Method and device for non-contact sampling and detection

A method for the non-contact detection and analysis of analyte compounds that are located on a surface in an unconfined space, comprising:

• passing a first gas that is selected from the group consisting of helium and argon through an electrical discharge to produce charged and energetic molecular gas species;
• removing the positive and/or negative charged ionic particles from the gas;
• mixing said first gas with a second gas, said second gas being reactive with the charged and/or energetic gas species of said first gas to produce reactant ions of said second gas;
• focusing the reactant ions contained in the mixed gas stream to form a beam;
• directing the beam and the mixed gas stream into the unconfined space and onto said surface to react with analyte molecules and to form analyte ions by transferring energy from reactant ions to analyte molecules;
• and
• collecting at least a portion of the gas from the unconfined space, said collected portion containing analyte ions, and passing it into a differential mobility spectrometer to identify and quantify the analyte.

An ion production device comprising:

• An elongated containment means having an inlet for the introduction of a first gas at an upstream end thereof, and exit for an ion and gas stream at a downstream end thereof, and an inlet for the introduction of a second gas located intermediate the upstream and downstream ends;
• electrical discharge means positioned at the upstream end, said discharge means and first gas inlet means arranged to cause flow of the first gas though said discharge;
• electrode means to remove positive and/or negative ions generated by passage of said first gas through the electrical discharge, said means positioned downstream from said discharge means but upstream from said second gas entry;
• a mixing and reaction space downstream of said second gas entry, said space arranged to allow mixing of said first and second gas streams and to allow reaction of charged and/or energetic species remaining in said first gas with said second gas to produce reactant ions;
• at least one focusing and accelerating electrode located downstream of said mixing and reaction space, said electrode arranged to urge the reactant ions into a generally conical beam;
• and
• means to cause said ion beam together with said mixed gases to issue from the containment means through said exit.

A method for producing ions of analyte materials, comprising:

• passing a first gas stream through an electrical discharge to produce ions and energetic species of said gas;
• removing positive and/or negative ions produced by the electrical discharge from the gas stream leaving the energetic species;
• mixing the first gas stream with a second gas that has an ionization potential less than the ionization potential of said energetic species thereby producing reactant ions of said second gas, said reactant ions having ionization potentials greater than the ionization potentials of said analyte materials;
• focusing and accelerating said reactant ions to form a reactant ion beam within a flowing gas stream;
• directing said gas stream and ion beam into contact with said analyte materials;
• and
• forming analyte ions by transferring energy from reactant ions in said ion beam to the analyte material.

A device for the non-contact detection and analysis of analyte materials that are located in an unconfined space, comprising:

• an ion source including a containment means having an upstream end and a downstream end;
• an inlet for a first gas disposed at the upstream end of the containment means, an exit port at the downstream end, and an inlet for a second gas disposed intermediate the containment means ends;
• electrical discharge means positioned at the upstream end, said discharge means and first gas inlet arranged to cause flow of the first gas through said discharge;
• a mixing and reaction space downstream of the second gas inlet, said space arranged to allow mixing of said first gas and said second gas and to allow reaction of charged and/or energetic species, resulting from passage of said first gas through the electrical discharge, with said second gas to produce reactant ions;
• focusing and accelerating electrode means disposed downstream of said mixing and reaction space, said electrode means arranged to urge the reactant ions into a coherent beam;
• means at said exit port to direct said ion beam into contact with analyte materials in said unconfined space to thereby form sample analyte ions by transferring energy from reactant ions in said ion beam to analyte materials;
• and
• an ion collection means and a sensor operably connected to said ion source, said ion collection means having inlet port means arranged relative to the exit port of said ion source to collect at least a portion of the sample analyte ions and said sensor including means to identify and quantify the analyte material.