METHOD OF MEASURING CONCENTRATION OF GAS IMPURITY IN AIR Russian patent published in 2006 - IPC G01N27/14 

FIELD: analytical chemistry; analysis of gas mixtures.

SUBSTANCE: according to method of measuring concentration of gas impurity in air, volt-ampere characteristic I (U) is chosen as electrical characteristic. Preliminary calibration is carried out by placing detector in clean air and in gas sample which has known amount of impurity of foreign gas. Voltage and/or temperature of heating of gas-sensitive film are changed till nonlinear part emerges at volt-ampere characteristic. Voltage Uc is determined at which voltage volt-ampere characteristic changes to non-linear law. Moreover calibration is carried out by measuring volt-ampere characteristics inside voltage area being lower than Uc. Concentration dependence of changes in conductivity of detector in gas sample is determined relatively conductivity in clean air at initial part of volt-ampere characteristic within voltage area being lower than Uc. Changes in conductivity of detector are measured in clean air relatively to conductivity of detector when impurity is present. Concentration of impurity in air is found from value of the relation. Permanent presence of medium of comparison (clean air) is not necessary and all the measurements can be made by means of single detector.

EFFECT: improved precision of measurement.

2 cl, 11 dwg