Reactive nitrogen and total organic carbon calibration techniques for the Aerodyne aerosol mass spectrometer

The Aerodyne aerosol mass spectrometer (AMS) is used extensively to measure the chemical composition of non-refractory submicron particles for laboratory and atmospheric field studies. Typical AMS calibration methods are mass-based, involving generating pure or mixtures with a known size number concentration. Here we present new method using heated platinum/molybdenum catalyst-based conversion technique that provides an independent measurement reactive nitrogen (Nr) total organic carbon (Cy) traceable gas-phase standards nitric oxide (NO) dioxide (CO2), respectively. was tested dried composed ammonium nitrate (AN), other salts, nitrogen-containing species. ionization efficiencies determined single particle Nr matched within experimental uncertainties (±15%). By measuring lens transmission efficiency incorporating light-scattering measurements collection efficiency, catalyst independently showed relative (RIE) essentially same among different containing compounds (±9%), regardless corresponding anion stoichiometry, quantifying support major assumption inherent in calibrations. Cy were calibrate RIE 4-nitrocatechol (1.1 ± 0.4), isosorbide mononitrate (1.2 0.1) triammonium citrate (2.1 0.2), which range RIEs quantitation. combined system provided more accurate elemental carbon-to-nitrogen ratios than high-resolution analysis Improved-Ambient plus inorganic nitrogen.