Quaternary Amines Analysis by LCMS Finding the Right Ion - Tech Information
April 14, 2020
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Date: 14-APRIL-2020 Last Updated: 30-NOVEMBER-2025
LC-MS Analysis of Quaternary Amines: Key Considerations
LC-MS Analysis of Quaternary Amines: Key Considerations
When analyzing quaternary amines by LC-MS, remember that these compounds are permanently charged. Unlike tertiary amines, which typically appear in positive ion mode as [M + H]+, quaternary amines do not require protonation they are already ionized.
For accurate identification:
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In your extracted ion chromatograms (EICs), target the [M]+ ion rather than [M + H]+.
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Searching for [M + H]+ may yield no peak or a peak from an unrelated compound, since quaternary amines do not form this ion.
Following this approach helps ensure correct peak assignment and prevents misidentification of your analyte.