JMSSJ On-line

JMSSJ On-line, Vol. 48 (2000) No. 1, pp. 47-55

Effects of Solvents, Matrices, and of Reagents for Producing Adduct Ions on Liquid Ionization Mass Spectra of Monocyclic Hydrocarbon Hydroperoxides		>> Full Text PDF >> References
*Yoshiyuki MOCHIDA^a), Gorou ARAI^a), Shigeo NAKAMURA^a), and Masahiko TSUCHIYA^b)** ^a) Department of Applied Chemistry, Faculty of Engineering, Kanagawa University (3-27-1, Rokkaku-bashi, Kanagawaku, Yokohama 221-8686, Japan)* ^b) Present address: 4-37-27 Kugayama, Suginami-ku, Tokyo 168-0082, Japan

Mass spectra of hydroperoxides, such as cumen hydroperoxide (CHP), diisopropylbenzene hydroperoxide (DBH), p-mentane hydroperoxide (PMH) were investigated by liquid ionization (LPI) mass spectrometry. Hydrated molecular ions [M+H+nH₂O]⁺, n=1-10, were dominant in LPI mass spectra of all samples when they were dissolved simply in a solvent, although ethanol was a good solvent. When ethanol was used with butanol (1-3%), i.e., a mixed solvent, and/or with acetone, which was evaporated in the ionization chamber (as a vapor matrix), those hydrated ions were suppressed and [M+H]⁺ of PMH became the base peak. Acetone is a useful vapor matrix for obtaining [M+H]⁺. When pyridine (Py, 3-8%)-ethanol mixture was used as a solvent, molecular adduct ions [M+H+Py]⁺ became dominant for CHP and DBH. LPI-MS is useful not only for determining molecular weights of hydroperoxides but also for investigating the solvation and effects of various kinds of additives.

Key words: Liquid ionization mass spectrometry, Hydroperoxides, Adduct ion, Matrix, Hydrated ions

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