Since many years PTR-MS is a well established technique in trace gas analysis with its major advantages of having very short response times of below 100ms and outstanding detection limits in the single digit pptv region. However, the quadrupole mass filter based instruments used so far cannot separate isobaric compounds due to lack of mass resolution. To overcome this problem Ionicon developed the so called PTR-TOF 8000 instrument, which couples the well established PTR ionization technique with a high resolution time-of-flight (TOF) mass analyzer. In contrast to a quadrupole based PTR-MS where only one nominal mass at a time can be monitored, the PTR-TOF acquires whole mass spectra in split-seconds at a resolution of up to 8.000 m/{delta}m (FWHM). As there might be applications where an enormous mass resolution is not necessarily needed, but the sensitivity has to be as high as possible, we now developed an instrument (called PTR-TOF 2000) that performs with an enhanced sensitivity at the expense of a somewhat lower mass resolution.

Proton transfer reaction-mass spectrometry (PTR-MS) offers many advantages for trace gas analysis, including no sample preparation, real-time analysis, high selectivity and sensitivity, ultra-low detection limits and very short response times. These characteristic features have made it an ideal tool for many applications in science, technology and society. Here we will discuss recent developments, in particular advances concerning sensitivity, selectivity and general applicability.