Chemical ionization mass spectrometry of hydrofluorocarbons, hydrofluorocarbon ethers and perfluoroalkenes

Positive and negative chemical ionization (CI) mass spectrometry is studied for hydrofluorocarbons (HFCs), hydrofluorocarbon ethers (HFEs), and perfluoroalkenes (PFCs) using various kinds of reagent gas. While no quasi-molecular ion was observed under electron impact ionization for saturated MFCs, M-F]⁺ is detected under CI conditions using methane as a reagent gas. Mechanisms for the generation of M-F]⁺ are discussed. Furthermore, nitrogen monoxide can be used as a reagent gas to observe M + NO]⁺ for many HFCs and HFEs. In negative mode chloroform is also available to generate M + Cl]⁻ for HFCs and HFEs containing -CHF- groups.