Are clusters important in understanding the mechanisms in atmospheric pressure ionization? Part 1: Reagent ion generation and chemical control of ion populations.
It is well documented since the early days of the development of atmospheric pressure ionization methods, which operate in the gas phase, that cluster ions are ubiquitous. This holds true for atmospheric pressure chemical ionization, as well as for more recent techniques, such as atmospheric pressure photoionization, direct analysis in real time, and many more. In fact, it is well established that cluster ions are the primary carriers of the net charge generated. Nevertheless, cluster ion chemistry has only been sporadically included in the numerous proposed ionization mechanisms leading to charged target analytes, which are often protonated molecules. This paper series, consisting of two parts, attempts to highlight the role of cluster ion chemistry with regard to the generation of analyte ions. In addition, the impact of the changing reaction matrix and the non-thermal collisions of ions en route from the atmospheric pressure ion source to the high vacuum analyzer region are discussed. This work addresses such issues as extent of protonation versus deuteration, the extent of analyte fragmentation, as well as highly variable ionization efficiencies, among others. In Part 1, the nature of the reagent ion generation is examined, as well as the extent of thermodynamic versus kinetic control of the resulting ion population entering the analyzer region.
Institute for Pure and Applied Mass Spectrometry, Physical and Theoretical Chemistry, University of Wuppertal, 42119, Wuppertal, Germany, s.klee@uni-wuppertal.de.
Sonja
S
Klee
Valerie
V
Derpmann
Walter
W
Wißdorf
Sebastian
S
Klopotowski
Hendrik
H
Kersten
Klaus J
KJ
Brockmann
Thorsten
T
Benter
Sascha
S
Albrecht
Andries P
AP
Bruins
Faezeh
F
Dousty
Tiina J
TJ
Kauppila
Risto
R
Kostiainen
Rob
R
O'Brien
Damon B
DB
Robb
Jack A
JA
Syage
D000390:Air Ionization / Q000528:radiation effects; D001274:Atmospheric Pressure; D055598:Chemical Phenomena / Q000187:drug effects; D007202:Indicators and Reagents / Q000737:chemistry / Q000528:radiation effects; D008027:Light; D008956:Models, Chemical; D055668:Photochemical Processes; D062211:Spatio-Temporal Analysis; D013816:Thermodynamics
D007202:Indicators and Reagents