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Novel Chemical Detection Strategies for TCE and PCE



A C. Pipino


Novel applications of cavity ring-down spectroscopy (CRDS) to chemical detection are described. Using a linear optical resonator with an intra-cavity double-Brewster-window flow cell, CRDS is employed to probe the optical response to adsorption of the surface-plasmon resonance (SPR) of an ultra-thin (0.2 nm), nanostructured Au film. Detection limits for trichloroethylene (TCE), perchloroethylene (PCE), and NO2 are found to be 710-8 mol/L, 210-8 mol/L, and 410-9 mol/L, respectively. As the ultra-thin nanostructured film is well described by a distribution of nanospheres with a mean diameter of 4.5 nm, Mie theory is employed to account for some aspects of the optical response. In a second implementation of CRDS, evanescent wave CRDS (EW-CRDS) is used to detect TCE, cis-DCE, and trans-DCE by probing the first C-H stretching overtones in the near-IR with a monolithic folded resonator (MFR), providing spectroscopic selectivity and a reversible response. In a comparison of EW-CRDS to previous sensing technologies, the sensitivity obtained using an unclad MFR for TCE detection is found to be comparable to that obtained with a long-effective-path-length optical waveguide using a TCE-enriching polysiloxane coating. By applying an analyte-enriching, protective coating to an MFR, EW-CRDS may provide a sensitive, selective, and robust technology for long-term environmental monitoring.
Abstracts Of Papers Of The American Chemical Society


absorption, cavity ring-down, evanescent wave, resonator, surface plasmon resonance, surfaces


Pipino, A. (2003), Novel Chemical Detection Strategies for TCE and PCE, Abstracts Of Papers Of The American Chemical Society (Accessed May 23, 2024)


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Created September 1, 2003, Updated February 17, 2017