To this date, there are two main types of gas analyzers capable of measuring the concentration of substances in various media. Chromatographers belong to the first type, they are based on the method of substances distribution between the two phases – immobile (solid phase) and mobile (gas or liquid phase); these devices are used for analyzing the composition of gas media including identifying alcohols, hydrogen sulfide and inorganic compounds (nitrogen, oxygen, hydrogen, carbon monoxide and carbon dioxide).
The second type is represented by detectors analyzing the composition of substances by way of studying the parameters of electrons released from atoms or molecules exposed to plasma. This approach is based on unique energy levels of each element including ionization energy: it allows for defining the chemical make-up of a sample by way of analyzing the energy spectrum of the released electrons.
The researchers combined the detector and the chromatographer in a single analytical device. “During our experiments we demonstrated the possibilities for a broader application of plasma electronic spectroscopy to identify the composition of gas mixes using the example of He+CH4(600 ppm)+N2+O2 (700 ppm) — the mix of helium, methane, nitrogen and oxygen”, the Saint-Petersburg University is citing Sergey Sysoyev, the assistant professor of the Department of optics, spectroscopy and plasma physics.
In complex compositions, certain components may feature similar physical or chemical properties, which makes it difficult to distinguish between them. For example, signals from two different gases may overlap at the energy scale, and the traditional methods are not always capable to identify them. The new device is capable of better separation and identification due to adding a time coordinate to the analysis. At first, the device separates the mix into components, and then analyzes them by chemical and physical properties taking into account the time needed for them to go through the system.
Hence, the analysis is performed at both the time scale and the energy scale, which improves the accuracy of measurements.
