Cantilever-enhanced photoacoustic detection and infrared spectroscopy of trace species produced by biomass burning

Abstract

The applicability of cantilever-enhanced photoacoustic spectroscopy (CEPAS), which exploits the unique properties of a micromechanical lever sensor (cantilever) in combination with tunable quantum cascade lasers (QCLs), is evaluated for the monitoring of several species produced by biomass burning. The detection limits of the selected molecules (HCOOH, CH3CN, CH3OH, CH3COCH3, CO2, and N2O) for a commercial CEPAS unit (GASERA) used together with QCLs were estimated under laboratory conditions. The normalized noise equivalent absorption (NNEA) coefficients for these molecules were determined experimentally, and the theoretical detection limits for the relevant biomass-burning products, accessed in the spectral ranges of available commercial QCLs in the mid-infrared region, were extrapolated using the determined NNEA values and the spectra simulated with the SpectraPlot software.