Helium droplet mass spectrometry (HDMS)

Abstract

A method and device for mass spectrometry analysis, wherein a mass spectrometer is adapted for use with helium droplets, as an ionization site medium, with a proton being initially captured by a large helium droplet (˜10,000 helium atoms) and then cooled evaporatively to 0.4 Kelvin. The protonated helium droplet then picks up a neutral molecule of interest and the neutral molecule is protonated inside of the droplet with the liquid helium droplet acting as a heat bath to provide rapid cooling of the newly formed protonated molecule. As a result, there is essentially no energy available, at 0.4 Kelvin, for the protonated molecule to fragment. Remaining liquid helium is removed and the stably maintained protonated molecule is detected by a mass spectrometer. Since the molecules do not fragment when protonated (ionized), each compound in a mixture analyses gives one mass and the number of ions of a particular mass detected is directly proportional to the molar percentage of that mass in the sample. The device for effecting the method, comprises the elements of: (1) Helium cluster or droplet source; (2) Proton source for introduction of protons to the droplet (i.e., ionization); (3) atmospheric pressure (AP) Source for reduction of pressure to form a low pressure stream; (4) Cell pick-up elements where compound molecules are protonated or ionized at low temperature; (5) Desolvation area for removal of residual helium; and (6) Mass spectrometer and detector.

Dependencies are inferred from the claim text.