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Wayne Weimer (PI) and Monika Wilson, Agiltron Inc.

Portable SERS Detector for Simultaneous Detection of Trace-level Polycyclic Aromatic Hydrocarbons on Superfund Sites. Wayne Weimer (PI) and Monika Wilson, Agiltron Inc. Professor Lili He, University of Massachusetts Amherst SBIR Phase I Program Officer : Heather F. Henry

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Wayne Weimer (PI) and Monika Wilson, Agiltron Inc.

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  1. Portable SERS Detector for Simultaneous Detection of Trace-level PolycyclicAromatic Hydrocarbons on Superfund Sites Wayne Weimer (PI) and Monika Wilson, Agiltron Inc. Professor Lili He, University of Massachusetts Amherst SBIR Phase I Program Officer: Heather F. Henry Grant Number: 1R43ES022884-01A1 Project Period of Performance: 05/01/2015 – 10/31/2015

  2. The Problem and The Solution • Problem: Groundwater and soils at Superfund sites are contaminated with polyaromatic hydrocarbon (PAH) compounds at trace levels, 16 are EPA priority PAHs • Current methods • Require samples sent to laboratory • Field tests lack required sensitivity • Solution: Agiltron uses Surface Enhanced Raman Spectroscopy (SERS) in a unique way to detect these PAHs in water at 0.1 ppb levels • Our innovation: use a hydrophobic partition layer to extract PAHs directly from water sample for rapid ultrasensitive detection • Results show the potential to achieve detection limits below the target level of 0.1 ppb.

  3. Raman and SERS Technology • Raman spectroscopy identifies unknown molecules by their unique chemical bonding structure – routine at bulk concentrations • Measured Analyte SERS spectrum is compared to library spectra • Spectral match identifies analyte; Intensity proportional to concentration • SERS extends the method to trace level detection (ppb) • Signal enhanced by up to 108 due to strong localplasmonic electric fields formed adjacent to nanostructured substrate media Probe laser Raman scattered light Analyte samples on SERS media

  4. Agiltron’s SERS Based Solution • Adaptation of PinPointer™ Raman spectrometer for PAH detection • Development of hydrophobic partition layer to extract PAH from water sample for immediate identification and quantitation

  5. Library Construction (1) SERS Spectra of 7 Priority PAHs pyrene acenaphthene acenaphthylene fluorene anthracene naphthalene phenanthrene

  6. Library Construction (2) SERS Spectra of 9 Priority PAHs fluoranthene indeno[1,2,3-cd]pyrene benzo[a]anthracene benzo[b]fluoranthene benzo[a]pyrene benzo[ghi]perylene benzo[k]fluoranthene chrysene dibenz(ah)anthracene

  7. PAH Calibration Curves Phenanthrene Pyrene Indeno(1,2,3-cd) pyrene 2nd Derivative 980 975 970 965 960 955 Raman Shift (cm-1) 980 960 940 Raman Shift (cm-1) 1190 1185 1180 1175 1170 1165 Raman Shift (cm-1) Peak Area Pyrene conc. (ppb) Indeno(1,2,3-cd)pyrene conc. (ppb) Phenanthrene conc. (ppb) y = 0.049x + 0.922 R2 = 0.907 y = 0.2452x + 3.0497 R2 = 0.9425 y = 0.048x + 0.5097 R2 = 0.8966 Peak Area Log value of conc. (ppb) Log value of conc. (ppb) Log value of conc. (ppb)

  8. Validation on Portable Benchtop Raman System pyrene indeno(1,2,3-cd) pyrene Laser: 785 nm, 25 mW Integration time: 10 s AgNF phenanthrene

  9. Summary • Synthesis of a alkane-thiol based hydrophobic partition layer on silver nanoparticle SERS substrates was optimized • Excellent signal to noise ratio SERS spectra were obtained for all 16 target PAHs to construct a searchable library of spectra • Calibration curves were constructed successfully for 3 PAHs with limits of detection of 0.1 ppb and potentially lower • Time resolved SERS signals show effective extraction of waterborne PAHs For More Information Contact: Wayne A. Weimer, Ph.D. T: 781-935-1200 wweimer@agiltron.com

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