Atmospheric-pressure-interface mass spectrometer for field measurements

High precision mass spectrometer with a chemical ionization inlet for the Institute for Atmospheric and Earth System Research of the University of Helsinki.

High precision mass spectrometer with a chemical ionization inlet for the Institute for Atmospheric and Earth System Research of the University of Helsinki. The analyzer must be capable of measuring both atmospheric trace gas concentrations at sub-ppt level and naturally charged ions. The instrument will be deployed in field measurements in a coastal environment. The instrument meets the following requirements: a) Resolving power > 8000 b) Chemical ionization (CI) inlet which allows 1. quantification of highly oxygenated organic molecules (HOM), sulphuric acid and inorganic iodine spe-cies including I2, iodine oxides and iodine oxoacids 2. measurements without ionization, in order to measure naturally charged ions 3. fast (< 1 min) and automated switching between the different modes of operation mentioned above 4. soft ionization and ion transmission, for measurements of ion clusters c) Detection limit of the device below 10^6 molecules/cm3 for 5 min integration time for gas-phase sulphuric acid, HOM species, I2 and HIO3. d) Measurement range minimum: 15 – 2000 Th e) Able to perform long-term ambient monitoring in field conditions. The instrument must run a minimum of two weeks at a time without maintenance. f) The instrument must be rack mounted, easily transportable and its overall weight should be < 250 kg. g) Manufacturer must provide comprehensive analysis and data acquisition software h) Bipolar voltage supply to be able to measure in both positive and negative polarity i) Able to sample air from atmospheric pressure through an electrically grounded inlet.