Overview of Raman Spectroscopy and portable markets Mark Schnittker 2013, Aug-23 [email protected] 408-368-1064 Some common measurement techniques General Techniques Fluorescence Refractometry Reflectometry Absorbance Molecular techniques (usually organic) Chromatography Mass spectroscopy Vibrational Spectroscopy IR resonance Atomic techniques (usually inorganic) X-ray spectroscopy Optical absorption Plasma discharge Trans FTIR Refl FTIR FTIR ATR Thermal Spectroscopy . Scattering Resonance Raman spectroscopy FT Raman Surface Enhanced Raman (SERS) How vibrational spectroscopy works Every molecule has vibrational modes (states). Vibrational modes = 3N-5 or 3N-6 pending the type of molecule where N=number of atoms “Group theory” determines which vibrational modes are “IR active”, “Scattering active”, or “forbidden”. Vibrational modes are quantized and will absorb photons of a specific energy (IR spectroscopy), or steal that same amount of energy from an incident photon and change the wavelength of the scattered photon (Raman spectroscopy). FTIR and Raman spectrum of Glucose showing vibrational modes 1.20E+00 FTIR Glucose in H2O Raman Glucose in H2O 1.00E+00 Marker lines 8.00E-01 6.00E-01 4.00E-01 2.00E-01 0.00E+00 1400 1200 1000 . (1/cm) Wave number 800 600 400 What information is in the spectrum? Triple Bonds Double Bonds Single Bonds Molecular rotation information Harmonics Carbonyl group Lattice vibrational modes 200cm-1 Raman of similar chemicals Most of the identifying signatures are in the 5001500 cm-1 range Carbonyl group in the 1600-1900cm-1 range is good at differentiating similar chemicals. With a good filter, raman can show lattice vibrational modes down at 200cm-1 which describes the physical structure of the sample. acetone ethanol Dimethyl sulfoxide Ethyl acetate toluene Why is Raman spectroscopy “special”? Visible Mid IR NIR Laser Raman Scattering moves information to shorter wavelengths Molecular Bond information is in this range FTIR sees this region Raman Bond information similar to FTIR Anti-Stokes Water Absorption Stokes Low cost optics High resolution arrays No water absorption Fluorescence C.V. Raman Attributes of Raman Spectroscopy -Consequences Probability of Raman scatter ~1E-6. – – – – Avoids water absorption – – Quantitative measurements are difficult Raman is good at determining the presence of a molecule but not good at determining percentages. Centering based on available detectors and lasers – – Able to see many of the molecular resonances Works well with aqueous solutions Probability of Raman scattering has dependencies (angular, temperature, ext) – – Needs lots of laser power Can over heat samples which have low Raman activity and low thermal conductivity Does not work well for trace detection (SNR of CCD) Does not work well with low density samples (gasses) Has very low cost options Fluorescence is often an issue Sensitive to polarizable bonds like C=C C=N , but less sensitive to dipoles like O-H, C-H, N-H – Needs good detector sensitivity in the 500-1500cm-1 range . Raman design trade offs water absorption IR Si-CCD InGaAs array Fluorescence issues 532nm laser 650nm laser 785nm laser 830nm laser 100 Raman spectral range 80 Raman FTIR Raman 60 Raman 40 20 0 25250 20250 15250 10250 5250 250 Frequency (1/cm) Si detectors ~$50 with high pixel count High frequency lasers product too much fluorescence. Low frequency lasers “walk off” Si detector and reduce the available spectral range InGaAs detectors solve spectral range issues but are expensive and have reduced pixels=>lower spectral resolution . Raman market overview http://www.spectroscopyonline.com/spectroscopy/Articles/Market-ProfilePortable-Raman-Spectroscopy/ArticleStandard/Article/detail/773924 Portable Raman Markets overview Biological: Hydration, Glucose- needs good fluorescence removal. Must compete with transmission, fluorescent and low tech options. Homeland Security: Explosives and chemical agents detection. – needs built in chemical library Consumer products regulatory compliance: Detection of phthalates and other toxins in consumer products. –needs low cost and ease of use, and high SNR for trace detection. Law Enforcement: Narcotics Analysis –needs built in chemical library and authenticity certification Oil and Mining: Chemical /Mineral field analysis. Hazmat handling: First responders to accidents to evaluate threat – needs built in chemical library and sealed. Portable Raman Markets overview Cont. Environmental: Field evaluation of contaminants in waterways and soils. These can also be permanently mounted modules in a distributed sensing network. –needs super weather tight and UV resistant housing Pharmaceuticals: Confirm shipments and mixtures through containers. – needs large spectral rang, carbonyl group detection. Defense: Combat troops to check for explosives and chemical weapons facilities –needs compact, light weight, battery powered, hermetically sealed Authenticity: Counterfeit detection of paintings, money, branded alcohol. –needs low fluorescence to see through glass Waste Management: Identification of reclaimed materials to determine proper recycling method –needs high speed, high efficiency to measure plastic fast without carbonizing it. Process Raman Market. Process Raman uses small rugged modules which are connected via USB to send back spectrum insitu from the manufacturing line. Pharmaceuticals, plastics, petroleum, and chemical manufacturing companies are the final customers of process Raman. Example 1: Placing a small Raman module on the outside of a rotating drum to monitor the mixture of pharmaceutical chemicals Example 2: Leak detection. Sensor module mounted at each valve or potential leak point, per recent new regulation of hazardous emissions. Key specifications (and how to engineer them) Need to see and know the peaks Fluorescence avoidance (Excitation laser l, post process/fluorescence subtraction, feature-free spectral throughput, very good spectral throughput calibration) Spectral range (Excitation laser l, Detector choice) Signal to noise (optical scattering, Laser power, detector dark current, electrical noise, integration time, optical throughput) Accuracy (temperature stabilization, calibration methods) Resolution (Spectrometer design, detector choice) Size, Weight, Ruggedness, Battery life . Existing Portable Market Participants Company Product, Average Selling Price Market Thermo Scientific First Defender Homeland Security B&W Tek NanoRam Laser 785nm 300mW 2502875 cm-1 resolution 8-10.5 cm-1 1753200 cm-1 <10 cm1 FirstGaurd 532, 785, 1064nm 500mW Intevac Spectral range Pharmaceuticals and Toxins 785nm 300mW Rigaku Comments Pharma-ID 2002000 cm-1 7-10 cm1 Geology, Pharmaceuticals, Hazardous materials 785nm <100m W 3002400 cm-1 10-12 cm-1 Purchased from Ahura for $140M in 2010, and now has the largest market share. Awarded FDA contract over Thermo by being more willing to work with FDA. Purchased from Bay Spec for undisclosed amount. Bayspec no longer allowed in handheld space. Purchased from DeltaNu in 2007 Existing Portable Market Participants Cont. Company Ocean Optics Product, Average Selling Price Market Pin Pointer General Laser 785nm 5500mW Comments Spectral Range 2002400cm1 Resoluti on Purchased from Raman Systems 10 cm-1 Jasco RPM300 Authenticity. Art paintings Enwave Optronics EZ-Raman Defense Hazmat 785nm 300mW OptoTrace Ram Tracer 1002700 cm-1 Small volume specialty market 6.5 cm-1 Japanese backed Chinese company with silicon valley operations. Redox module is very compact. Designed for biological applications Specs: 830nm @140mW. 300-1700 cm-1 spectral range. ~10cm-1 resolution Power/Data Cable Optical Port Data processing and bluetooth transmitter Raman Module 65mm square Optional LiIon Battery Light weight molded optics with laser and integrated spectrometer Redox attributes in this market based on current product form. Small size and weight Connectivity over cellular to libraries Bluetooth enabled Dynamically adjustable laser power High Signal to Noise Ratio Module is “smart” with on-board processing. Scratch resistant optical contact Internal temperature stabilization Reliable-Ruggedized Auto proximity sensor for laser eye safety concerns Can be USB controlled Battery operated option Sealed Investigating technical needs of a market segment Partner with a customer which can test efficacy of a system. Many chemicals have been cataloged in Raman databases. To investigate a market, find out what chemicals are involved in that market and pull up their spectrum. Evaluate what spectral range and resolution would be needed to identify the chemical. acetaminophen Minerals . Want to get measurement in-house? Portable Raman Too integrated. Not flexible enough Research grade Fiber coupled Good match. Flexible, and less expensive Too expensive and requires skilled operator Home brew: Most flexible. Good if you have in house expertise. Make a cheap fluorescence set up and explore excitation wavelengths before investing in a Raman system. . Thanks Mark Schnittker Market development specialist contractor for Redox [email protected] 408-368-1064 .