FTIR (Fourier Transform InfraRed) spectroscopy is the most popular analytical technology for applications requiring continuous measurement of multiple parameters simultaneously. Typically, FTIR analyzers are employed for process control and emissions monitoring. However, due to the robustness and flexibility of this technique, it can also be applied in a wide variety of different applications.
FTIR gas analyzers identify and measure gaseous compounds by their absorbance of infrared radiation. This is possible because the combination of atoms and their arrangement is unique to every molecular structure, and therefore molecules produce a unique spectrum when exposed to infrared light. Instrumental analysis of the spectrum gathered from infrared with wavelength around 2-12 micrometers enables the qualitative identification and quantitative analysis of the gaseous compounds in the sample gas.
FTIR analyzers are able to simultaneously measure multiple analytes in complex gas matrices, detecting virtually all gas-phase species, both organic and inorganic. Some exceptions are diatomic elements like N2, O2 and noble gases like He, Ne. For example, the Gasmet FTIR gas analyzer collects a complete infrared spectrum 10 times per second. This infrared spectrum is a measurement of the infrared light absorbed by molecules inside the sample gas cell. Multiple spectra are co-added together according to selected measurement time. This improves accuracy by raising the signal-to-noise ratio. The actual concentrations of gases are calculated from the resulting sample spectrum using a modified Classical Least Squares analysis algorithm.