Flame sampling photoionization mass spectrometry of dichloroethenol

A newly developed flame-sampling laser-ionization mass spectrometer has been used for the detection of combustion intermediates in a low-pressure methane/oxygen flame seeded with trichloroethylene. Among the most prominent intermediates are 1,1-dichloroethylene and 2,2-dichloroethenol. Near-threshold photoionization efficiency curves, produced with a tunable vacuum ultraviolet (VUV) laser light source, are used for isomerically selective detection of these species. The previously unmeasured ionization potential for 2,2-dichloroethenol is placed at 9.09±0.02 eV.