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Highly Sensitive SER-Active Sol-Gel Substrates for Trace Chemical Detection
- 1. Highly Sensitive SER-Active Sol-Gel Substrates RTA SERS Team: Stuart Farquharson (CEO), Frank Inscore (R&D Director), Atanu Sengupta & Chetan Shende (Senior Research Chemists) • Substrates • Applications • Chemical Agents in Water • Pesticides/Adulterants in Food • Illicit Drugs in Saliva • Proteomics • Devices Booth 2825 www.rta.biz Providing Chemical Information When & Where You Need It
- 2. The SERS Promise (if) • Enable Raman Spectroscopy to provide routine sub part per million chemical analysis The SERS Delivery (then) • Extend Raman’s usefulness to a vast number of trace chemical analyses But… • Can a SERS-active medium meet the requirements of an analytical instrument? Providing Chemical Information When & Where You Need It
- 3. Performance Criteria 1. Sensitivity (LOD, LOQ, LMC) 2. Linearity 3. Selectivity 4. Reproducibility 5. Shelf-Life 6. Usable Media 7. Sample Requirements: gas, liq, sol 8. Production Costs
- 4. Surface-enhanced Raman Spectroscopy When a molecule is within a plasmon field, the efficiency of Raman scattering can increase by 1 million times! Sub part-per million detection becomes possible. Single Molecule Detection: Chemical contribution requires 1012 -1014 can provide additional 103 enhancement
- 5. SERS-Active Media Traditional: • Electrochemically Roughened Electrodes • Metal Colloidal Hydrosols • Metal Islands or Nanoparticles on Solid Supports • Metal Coated Surface Structures • Self-Assembled Monolayers (SAMs) Recent: • Metal-Doped Porous Media • Periodic Apertures in Metals • Metal Shells • Fiber Optic Tips Providing Chemical Information When & Where You Need It
- 6. Electrochemically Roughened Electrodes Features: 50-250 nm wide, Pentaamine(pyridine)Osmium 75-200 nm high Farquharson, et al (Weaver), JACS, 105, 3350 (1983) Providing Chemical Information When & Where You Need It
- 7. Electrochemically Roughened Electrodes Limitation: Identical ORCs 735 cm-1 do not produce -1.7Vsce 10 sec Identical Surfaces. Adenine in an Electrolytic Flow Cell Farquharson et al, SPIE, 3533, 1998 Providing Chemical Information When & Where You Need It
- 8. Silver and gold colloids in solution 10-25 nm Silver Colloid 30-50 nm Silver Colloid Lee & Meisel, J Phys Chem, Aggregates (spermine) 86, 3391 (1986) Graham, Smith et al, Anal Chem, 69, 4703 (1997) Providing Chemical Information When & Where You Need It
- 9. Vapor Deposition on Glass & Sol-Gels 1 micron 20 nm Silver film 5 microns Bis Pyridyl Ethene Gold Film on Sol-Gel Ruthenium Tris bypyridine Providing Chemical Information When & Where You Need It
- 10. Vapor Deposition on Spheres 10 microns Silver on polystyrene, silica, titania… Vo-Dinh, Anal Chem, 56, 1677 (1984); ibid, 87, 59 (1987) CWA Dosimeter Providing Chemical Information When & Where You Need It
- 11. Vapor Deposition…on nanospheres 200 nm Ag on 390 nm spheres Glucose on 1-decanethiol coating Haynes et al (Van Duyne), J Raman Spec, 36, 471 (2005) Providing Chemical Information When & Where You Need It
- 12. Vapor Deposition Shapes Benzenethiol on Truncated Pyramids Haes & Van Duyne JACS, 124, 10596 (2002) Providing Chemical Information When & Where You Need It
- 13. Metal coated spheres - Nanoshells Silver on silica spheres p-mercaptoaniline Jackson & Halas PNAS, 101, 17930 (2004) Providing Chemical Information When & Where You Need It
- 14. Periodic Apertures 300 nm Gold film 200 nm Silver film On inverted 1 Gold film 150 nm hole micron pyramidal ~250 nm hole 900 nm spacing pits Ghaemi et al. Phys Rev ~450 nm spacing Rowlen (web site) Perney et al, Optics B, 58, 6779 (1998) Express, 14, 847 (2006) Providing Chemical Information When & Where You Need It
- 15. Traditional SERS-Active Media Major Limitations: • Electrodes - Irreproducible Roughness • Colloids - Unstable Media (e.g. pH) • Vapor Coated Spheres – no substrate-to-substrate consistency • Specific Structures - less enhancement • Stringent Sample Requirements (e.g. solvent) • Expensive Devices • Irreversible (single measurements) Providing Chemical Information When & Where You Need It
- 16. Which do you want: Sensitivity or Reproducibility? 1 square micron = 12.6 silver particles Laser spot (325 micron diameter) = 83,000 square microns i.e. contains 1.04 million silver particles Or the equivalent of 1 perfect hot spot generating 1012 enhancement 10 microns SERS: silver particles in sol-gel Providing Chemical Information When & Where You Need It
- 17. SERS-Active Substrates benzenethiol 10-3M 10-5M 10-8M (~10 ppb) Providing Chemical Information When & Where You Need It
- 18. 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
- 19. 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
- 20. Analysis: CWA Hydrolysis Products H2 O HCN 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
- 21. SERS: 10 parts-per-billion MPA TDG CN Providing Chemical Information When & Where You Need It
- 22. Parker-Haniffin Intraflow Sample System Providing Chemical Information When & Where You Need It
- 23. Measurements using NeSSI 10 ppb CN- 100 ppb TDG 50 ppb 75 ppb MPA Sunset Yellow Spiked Water “EWS-2008-002” from Kensico, NY water reservoir Providing Chemical Information When & Where You Need It
- 24. User Interface Providing Chemical Information When & Where You Need It
- 25. Challenge: minimize pesticide contamination • Need pesticides to meet food demand (US imports 33 million tons of fruit) • 2.8% of imports exceed guidelines • Only 1 % is tested Shende et al SPIE, 5587, ??? (2005) Providing Chemical Information When & Where You Need It
- 26. Challenge: Detect Residues in Food & Feed Residues in Food Baby Food Feed DDT carbaryl malathion chlorpyrifos-methyl chlorpyrifos-methyl chlorpyrifos-methyl malathion malathion chlorpyrifos endosulfan permethrin methoxychlor dieldrin ethylenethiourea tribufos chlorpyrifos endosulfan pirimiphos-methyl chlorpropham chlorpyrifos diazon permethrin iprodione ethoxyquin iprodione thiabendazole ethion chlordane dimethoate gardona Requirements 10 ppb to 10 ppm. Providing Chemical Information When & Where You Need It
- 27. Analysis: methyl parathion Normal Raman Normal Raman Surface-Enhanced Raman Surface-Enhanced Raman Providing Chemical Information When & Where You Need It
- 28. Analysis: Chlorpyrifos Normal Raman Normal Raman Surface-Enhanced Raman Surface-Enhanced Raman Providing Chemical Information When & Where You Need It
- 29. Swab Test: carbaryl on an apple 1 Spray 2 Swab 3 Extract 4 Measure Providing Chemical Information When & Where You Need It
- 30. Sensitivity: 10 ppb 75 mW of 785 nm 1 min Providing Chemical Information When & Where You Need It
- 31. SERS of Melamine 0.5 PPM (X20) Glass Luminescence 5 PPM Simple SERS Pure Melamine Sample Vial Providing Chemical Information When & Where You Need It
- 32. SERS of Melamine 0.5 PPM in Solvent (X20) Glass Luminescence 5 PPM in Solvent 250 PPM extracted Simple SERS from Baby Formula Sample Vial Providing Chemical Information When & Where You Need It
- 33. Challenge: determine overdose drug • 1/3rd of all ER cases are drug overdose related • 50% are due to cocaine • Cocaine overdose symptoms are similar to many other ER cases, particularly heart attack • A 5-min diagnosis would be invaluable to select treatment • Current analysis of drugs use 10-20 ml blood • Centrifugation to remove red blood cells • Extraction using organic solvents • Separation using chromatography • Detection with UV or Mass Spec • Standards are needed to ensure measurement accuracy • These methods are labor intensive, time consuming, • Analysis time is typically 30-60 min. Providing Chemical Information When & Where You Need It
- 34. Solution: Saliva analysis by surface-enhanced Raman • Drug metabolites represented in saliva • Usually 10-50% of blood plasma (1-10 microg/mL) • Non-invasive (no needles) • Saliva is 99.5% water • Interfering physiological chemicals 100X less than blood • But Currently analyses require 10-20 cc • Raman – chemical specificity • SERS – increased sensitivity (goal=1 mg/L, 1ppm) • Simple SERS Syringe • Small sample volumes – 100 microL (few drops) • Rapid analysis time (1-2 min) Shende et al SPIE, 6007, ??? (2005) Providing Chemical Information When & Where You Need It
- 35. Analysis: cocaine Normal Raman SERS Wavenumbers 300 microliter sample (6 drops) All 0.33 mg/mL Providing Chemical Information When & Where You Need It
- 36. Drug Detection on a Universal SERS Chip 2 inches Benzoylecgonine Methanol Cocaine 300 microliter sample (6 drops) All ~50 ppm Providing Chemical Information When & Where You Need It
- 37. Simple SERS Sample Vials: Uniform Coatings Significant improvement in RSD using new high-speed roller Providing Chemical Information When & Where You Need It
- 38. Chemical Residue Detector A Portable, Field usable SERS Analyzer 5 Pounds 10” 5” 3.4” Providing Chemical Information When & Where You Need It
- 39. Chemical Residue Detector 1-10 ppm TNT Melamine Chlorpyrifos-Methyl Methyl Phosphonic Acid Aspirin Aspargine Raman Shift, cm-1
- 41. Proteomics (Amino Acid Sequencing) Providing Chemical Information When & Where You Need It
- 42. 96-Well SERS-Active Plate We develop SERS Sample Systems for You Booth 2825
- 43. Challenge: regulate drug dosage • Chemotherapy drugs also kill non-cancer cells • Dosage is critical • No clinical trials to establish statistical based dosage • Current analysis of drugs and metabolites use 10-20 ml blood • Centrifugation to remove red blood cells • Extraction using organic solvents • Separation using chromatography • Detection with UV or Mass Spec • Standards are needed to ensure measurement accuracy • These methods are labor intensive, time consuming, unsafe • Consequently, measurements made on an “as needed” basis Providing Chemical Information When & Where You Need It
- 44. Background: 5-Fluorouracil (5-FU) O H 4 F • One of most widely used chemotherapy drugs 5 N3 2 6 • Colorectal carcinoma O 1 N H • Structure similar to uracil H • Metabolites incorporate into RNA and DNA • Wide genetic-based variation in metabolism, 15-80% inactive • Half life is 5-20 minutes •Various dosage regimens based on type and phase of cancer • Concentrations in saliva similar to blood plasma Farquharson et al J Raman Spec, 36, 208 (2005), Vib Spec, 38, 29 (2005) Providing Chemical Information When & Where You Need It
- 45. Analysis: 5-Fluorouracil Normal Raman Surface-Enhanced Raman Providing Chemical Information When & Where You Need It
- 46. Simple Separation Devices 5FU A & 5FUH2 SERS-Active Lab-on-a-Chip Sample Injection 5FdUrd Syringe B C A Leucovorin B C Simulated analysis of 600 800 1000 1200 1400 1600 Wavenumbers (cm-1) 5-FU in saliva Providing Chemical Information When & Where You Need It
- 47. Challenge: sensitivity, speed, specificity • Sensitivity – protect exposed personnel • Anthrax LD50 estimated at ~10,000 spores (100 nanograms) • Goal is closer to 100 spores/cm2 • Speed – need to map area (target 1 min per spot) • Specificity – extreme minimum in false positives • Current methods: • DNA or RNA enumeration: (Culture growth - 24 hours) or Polymerase Chain Reactions (PCR, >4 hours) • test kits (limited shelf life, very high false positive rate) Providing Chemical Information When & Where You Need It
- 48. Approach: measure anthrax signature - CaDPA Core Wall Cortex (proteins-cysteine, (peptidoglycan) Ca dipicolinate) DNA 2- Ribosomes O O Ca 2+ O C N C O Spore Coat Exosporium CaDPA Farquharson, Maksymiuk & Inscore Appl Spec, 58, 351 (2004) Providing Chemical Information When & Where You Need It
- 49. SERS and RS of dipicolinic acid (DPA) 10 mg/L SERS Sat’d KOH sol DPA by Raman SERS: 150 mW, 1-min, NR:450 mW, 5-min Providing Chemical Information When & Where You Need It
- 50. Extraction & Identification of DPA in 2-min! 0. Dried 2200 spores from 1 microliter 1. Added 10 micoliters of SporeDestroyer (1-min digestion) 2. Suck 1 microliter into 3. Measure SERS of DPA SER-active capillary (10-sec) (10% = 220 pg/microliter) (10-sec placement, 30-sec scan) Providing Chemical Information When & Where You Need It
- 51. SERS: 220 Spores 220 pg/microL DPA 100 pg/microL (ppb) reference spectrum Internal Reference 1000 pg/microL = 1 ppm, no big deal Providing Chemical Information When & Where You Need It