Gas analysis is qualitative and quantitative composition of the various gas mixtures. In physiology or medicine is used to determine the gas composition of inhaled, exhaled and alveolar air and gases arterial and venous blood (see Gas exchange).
According to the gas analysis it is possible to calculate the amount of oxygen used for a certain period of time for oxidative processes, and the number of allocated during this same time, carbon dioxide. In humans gas analysis is made when calculating energy costs by indirect calorimetry (see).
Most methods of gas analysis is based on the absorption of the individual components of the gas mixture specific sinks. When the gas analysis of air as carbon dioxide absorber is usually used lye, and oxygen - alkaline solution pyragollole.
The study of the gas composition of blood was first implemented, I. M. Sechenov, who developed for this purpose a special device - "mercury pump". In the future, have been used chemical methods of analysis of blood gas composition.
To capture the dynamic changes of the gas medium composition give the opportunity to Express methods. In some of these methods uses the ability gases different absorb infrared rays or ultrasound vibrations. Other methods are registered changes in the electrical conductivity of metals when changing the chemical composition of air. Applies also polarographic method (see Polarography).
Gas analyzers - automatic or semi-automatic devices are used for definition of harmful impurities in the air of industrial, residential and other premises, as well as in the atmospheric air. The most widely used optical gas analyzers, the principle of which is based on the change of the light absorption of gaseous, liquid and solid media containing the matter under investigation. In practice hygienic researches are used chemical analyzers, based on the absorption of gases specially selected substances - indicators (changing its color). Wide application is found with gas analyzers, created the Leningrad occupational safety Institute (HS-1 and HS-2). These devices allow to determine in the air a number of substances: ammonia, gasoline, benzene, chlorine, acetone and other
Are also used gas analysers for determination of vapor mercury (jedco chief-450 and others). The effect of this device is based on the absorption of mercury vapor UV rays of a certain wavelength and registration of arising of the photocurrent. For detection in air arsenic hydrogen created PV analyzer FAAV-Sh. To determine carbon dioxide are chemical analyzers, based on the absorption C02 solutions of sodium hydroxide or sodium hydroxide. To determine carbon monoxide Kharkiv Institute of health established a special detector.
