Patent ID: 9121844
Filing Date: 2015-09-01
Classification: G01N

Abstract:
1. A method to analyze metabolites released by at least one organism, said method including the following steps: sampling into an ionizer containing anions a sample flow of gas after bringing it in contact with said at least one organism, such that said gas carries sample vapors released by said at least one organism, said ionizer converting at least some of said sample vapors into negative ions by transfer of charge between said anions and molecules of said vapors; introducing said ions into an analytical instrument having an atmospheric pressure ion source to determine relative ion abundances; determining from said relative ion abundances a sample list of relative abundances for a pre-established group of metabolite ions; sampling into an ionizer a background flow of said gas without bringing it in contact with said at least one organism, said gas carrying background vapors, said ionizer converting at least some of said background vapors into background ions; determining a background list of relative abundances, based on said background ions, for said pre-established group of metabolite ions when said gas carrying said background vapors is ingested by said analytical instrument; and determining a background-corrected list of relative abundances for said pre-established group of metabolite ions by subtracting said background list from said sample list, wherein, said analytical instrument includes either a differential mobility analyzer or a mass spectrometer, wherein, said sample vapors are not prepared prior to being sampled into said ionizer, and, wherein, at least one among said background flow of said gas and said sample flow of said gas are humidified prior to being sampled into said ionizer.