Chemical ionization using CF3+: Efficient detection of small alkanes and fluorocarbons

The trifluoromethyl ion CF3+ is evaluated as a chemical ionization (CI) precursor in a compact Fourier Transform Ion Cyclotron Resonance (FTICR) mass spectrometer. It reacts with alkanes by hydride abstraction allowing characterization and quantification of alkanes up to C4 and cyclic. With larger alkanes fragmentation occurs. Fluorocarbons react by fluoride abstraction. Rate coefficients have been measured for reaction with alkanes, fluoroalkanes, chlorofluoroalkanes as well as several common VOCs. Use of CF3+ for trace analysis in air has been tested on an air sample containing traces of acetone, toluene, benzene and cyclohexane. The results are consistent with those obtained with H3O+ precursor and allow additional cyclohexane quantification.

Figure optionsDownload high-quality image (62 K)Download as PowerPoint slideResearch highlights▶ Small VOCs are detected and quantified with CF3+ chemical ionization in a FTICR. ▶ Unprotonable compounds such as alkanes and halocarbons react with CF3+. ▶ Alkanes and fluorocarbons react with CF3+ by hydride or fluoride abstraction. ▶ Trace analysis in air using CF3+ was performed on cyclohexane, an unprotonable VOC.