Determination of trace compounds and artifacts in nitrogen background measurements by proton transfer reaction time-of-flight mass spectrometry under dry and humid conditions.

A qualitative analysis was applied for the determination of trace compounds at the parts per trillion in volume (ppt ) level in the mass spectra of nitrogen of different qualities (5.0 and 6.0) under dry and humid conditions.

Elucidation of artefacts in proton transfer reaction time-of-flight mass spectrometers.

We present an effective procedure to differentiate instrumental artefacts, such as parasitic ions, memory effects, and real trace impurities contained in inert gases. Three different proton transfer reaction mass spectrometers were used in order to identify instrument-specific parasitic ions. The methodology reveals new nitrogen- and metal-containing ions that up to date have not been reported.