'On-the-Fly' Gas-Phase Derivatization via Ion/Molecule Reactions: A Novel Strategy for Rapid Analysis of Epoxide Impurities in Active Pharmaceutical Ingredients

摘要

Epoxides can efficiently undergo gas-phase Meerwein reaction with ethylnitrilium ion (protonated acetonitrile). DFT calculations at the B3LYP/6-311+G(d,p) level show that the energetics of the gas-phase Meerwein is thermodynamically favorable. The gas-phase Meerwein reaction of epoxides with ethylnitrilium ion not only provides a means for structural identification but also offers a novel 'on-the-fly' approach for the direct LC-MS analysis of trace epoxide pharmaceutical impurities that are of genotoxic concern.