METHOD OF THE QUANTITATIVE DETERMINATION OF AMMONIA IN THE AIR OF THE INDUSTRIAL PREMISES Russian patent published in 2008 - IPC G01N27/12 

FIELD: chemical industry; other industries; methods of the quantitative determination of ammonia in the air of the industrial premises.

SUBSTANCE: the invention presents the method of the quantitative determination of ammonia in the air in the industrial premises, which provides for usage of the piezoelectric quartz resonators (PQR) of the volumetric acoustic waves with the natural frequency of oscillations of 10 MHz, modification of their electrodes using the sorbent solution, the solvent removal, introduction of the being analyzed gas in the cell of the detection, registration of the analytical signal, construction of the calibrating graph and determination of the quantity of ammonia in the industrial premises. In the capacity of the modifier of the electrodes of the piezoelectric quartz resonator they use the mixture of the equal volumes of two solutions: polystyrene in toluene with the concentration of 1 mg/cm³ and zirconium nitrate in the ethyl alcohol with concentration of 9 mg/cm³ and with the ratio of the masses of the polystyrene and Zr^{4 +} in the mixed solution of 1÷9. The prepared mixture is applied on the electrodes by the single dipping of the piezoelectric quartz resonator for 5 s in the freshly made solution of the sorbent with the subsequent evaporation of the free solvents at the temperature of 20-25°С within 2 hours and the subsequent additional modification of the produced film by exposure of the sensor in the saturated vapors of phenol within 1 hour and desorption of the free phenol by holding of the sensor in the stream of the pure laboratory air during 30 minutes at the temperature of 20-25°С till stabilization of the signal of the sensor. The optimal mass of the so formed modifier compounds 7.7±0.8 microgram. It is possible to determine the mass of ammonia within the range of the concentrations of 10-500 mg/m³ is possible. The invention ensures the quantitative determination of ammonia in the air of the industrial premises within the broad band of the concentrations of 10-500 mg/m³ with the minimum effect of the air humidity on the sorption of ammonia by the atmospheric air, multiplicity of the sensor usage of without renovation of the film coating, the simplicity and the speed of modification of the electrodes, the cheapness and mobility of definition of ammonia in the air, including the continuous operation mode (on the site).

EFFECT: the invention ensures the quantitative determination of ammonia in the air of the industrial premises within the broad band of the concentrations, the minimum effect of the air humidity on this process, multiplicity of the sensor usage, the simplicity and the speed of the electrodes modification, the cheapness and mobility of definition of ammonia in the air.

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