A hollow cathode proton transfer reaction time of flight mass spectrometer

A proton transfer reaction mass spectrometer has been developed that couples a readily portable hollow cathode proton transfer reaction cell with a reflectron time of flight detector (PTR-ToF). The instrument is capable of detection of trace gas components as low as 1 ppbv on a timescale of between 10 and 60 s and with a sensitivity of 3.7 ncps ppbv−1 (normalised counts per second per parts per billion by volume) for toluene and 28  ncps ppbv−1 for acetone. The PTR-ToF instrument developed is capable of high mass resolution, high mass accuracy (∼300 ppm) and multiplexed spectral acquisition, leading to rapid and selective online analysis of trace components in complex gas mixtures. Attention to the materials chemistry of the system and the reaction conditions in the PTR cell are expected to enable the detection limit of this instrument to be lowered and the sensitivity enhanced.