Novel Chemical Detection Strategies for TCE and PCE

Published

September 1, 2003

Author(s)

A C. Pipino

Abstract

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.

Citation

Abstracts Of Papers Of The American Chemical Society

Volume

226

Pub Type

Journals

Keywords

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

Citation

Pipino, A. (2003), Novel Chemical Detection Strategies for TCE and PCE, Abstracts Of Papers Of The American Chemical Society (Accessed July 27, 2024)