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Hit esc to quit hit any key to continue A New Forensics Technique to Investigate the Presence of Chemical FingerPrints in Human Breath.

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Presentation on theme: "Hit esc to quit hit any key to continue A New Forensics Technique to Investigate the Presence of Chemical FingerPrints in Human Breath."— Presentation transcript:

1 hit esc to quit hit any key to continue A New Forensics Technique to Investigate the Presence of Chemical FingerPrints in Human Breath

2 hit esc to quit hit any key to continue Objectives 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

3 hit esc to quit hit any key to continue Analyzing Volatile Organic Compounds in Breath Clinical Diagnosis –Elevated Organic Compounds –Isotopic Labeling Occupational Exposure Assessment Law Enforcement –Non-Invasive Monitoring for Drugs of Abuse –Breath Fingerprinting

4 hit esc to quit hit any key to continue 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. Chemicals in Human Breath as Forensic Tracers

5 hit esc to quit hit any key to continue Requirements of Breath Testing Application Breath Sampling System Inert chemical storage device Effective (automated) analytical inlet system and GC/MS Multi-sampler decontamination system

6 hit esc to quit hit any key to continue Selection of Sampling Device 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

7 hit esc to quit hit any key to continue Silonite TM 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 hit esc to quit hit any key to continue 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 Collecting Breath Samples into MiniCans Breath Sampler Prototype

9 hit esc to quit hit any key to continue 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 hit esc to quit hit any key to continue 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 hit esc to quit hit any key to continue Low Volume Breath Sampler

12 hit esc to quit hit any key to continue Laboratory Analysis HP 5973 GCMS L Stage Preconcentrator 7032L 21-Position MiniCan Autosampler 4600 Multi-Channel Standards Diluter

13 hit esc to quit hit any key to continue GC MS 6 Split Ctrl. VOC Breath Analyzer L SL I/O

14 hit esc to quit hit any key to continue CO2 and Water Elimination using Microscale Purge and Trap TM Internal Standard Calibration Standard Sample Glass BeadsTenax Cryogen in CO2 Focuser To GC VOCs H2O Helium PUMPMFC Helium Carrier Removing Water and CO2

15 hit esc to quit hit any key to continue 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 hit esc to quit hit any key to continue Testing Respiratory Adsorption and Desorption of VOCs 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

17 hit esc to quit hit any key to continue Tracer Chemicals Released Into Room for 8 Hour Exposure 1. Hexane 2. 1,4-Dioxane 3. Methyl Methacrylate 4. n-Butyl Acetate 5. 1,3,5-Trimethyl Benzene IS1 IS2 Sur1 IS3 Sur2

18 hit esc to quit hit any key to continue Chromatogram of Breath At Time=0 Hours

19 hit esc to quit hit any key to continue Chromatogram of Breath At Time=8 Hours

20 hit esc to quit hit any key to continue Single Ion Chromatogram of 1,3,5-Trimethylbenzene in Breath after 8 Hour Exposure

21 hit esc to quit hit any key to continue Recovery of Chemicals in Breath

22 hit esc to quit hit any key to continue 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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