Real-time Measurements of Volatile Organic Compounds with pptv Sensitivity

1. Real-time Measurements of Volatile Organic Compounds with pptv Sensitivity Dr. Todd Rogers Dr. Jim Conca Larry Lockrem Assistant Professor Dr. Joe Sears L&L Geochemical Services Columbia Basin College RJ Lee Group Kennewick, Washington Pasco, Washington Pasco, Washington

2. Post 9/11, Deepwater Horizon and Katrina clean-up • Air Force F-16 engine maintenance • Nuclear waste lab management • Public-Private partnerships with higher education Columbia Basin College Center for Laboratory Sciences

3. IN-SITU and Mobile Capabilities • Non Destructive Assay • Lab On-A-Cart • Radioactive Contamination Mapping System • Sensor Development • Radionuclide Logging System • Mossbauer Spectroscopy • Hot Cell Screening Probe • Fiber Optic Detector • VOC mapping with PTR-MS Mars

4. Proton Transfer Reaction Mass Spectrometry (PTR-MS) • Reliably detects hundreds of VOC, including BTEX, TCE, PCE, explosives and biogenics • Time resolutions as fast as 1 second have sensitivities in the pptv range. Time resolution of a minute approach ppqv range for some compounds. • No sample preparation is required • Can be operated while the van is moving • Time resolution, sensitivity and mobility opens the door to many unique applications • Environmental monitoring • Worker/public safety • Medical diagnosis (breath) • Food and wine industry • Atmospheric research • Litigation support

5. Chemical Ionization based technique, H3O+ is typically the reagent ion • Provides responses to compounds with proton affinities greater than that of H2O

6. What does the PTR-MS Measure? Anything above the red line with H3O+ Anything above the blue line with NO+ PCE TCE

7. Strengths • Time resolution: Up to one second, often operated at one or two minute time resolution to improve limits of detection • No sample preparation: No need to preconcentrate samples • It is possible to quantify compounds directly from ion signals without calibration • In situ analysis: Instrument can go in the field • Stand alone: No operator needed for fixed site applications • Weaknesses • Depletion of H3O+: If the sample contains one compound in extreme excess it will deplete the reagent ions • Some compounds are not ionized and are not seen • Qualitative analysis is difficult due to isobaric issues

8. Example PTR-MS signal Background spectrum 37 32 55 21 cis-3-hexenol 83 59

9. 1000 fold dilution of auto exhaust during a cold start • Mass assignments were determined using GC-MS data

10. Inter-comparison of benzene and toluene measurements made by three different methods at the same fixed site location in Mexico City. • Time response of GC-FID was 1 hour • Time response of DOAS was 5 minutes • Time response of PTR-MS was 1 minute • The fast time response of the PTR-MS shows sensitivity to local sources.

11. On-road Vehicle Emissions Example vehicle chase data for a) a gasoline vehicle without an operational catalytic converter, b) a gasoline vehicle with an operational catalytic converter and c) a heavy duty diesel bus. Toluene and CO2 correlation scatter plots for the shaded plumes above. Emission ratios are evaluated from the slopes.

12. Source Location and Mapping Map of an ethyl acetate plume that was mapped in approximately 15 minutes and shown graphically using on-board GPS data. Higher concentrations are shown using colors towards the red end of the visible spectrum. The prevailing winds on this day were west to east.

13. DC-8 Aircraft Exhaust VOC are observed at thrusts below 30% but below detection limits at higher thrusts

14. PTR-MS for Real-Time COPC Monitoringat Hanford • Recent technology innovations permit detection of all COPCs in the statement of work at the IH DL • Multiple inlet lines with switchable source monitoring to address worker safety in the tank farm • Interface an alarm system to the PTR-MS that can be triggered by real-time response to preset thresholds for various compounds 1. Warn workers of potential unsafe conditions 2. Trigger specific secondary samplers for off-line sampling and analysis

15. Hanford Tank Farm Application • Compounds of Potential Concern: • nitrosamines • furans • nitriles • aromatics • carbonyls • alcohols • ketones • amines • Investigating the performance of real-time field monitoring at the farms to compliment and assist air sampling using GC-MS

16. Results Target Ions and Limits of Detection - Nitrosamines and Furans

17. Results Target Ions and Limits of Detection - Nitriles and Aromatics

18. Results Target Ions and Limits of Detection - Alcohols, Carbonyls, others

19. Concluding thoughts • PTR-MS is a unique tool for making very fast measurements and will be more and more visible in the science world over the next few decades, particularly in environmental and health fields • RJ Lee has initiated the creation of an ASTM method for PTR-MS analysis of VOC • The mobile van is operational and is primarily scheduled for field work in environmental monitoring and contaminated site evaluation • RJ Lee Group will soon have a second instrument for additional projects • The van is here today, please stop by to take a look first hand • Feel free to contact me with any questions, comments or ideas at trogers@columbiabasin.edu Acknowledgements Jacob McCoskey, WSU/WRPS Nichole Wetle, CBC/RJ Lee Len Pingel, RJ Lee Dr. BerkKnighton, MSU Dr. Scott Herndon, ARI Dr. Mario Molina, MIT