Juergen O. Metzger et.al.: Electrospray ionization and atmospheric pressure
ionization mass spectrometry of stable organic radicals
- Author(s): Juergen O. Metzger, Jens Griep-Raming
- Title: Electrospray ionization and atmospheric pressure ionization mass
spectrometry of stable organic radicals
- Date of Upload: 1999
- Article: Eur. J. Mass Spectrom. 5, 157 - 163 (1999), Department of
Chemistry, University of Oldenburg, Carl-von-Ossietzky-Str. 9-11, 26129
Oldenburg, Germany;
- Keywords: electrospray ionization, atmospheric pressure chemical
ionization, stable radicals, ESI-MS, mass spectrometry, reactive intermediate,
reaction, solution
- Abstract:
- The ionization behavior of stable radicals (1–8) was studied under electrospray
ionization (ESI) and atmospheric pressure ionization (APCI) conditions. With
APCI, using methanol + water as the solvent, most radicals were protonated
to give the radical cation [M + 1]+·, whereas TEMPO (5) was detected
as the M+ ion and galvinoxyl (1) gave the [M + 2]+ ion.
Using benzene as the solvent, all radicals (1–8) were efficiently oxidized
to give M+ as the base peak. Under ESI conditions using methanol
+ water with 1% acetic acid, stable radicals (5–7) gave [M + 1]+·
, (2–4) M+ , whereas (1) and (8) showed the [M + 2]+
ion as the base peak. Using the ESI source as a controlled-current electrolytic
cell, radicals (2–8) were efficiently oxidized to give M+ ions.
Radical (1) was detected as the [M + 2]+ ion. Detection limits
for the radicals (1–8) were between 3 x 10-9 mol L-1 and 5 x 10-7 mol L-1
using APCI or ESI in the full-scan mode. In most cases detection limits were
lower using the tandem mass spectrometry (MS/MS) full-scan mode.
- URL: http://www.chemie.uni-oldenburg.de/oc/metzger/publikationen/pdf/82.pdf
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