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Detection of (H2O)n+• and Н+(Н2О)n Cluster Ions Formed as a Result of Atmospheric Pressure Photoionization of Mixtures of Water Vapor with Aromatic Hydrocarbons in Heliumстатья
Информация о цитировании статьи получена из
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Дата последнего поиска статьи во внешних источниках: 26 января 2022 г.
- Авторы: Yashin Yu S., Revelsky I.A.
- Журнал: Journal of Analytical Chemistry
- Том: 76
- Номер: 13
- Год издания: 2021
- Издательство: Maik Nauka/Interperiodica Publishing
- Местоположение издательства: Russian Federation
- Первая страница: 1563
- Последняя страница: 1565
- DOI: 10.1134/s1061934821130141
- Аннотация: Earlier atmospheric pressure ionization massspectrometry was used to study water cluster ions formed in mixtures of water vapor with helium or nitrogen [1]. Ionization was performed by β-particles from a 63Ni source, the energy of which was about 60 keV. Studies were conducted at the temperature of the ion source 30–300°C and the concentration of water vapor in helium from 0.01 to about 3 vol %. At the temperature of the ion source 30°C and the concentration of water vapor about 3%, the recorded mass spectra contained peaks of water cluster ions (H2O and H+(H2O)n (n varied from 5 to 22). With the reduction of the concentration of water vapor, the intensity of the peaks of ions corresponding to the (H2O clusters decreased, and that for the H+(H2O)n clusters, increased. At the concentration of water vapor about 0.01%, the main peaks in the mass ranges corresponded to protonated clusters H+(H2O)n (n = 4). With an increase in the temperature of the ion source to 250–300°C, peaks of cluster ions (H2O were not detected the in mass spectra in the whole range of the studied concentrations of water vapor. It is known that atmospheric pressure photoionization mass spectrometry (APPI MS) proposed by us in [2, 3] for the majority of the studied analytes ensures the registration of mass spectra consisting only of peaks of molecular ions , protonated molecules MH+, or of both types. For some analytes, the corresponding mass spectra consisted only of (M–H)+ or (2M+H)+ ions. In most cases, an APPI ion source was combined with a gas chromatograph (carrier gas helium of the purity 99.999%). Photoionization was performed using an UV-lamp with the maximum energy of photons 10.6 eV. Helium and analytes were free fromwater; therefore, the corresponding mass spectra contained no peaks of water cluster ions. However, in HPLC/APPI MS, in which a water/acetonitrile mixture was used as an eluent and toluene was added as a dopant, the mass spectra of a mixture contained such peaks of water cluster ions as M(H2O)H+ and 2M(H2O)H+, where M was an acetonitrile molecule [4, 5]. The aim of our work was the study of water cluster ions formed in mixtures of water vapor with aromatic hydrocarbons in helium in the GC/APPI MS mode.
- Добавил в систему: Ревельский Игорь Александрович