Glyoxal measurement with a proton transfer reaction time of flight mass spectrometer (PTR‐TOF‐MS): characterization and calibration

We examine the potential for PTR‐TOF‐MS systems to quantitatively measure glyoxal in ambient air by characterizing the response of the instrument to a dilute glyoxal sample, calibrating the system as a function of humidity. The concentration of glyoxal in a sample air‐stream was measured with an UV absorption spectrometer in parallel to a PTR‐TOF‐MS. This calibration demonstrated that the PTR‐TOF‐MS has a relatively low sensitivity to glyoxal particularly at high humidity. Extensive fragmentation of glyoxal to formaldehyde was observed. This behaviour not only desensitizes PTR‐MS system to glyoxal; it may also pose a problem to the quantification of formaldehyde. © 2016 The Authors. Journal of Mass Spectrometry Published by John Wiley & Sons Ltd.