Patent ID: 9297785
Filing Date: 2016-03-29
CPC Classification: G01N,H01J

Claim Text:
1. A method to detect the presence of substances based primarily on the vapors they release to a surrounding gas, involving: a) sampling said gas to which said vapors have been released and passing it through a prefiltering stage including means configured for removing particles larger than 25 μm carried by said gas, b) passing said prefiltered gas into a vapor capture stage including a collection chamber containing a vapor collector, such that a fraction of said vapors are captured into said vapor collector, said vapors not captured into said vapor collector being residual vapors, c) where said vapor capture stage includes at least one contamination prevention means, such that said residual vapors having circulated through said collection chamber during one vapor capture event are not released to the vapor collector during a subsequent vapor capture event into said gas, and therefore are not captured by the vapor collector during said subsequent vapor capture event, and d) a desorption-ionization and analysis stage where said vapors captured into said vapor collector are thermally released into a flow of clean gas and passed through an ionization chamber where a fraction of said thermally released vapors are turned into ions, and said ions are finally analyzed and detected in an analytical instrument.