Detection of molecular ions of fluorine compounds by GC/FI-TOFMS
MSTips No. 088
Chlorofluorocarbon (CFC) and hydrochlorofluorocarbon (HCFC) have been used extensively as solvent, cleaning agent and foaming agent. Unfortunately CFC and HCFC have negative effects on the environment like ozone depletion and global warming. For this reason, CFC’s substitutes, such a hydrofluorocarbon (HFC) and hydrofluorocarbon ether (HFE), have been developed. In general, fluorine compounds are analyzed by gas chromatography (GC) / mass spectrometry (MS). However, molecular ions of these compounds are often not observed with electron ionization (EI) and chemical ionization (CI). Therefore, molecular weight determination is often difficult for unknown compounds when they are present as by-product or impurity. On the other hand, field ionization (FI) is a very soft ionization technique capable to observe the molecular ion of volatile compounds. This application note shows that FI is a suitable technique to determine the molecular weight of compounds which are not producing molecular ions in EI or CI.