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Cwa Invited Talk Fei Pittcon 2009

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Cwa Invited Talk Fei Pittcon 2009

  1. 1. Securing Our Nations Water Supplies: Detecting Poisons by SERS Frank Inscore, Chetan Shende, Atanu Sengupta, and Stuart Farquharson Support: EPA: EP-D-05-034, EP-D-06-084www.rta.biz Providing Chemical Information When & Where You Need It
  2. 2. Challenge: specific, fast, sensitive• Specificity – identify chemical agents & hydrolysis products • No False Positives!• Speed – monitor poisoned water (batch & continuous) • 10 min or less• Sensitivity – Requirements to protect • CN – 6 mg/L (6 ppm) • HD - 100 microg/L (100 ppb)  TDG • Nerve - 5 microg/L (5 ppb)  MPA Part-per-billion is challenging! Providing Chemical Information When & Where You Need It
  3. 3. Analysis: CWA Hydrolysis Products H2 OHCN H3 O+ + CN- H2 O TDG 2 HCl + HD S S Cl Cl HO OH O O H2 O DIASH + P O H2 O N EMPA ethanol + O OH HS P VX P N O OH MPA O S HO H2 O EtOH + EA2192 DIASH + MPA P N O S O N H2 O O N H2 O O N GA P HCN + EDMAPA ethanol + O P P DMAPA C N O OH O OH H2 O O H2 O O HF + IMPA 2-propanol + MPA GB P P O F O OH H2 O H2 O GD O HF + O PMPA 2-pinacolyl + MPA P P O F O OH H2 O H2 O O O CMPA cyclohexanol + MPA GF HF + P P O F O OH Providing Chemical Information When & Where You Need It
  4. 4. Approach: Surface-enhanced Raman Spectroscopy When a molecule is within a plasmon field, hν the efficiency of Raman scattering Ag can increase by 1 million times! H N H O N Sub part-per million detection H P O NS H N N N H becomes possible. VX Chemical contribution Plasmon Fieldcan provide additional 103 enhancement Surface-Enhanced Raman Photon Single Molecule Detection: requires 1012 -1014 Providing Chemical Information When & Where You Need It
  5. 5. SERS-Active Substrates benzenethiol 10-3M 10-5M 10-8M (~10 ppb) Providing Chemical Information When & Where You Need It
  6. 6. Approach: RTA SERS Sampling Systems 2001: Simple SERS Sample Vials Molecules Sol-Gel Matrix Raman in Solution Scattering 2001 Laser Adsorbed Molecules Metal Particle 2004: SERS-Active Capillary 1 10 More suited to extract and pre-concentrate Providing Chemical Information When & Where You Need It
  7. 7. 2007: Functionalized Sol-Gel SERS Capillary PC OTC unreduced reduced Std SERS vials 2nd generation Providing Chemical Information When & Where You Need It
  8. 8. RTA’s Portable Raman Analyzer 1064 nm Advantages: • No sample preparation • Simple integration via fiber optics • Remote analysis, multi-component 25 pounds • Complete spectral coverage water tight • Wavelength stability • Confident spectral subtraction • and library search/match 785 nm • Real-time, On-demand analysis • Long term stability • Temperature and vibration immune • Shock resistantSERS-Active Capillary Providing Chemical Information When & Where You Need It
  9. 9. Potassium Cyanide: IR, NR, SERS Infrared (solid) CO2 Raman (saturated 2080 cm-1 solution, 1W, 10 min) SERS (1 mg/ml water 2140 cm-1 100 mW, 1-min) Wavenumbers (∆cm-1)Enhancement Factor ~ 3x106 Providing Chemical Information When & Where You Need It
  10. 10. SERS: cyanide 2003 (Vial) 2005 (Capillary) 2007 (F-Cap) PPM PPB PPT 100 100 10000 10 10 100 1 1 1100 mW 785 nm, 1-minSERS is Non-linear (Langmuir function) Providing Chemical Information When & Where You Need It
  11. 11. Thiodiglycol (TDG): SERS & NR SERS: 1 mg/mL, 1.5-min 100 mW 785 nm Raman: neat solution, 5-min 300 mW 785 nmEnhancement Factor = 2x105 Providing Chemical Information When & Where You Need It
  12. 12. SERS: Thiodiglycol 2005 (Capillary) 2007 (F-Cap) PPM 1 10 PPB 10 100 1000100 mW 785 nm, 1-min Providing Chemical Information When & Where You Need It
  13. 13. SERS: MPA SERS: 0.1 mg/mL, 1-min, 100 mw 785 nm 756 C PC P Raman: 1000 mg/mL, 5-min, 300 mw 785 nmEnhancement Factor = 8x105 Providing Chemical Information When & Where You Need It
  14. 14. SERS: Methyl Phosphonic Acid 2003 (Vial) 2007 (F-Cap) P-C 760 PPM PPB 1000 1000 100 100 10 10100 mW 785 nm, 1-min Providing Chemical Information When & Where You Need It
  15. 15. SERS: Methyl Phosphonic Acid 0.075 SERS MPA 0.05 Peak height ppb 0.025 1000 0 500 0 100 200 300 400 500 600 700 800 900 1000 Concentration (ppb) 250 12525 ppb Providing Chemical Information When & Where You Need It
  16. 16. SERS: 10 parts-per-billion MPA TDG CN Providing Chemical Information When & Where You Need It
  17. 17. SERS: Alkyl Phosphonic Acids1 ppm Providing Chemical Information When & Where You Need It
  18. 18. SERS: 10 parts-per-billion IpMPA PMPA CMPA EMPA DIASH80 mW, 785 nm, 1-min Providing Chemical Information When & Where You Need It
  19. 19. SERS: 10 parts-per-billion CEMS CEES HEES40 mW, 785 nm, 30-sec Providing Chemical Information When & Where You Need It
  20. 20. SERS: 10 parts-per-billion Fonofos Chlorobenzoic Acid Sunset Yellow80 mW, 785 nm, 1-min Providing Chemical Information When & Where You Need It
  21. 21. Summary: specific, fast, sensitive• Specificity – identify chemical agents & hydrolysis products • No False Positives!• Speed – monitor poisoned water (batch) • 10 min or less – 1 minute• Sensitivity – Requirements Lowest Measured Concentration! • CN – 6 mg/L (6 ppm) CN – 1 ng/L (1 ppt!) • HD - 100 microg/L (100 ppb) TDG - 10 microg/L (10 ppb) • Nerve - 5 microg/L (5 ppb) MPA - 10 microg/L (10 ppb)“pH dependence MPA, DPA, CN by SERS”, SPIE, 5269, 117-125 (2004)“SERS Analyzer for Monitoring Chemical Agents and Their HydrolysisProducts”, IJHSE, 102-111 (2007) Providing Chemical Information When & Where You Need It
  22. 22. Continuous Monitoring 1) Preliminary lab Measurements Fiber Optic cable 10 ppb CN! to instrument 3) Interface design to sample extraction line SERS-active capillary 1/8” Tygon opening to tubing pass light 5” FO Probe2) 10 ppb food dye hole to pass & Mount for water mounting screw supply tests threaded for 1.5” device 1.5” attachment SERS-Capillary Interface Block 3” Providing Chemical Information When & Where You Need It
  23. 23. Future Work: NeSSI &Real-World SamplingParker-Hannifin Swagelok Providing Chemical Information When & Where You Need It
  24. 24. NeSSI &Real-World Sampling 3-Way 3-Way Surface Ex- Surface 3-Way Surface SERS Surface Valve Valve Connection tractor Connection Valve Connection Sensor ConnectionRegulated Water Sample MeOH Pump Waste Bottle Bottle Load Sample Into Extractor (5 min) Providing Chemical Information When & Where You Need It
  25. 25. NeSSI &Real-World Sampling 3-Way 3-Way Surface Ex- Surface 3-Way Surface SERS Surface Valve Valve Connection tractor Connection Valve Connection Sensor ConnectionRegulated Water Sample MeOH Pump Waste Bottle Bottle Load Sample Into SERS Capillary (10 sec) Providing Chemical Information When & Where You Need It
  26. 26. NeSSI &Real-World Sampling 3-Way 3-Way Surface Ex- Surface 3-Way Surface SERS Surface Valve Valve Connection tractor Connection Valve Connection Sensor ConnectionRegulated Water Sample MeOH Pump Waste Bottle Bottle Measure SERS Load Next Sample Into Extractor (5 min) Providing Chemical Information When & Where You Need It
  27. 27. In Progress Providing Chemical Information When & Where You Need It

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