Details
| Originalsprache | Englisch |
|---|---|
| Aufsatznummer | e8998 |
| Fachzeitschrift | Rapid Communications in Mass Spectrometry |
| Jahrgang | 35 |
| Ausgabenummer | 4 |
| Frühes Online-Datum | 3 Nov. 2020 |
| Publikationsstatus | Veröffentlicht - 7 Jan. 2021 |
Abstract
Rationale: Ion mobility spectrometry (IMS) instruments are typically equipped with atmospheric pressure chemical ionization (APCI) sources operated at ambient pressure. However, classical APCI-IMS suffers from a limited ionization yield for nonpolar substances with low proton affinity (PA). This is mainly due to ion clustering processes, especially those that involve water molecules, inhibiting the ionization of these substances. Methods: High Kinetic Energy (HiKE)-IMS instruments are operated at decreased pressures and high reduced electric field strengths. As most clustering reactions are inhibited under these conditions, the ionization yield for nonpolar substances with low PA in HiKE-IMS should differ from that in classical APCI-IMS. To gain first insights into the ionization capabilities and limitations of HiKE-IMS, we investigated the ionization of four model substances with low PA in HiKE-IMS using HiKE-IMSMS as a function of the reduced electric field strength. Results: The four model substances all have proton affinities between those of H2O and (H2O)2 but exhibit different ionization energies, dipole moments, and polarizabilities. As expected, the results show that the ionization yield for these substances differs considerably at low reduced electric field strengths due to ion cluster formation. In contrast, at high reduced electric field strengths, all substances can be ionized via charge and/or proton transfer in HiKE-IMS. Conclusions: Considering the detection of polar substances with high PAs, classical ambient pressure IMS should reach better detection limits than HiKE-IMS. However, considering the detection of nonpolar substances with low PA that are not detected, or only difficult to detect, at ambient pressure, HiKE-IMS would be beneficial.
ASJC Scopus Sachgebiete
- Chemie (insg.)
- Analytische Chemie
- Chemie (insg.)
- Spektroskopie
- Chemie (insg.)
- Organische Chemie
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in: Rapid Communications in Mass Spectrometry, Jahrgang 35, Nr. 4, e8998, 07.01.2021.
Publikation: Beitrag in Fachzeitschrift › Artikel › Forschung › Peer-Review
}
TY - JOUR
T1 - Formation of positive product ions from substances with low proton affinity in high kinetic energy ion mobility spectrometry
AU - Allers, Maria
AU - Kirk, Ansgar T.
AU - Schaefer, Christoph
AU - Schlottmann, Florian
AU - Zimmermann, Stefan
N1 - Funding Information: The authors thank Airsense Analytics for providing the chemicals used in this work. This work was funded by the Deutsche Forschungsgemeinschaft (DFG, German Research Foundation), joint project BE 2124/8-1?ZI 1288/8-1. Open access funding enabled and organized by Projekt DEAL.
PY - 2021/1/7
Y1 - 2021/1/7
N2 - Rationale: Ion mobility spectrometry (IMS) instruments are typically equipped with atmospheric pressure chemical ionization (APCI) sources operated at ambient pressure. However, classical APCI-IMS suffers from a limited ionization yield for nonpolar substances with low proton affinity (PA). This is mainly due to ion clustering processes, especially those that involve water molecules, inhibiting the ionization of these substances. Methods: High Kinetic Energy (HiKE)-IMS instruments are operated at decreased pressures and high reduced electric field strengths. As most clustering reactions are inhibited under these conditions, the ionization yield for nonpolar substances with low PA in HiKE-IMS should differ from that in classical APCI-IMS. To gain first insights into the ionization capabilities and limitations of HiKE-IMS, we investigated the ionization of four model substances with low PA in HiKE-IMS using HiKE-IMSMS as a function of the reduced electric field strength. Results: The four model substances all have proton affinities between those of H2O and (H2O)2 but exhibit different ionization energies, dipole moments, and polarizabilities. As expected, the results show that the ionization yield for these substances differs considerably at low reduced electric field strengths due to ion cluster formation. In contrast, at high reduced electric field strengths, all substances can be ionized via charge and/or proton transfer in HiKE-IMS. Conclusions: Considering the detection of polar substances with high PAs, classical ambient pressure IMS should reach better detection limits than HiKE-IMS. However, considering the detection of nonpolar substances with low PA that are not detected, or only difficult to detect, at ambient pressure, HiKE-IMS would be beneficial.
AB - Rationale: Ion mobility spectrometry (IMS) instruments are typically equipped with atmospheric pressure chemical ionization (APCI) sources operated at ambient pressure. However, classical APCI-IMS suffers from a limited ionization yield for nonpolar substances with low proton affinity (PA). This is mainly due to ion clustering processes, especially those that involve water molecules, inhibiting the ionization of these substances. Methods: High Kinetic Energy (HiKE)-IMS instruments are operated at decreased pressures and high reduced electric field strengths. As most clustering reactions are inhibited under these conditions, the ionization yield for nonpolar substances with low PA in HiKE-IMS should differ from that in classical APCI-IMS. To gain first insights into the ionization capabilities and limitations of HiKE-IMS, we investigated the ionization of four model substances with low PA in HiKE-IMS using HiKE-IMSMS as a function of the reduced electric field strength. Results: The four model substances all have proton affinities between those of H2O and (H2O)2 but exhibit different ionization energies, dipole moments, and polarizabilities. As expected, the results show that the ionization yield for these substances differs considerably at low reduced electric field strengths due to ion cluster formation. In contrast, at high reduced electric field strengths, all substances can be ionized via charge and/or proton transfer in HiKE-IMS. Conclusions: Considering the detection of polar substances with high PAs, classical ambient pressure IMS should reach better detection limits than HiKE-IMS. However, considering the detection of nonpolar substances with low PA that are not detected, or only difficult to detect, at ambient pressure, HiKE-IMS would be beneficial.
UR - http://www.scopus.com/inward/record.url?scp=85100125753&partnerID=8YFLogxK
U2 - 10.1002/rcm.8998
DO - 10.1002/rcm.8998
M3 - Article
C2 - 33140479
AN - SCOPUS:85100125753
VL - 35
JO - Rapid Communications in Mass Spectrometry
JF - Rapid Communications in Mass Spectrometry
SN - 0951-4198
IS - 4
M1 - e8998
ER -