Figure-of-Merit Characterization of Hydrogen-Bond Acidic Sorbents for Waveguide-Enhanced Raman Spectroscopy.

The optical properties of several hydrogen-bond acidic sorbent materials are evaluated in situ to assess their suitability for waveguide-enhanced Raman spectroscopy (WERS) of vapor-phase organophosphonates. A number of characteristics critical to WERS are evaluated for each sorbent: infrared absorption, Raman spectral background, and the limit of detection for a test hydrogen-bond-basic analyte (dimethyl methylphosphonate, DMMP). We describe the chemical properties of the sorbents that differentiate their optical properties for sensing. Then, we introduce a sorbent figure-of-merit that quantifies these differences and provides a framework to assess the quality of newly developed sorbent materials.