TY - JOUR
T1 - Surface ionization mass spectrometry of drugs in the thermal and hyperthermal energy range - a comparative study
AU - Dagan, Shai
AU - Amirav, Aviv
AU - Fujü, Toshihiro
N1 - Funding Information:
This work was supported by a grant from the German-Israeli Foundation for Scientific Research and Development, and by the Japanese Science and Technology Agency under the framework of Japan-Israel cooperative scientific agreements (project No. 49).
PY - 1995/12/15
Y1 - 1995/12/15
N2 - Thermal and hyperthermal surface ionization (SI) mass spectra of nicotine, caffeine and lidocaine were obtained using a rhenium oxide surface. Thermal surface ionization was studied on an oxidized surface positioned inside an electron impact ion source, while hyperthermal surface ionization (HSI) was obtained upon seeding the compounds into a hydrogen or helium supersonic molecular beam that scattered from the rhenium oxide surface. Both HSI and SI provide rich, informative and complementary mass spectral information. The results indicate that SI follows thermal dissociation processes on the surface prior to the desorption of the ion, while in HSI no thermal equilibrium is established and the ionization process is impulsive, followed by mostly unimolecular ion dissociation. HSI mass spectra are similar to electron impact mass spectra in the fragment ion masses, but the observed relative intensities are different. HSI is a softer ionization method compared to SI, and enables the degree of ion fragmentation to be tuned so that it can be minimized to a low level at low molecular kinetic energy. In SI, limited control over the degree of fragmentation is possible through the surface temperature. The analytical mass spectrometric applications of SI and HSI are briefly mentioned.
AB - Thermal and hyperthermal surface ionization (SI) mass spectra of nicotine, caffeine and lidocaine were obtained using a rhenium oxide surface. Thermal surface ionization was studied on an oxidized surface positioned inside an electron impact ion source, while hyperthermal surface ionization (HSI) was obtained upon seeding the compounds into a hydrogen or helium supersonic molecular beam that scattered from the rhenium oxide surface. Both HSI and SI provide rich, informative and complementary mass spectral information. The results indicate that SI follows thermal dissociation processes on the surface prior to the desorption of the ion, while in HSI no thermal equilibrium is established and the ionization process is impulsive, followed by mostly unimolecular ion dissociation. HSI mass spectra are similar to electron impact mass spectra in the fragment ion masses, but the observed relative intensities are different. HSI is a softer ionization method compared to SI, and enables the degree of ion fragmentation to be tuned so that it can be minimized to a low level at low molecular kinetic energy. In SI, limited control over the degree of fragmentation is possible through the surface temperature. The analytical mass spectrometric applications of SI and HSI are briefly mentioned.
KW - Hyperthermal surface ionization
KW - Surface ionization
UR - http://www.scopus.com/inward/record.url?scp=0001594303&partnerID=8YFLogxK
U2 - 10.1016/0168-1176(95)04321-7
DO - 10.1016/0168-1176(95)04321-7
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AN - SCOPUS:0001594303
SN - 0168-1176
VL - 151
SP - 159
EP - 165
JO - International Journal of Mass Spectrometry and Ion Processes
JF - International Journal of Mass Spectrometry and Ion Processes
IS - 2-3
ER -