ionization is also presented, as well as how these technologies can
be utilized in tandem through instrument modification and implementation
to increase coverage of complex materials through complementary strengths.