All hydrocarbons have absorption bands both in the mid- and near-infrared regions of the spectrum. In the mid-infrared region, for example, alkanes absorb energy in the vicinity of 3.3 μm, while alkenes also exhibit spectral features in the 8 to 10 μm region due to the C=C double bond. In the near-infrared region, the related overtone and combination absorptions show up in the 1.5 to 1.8 μm region for most hydrocarbons.
By using infrared spectroscopy, it is possible to measure the quantities of different hydrocarbons in a gas mixture fast and without sample preparation, with a simple system. Depending on the typical composition and parameters of the gas mixtures, the sensitivity and component concentration range can be optimized for your needs through by changing the optical path of the measurement.
Different organic compounds that have absorption bands in the NIR and MIR regions of the spectrum include:
- alkanes, alkenes, and alkynes
- aromatic hydrocarbons
- alcohols and ethers
- carboxylic acids, esters, aldehydes, and ketones