Infrared spectroscopy is great for determining the composition of liquids. Combined with attenuated total reflection (ATR), one can just put the sample on the sensitive surface. We made a compact device with a diamond-coated silicon ATR crystal to protect the surface against aggressive fluids. Silicon crystal, light source and detector are hermetically sealed in a housing. Our tests show that the diamond coating enhanced the sensitivity compared to uncoated ATR elements as predicted by theory.

Imaging of greenhouse gases is of great interest due to global warming. A spectroscopic method, using an active illumination of the scene, is presented. It allows for imaging and concentration measurements of much smaller gas plumes and leaks than current state-of-the-art gas cameras (optical gas imaging cameras). A real-time camera is realized and validated using known methane concentrations.

We present a photoacoustic sensor enabling fast, inexpensive, and highly sensitive methane detection in environmental monitoring applications. Six different T-cell designs were both theoretically and experimentally investigated. The aim was to understand the photoacoustic signal generation and resonances in relation to the different cell geometries, and determine the long-term stability and the detection limits for methane. These were below the methane background concentration in air of 1.8 ppm.

Detection of flammable gases is necessary to avoid explosive atmospheres. Commercial pellistors require an operation temperature above 450 °C for the detection of methane. We present a novel wireless low-power catalytic gas sensor system based on non-precious metal catalyst for the detection of methane and propane operated at 350 °C. The combination of a MEMS-based sensor with a low-power radio system provides the opportunity to monitor complex infrastructures without using a power grid.

Differential thermal analysis (DTA) was used to examine the effect of the particle size and morphology of Co₃O₄ on its thermal response under exposure to 1 % CH₄. The DTA response results from the catalytic oxidation of methane. Co₃O₄ samples differing in particle size and morphology were produced by ball milling or were synthesized. The investigations performed with temperatures between 250 and 450 °C reveal that both particle size and shape have a considerable effect on thermal response.