Soft X-ray Atmospheric Pressure Photoionization in Liquid Chromatography–Mass Spectrometry
| Autor: | Mikko Sipilä, Roope Vesander, Nina Sarnela, Risto Kostiainen, Juha-Pekka Hieta |
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| Přispěvatelé: | Division of Pharmaceutical Chemistry and Technology, Institute for Atmospheric and Earth System Research (INAR), Drug Research Program, Pharmaceutical Spectroscopy and Imaging |
| Rok vydání: | 2021 |
| Předmět: |
010504 meteorology & atmospheric sciences
Proton Astrophysics::High Energy Astrophysical Phenomena Analytical chemistry Photoionization Mass spectrometry 114 Physical sciences 01 natural sciences 7. Clean energy Mass Spectrometry Analytical Chemistry Ion Ionization Electron affinity Physics::Atomic and Molecular Clusters Technical Note 0105 earth and related environmental sciences Ions Atmospheric pressure Chemistry X-Rays 010401 analytical chemistry 0104 chemical sciences Atmospheric Pressure 317 Pharmacy Valence electron Chromatography Liquid |
| Zdroj: | Analytical Chemistry |
| ISSN: | 0003-2700 |
| DOI: | 10.1021/acs.analchem.1c01127 |
| Popis: | Soft X-ray atmospheric pressure photoionization (soft X-ray APPI) as an ionization method in liquid chromatography-mass spectrometry (LC-MS) is presented. The ionization mechanism was examined with selected test compounds in the negative ion mode, using soft X-ray APPI source emitting 4.9 keV photons. Test compounds with an acidic group were ionized by a proton transfer reaction, producing deprotonated molecules ([M-H](-)), whereas compounds having positive electron affinity were ionized by a charge exchange reaction, producing negative molecular ions (M-.). Soft X-ray APPI does not require a dopant to achieve high ionization efficiency, which is an advantage compared with vacuum ultraviolet APPI with 10 eV photons, in which a dopant is needed to improve ionization efficiency. The energy of the soft X-ray photons is in the keV range, which is high enough to displace a valence electron and often also inner shell electrons from LC eluents and atmospheric gases, initiating an efficient ionization process in the negative ion mode. |
| Databáze: | OpenAIRE |
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