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A New Forensics Technique to Investigate the Presence of Chemical “FingerPrints” in Human Breath

A New Forensics Technique to Investigate the Presence of Chemical “FingerPrints” in Human Breath. Test Ability to Collect and Analyze Trace Level Chemicals in Human Breath Determine if Concentrations Increase upon Prolonged Exposure

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A New Forensics Technique to Investigate the Presence of Chemical “FingerPrints” in Human Breath

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  1. A New Forensics Technique to Investigate the Presence of Chemical “FingerPrints” in Human Breath

  2. Test Ability to Collect and Analyze Trace Level Chemicals in Human Breath Determine if Concentrations Increase upon Prolonged Exposure Determine Whether Trace Chemicals can be Detected in Breath Samples Days after the Initial Exposure Objectives

  3. Clinical Diagnosis Elevated Organic Compounds Isotopic Labeling Occupational Exposure Assessment Law Enforcement Non-Invasive Monitoring for Drugs of Abuse Breath Fingerprinting Analyzing Volatile Organic Compounds in Breath

  4. Chemicals in Human Breath as Forensic Tracers • The same mechanism that allows efficient transfer of O2 and CO2 through the alveoli also allows the exchange of other chemicals that are in the air as well • Once in the blood, chemicals may metabolize readily, or may dissolve into adipose tissue where they may release back into the blood over time, allowing them to be detected in exhaled breath.

  5. Breath Sampling System Inert chemical storage device Effective (automated) analytical inlet system and GC/MS Multi-sampler decontamination system Requirements of Breath Testing Application

  6. Choices: Tedlar bags, Adsorbent tubes, stainless steel canisters. Canisters advantages: Ease of sampling (self contained vacuum) Elimination of volume sampling errors Ability to recover reactive and thermally labile compounds Selection of Sampling Device

  7. SiloniteTM Coating Maximizes Inertness • Silonite coating provides a highly inert surface preventing surface reactions that can occur on stainless steel • Compounds that can be chromatographed can generally be stored in Silonite coated vessels.

  8. Collecting Breath Samples into MiniCans Breath Sampler Prototype Last 20-30% of Exhaled Breath is Captured in Tube The Breath Sample is Recovered into MiniCan without Introduction of Room Air Breath Sampler Volume - 650cc MiniCan Volume - 380cc

  9. 2-Step Breath Sampling Procedure 1. Blow through disposable, check-valve to flush 0.65L tube volume 2. Connect evacuated MiniCan to recover breath sample

  10. Validating Proper Sampling of Breath • Tetrafluoroethane released into room • Participant inhales outside of room, walks into room and exhales through sampler • Sampled breath introduced into can • Second MiniCan filled with room air for comparison

  11. Low Volume Breath Sampler

  12. Laboratory Analysis HP 5973 GCMS 7100 7032L 4600 7100 3-Stage Preconcentrator 7032L 21-Position MiniCan Autosampler 4600 Multi-Channel Standards Diluter

  13. VOC Breath Analyzer SL I/O SL I/O 6 Split Ctrl. GC MS 7100 7032-L

  14. CO2 and Water Elimination using Microscale Purge and TrapTM MFC PUMP Removing Water and CO2 CO2 Helium Carrier Helium To GC H2O VOCs Focuser Glass Beads Tenax Internal Standard Calibration Standard Sample Cryogen in

  15. Decontamination System Allowing Unlimited Reuse of MiniCans • Cleans MiniCans by Filling and Evacuating with Humidified Nitrogen. • Testing one MiniCan after Cleaning Certifies all 21

  16. Test Breath at t=0 Expose Participant to chemicals at less than 5% of OSHA PELs for 8 hours Use personal MiniCan sampler (IH1200) to simultaneously collect air representative of what the participant is breathing Test participants breath at the end of the day Test participants breath on subsequent days Testing Respiratory Adsorption and Desorption of VOCs

  17. Tracer Chemicals Released IntoRoom for 8 Hour Exposure 1. Hexane 2. 1,4-Dioxane 3. Methyl Methacrylate 4. n-Butyl Acetate 5. 1,3,5-Trimethyl Benzene Sur2 IS3 5 Sur1 IS2 1 3 IS1 4 2

  18. Chromatogram of Breath At Time=0 Hours 2 1 4 5

  19. Chromatogram of Breath At Time=8 Hours

  20. Single Ion Chromatogram of 1,3,5-Trimethylbenzene in Breath after 8 Hour Exposure

  21. Recovery of Chemicals in Breath

  22. Conclusion • Analytical methodology has been developed which allows VOCs in human breath to be measured down to part-per-trillion levels • Factors other than exposure levels appear to play a part in the concentration and lifetime of VOCs recovered in breath samples • For this technique to be a practical forensics tool, the list of tracer chemicals would have to be somewhat unique. This may be the case in certain illegal drug manufacturing operations, although studies will have to be performed to substantiate this.

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