Acetonitrile Ion Suppression in Atmospheric Pressure Ionization Mass Spectrometry

作者：Colizza Kevin; Mahoney Keira E; Yevdokimov Alexander V; Smith James L; Oxley Jimmie C^*

来源：Journal of the American Society for Mass Spectrometry, 2016, 27(11): 1796-1804.

DOI：10.1007/s13361-016-1466-1

• Acetonitrile ion suppression
• Peroxide detection
• Menadione
• TATP
• Energetic materials
• Gas phase reactions

Efforts to analyze trace levels of cyclic peroxides by liquid chromatography/mass spectrometry gave evidence that acetonitrile suppressed ion formation. Further investigations extended this discovery to ketones, linear peroxides, esters, and possibly many other types of compounds, including triazole and menadione. Direct ionization suppression caused by acetonitrile was observed for multiple adduct types in both electrospray ionization and atmospheric pressure chemical ionization. The addition of only 2% acetonitrile significantly decreased the sensitivity of analyte response. Efforts to identify the mechanism were made using various nitriles. The ion suppression was reduced by substitution of an acetonitrile hydrogen with an electron-withdrawing group, but was exacerbated by electron-donating or steric groups adjacent to the nitrile. Although current theory does not explain this phenomenon, we propose that polar interactions between the various functionalities and the nitrilemay be forming neutral aggregates thatmanifest as ionization suppression.

• 出版日期2016-11