NEW MEASUREMENT PROCEDURE OF THE ACETALDEHYDE CONCENTRATION IN WORK PLACE AIR

The purpose of the work is to develop measurement procedure of the acetaldehyde concentration in work place air on the basis of headspace chromatographic analysis. According to the measurement procedure, acetaldehyde from the work place air is concentrated into distilled water in a volume of 5 cm3 placed in three cooled successively connected absorption devices. Acetaldehyde extraction from the absorption solution is carried out by gas extraction by heating the sample in a closed volume in the presence of sodium sulfate at a concentration of 0,2 g/cm3 using an automatic equilibrium vapor dispenser (vapor volume - 2 cm3). The headspace chromatographic analysis is carried out by gas chromatography simultaneously with polar ZB-Wax and weakly polar DB-624 capillary columns. The acetaldehyde mass concentration in the work place air is established by the method of absolute calibration. In the process of the metrological certification of the measurement procedure, indicators of precision and accuracy were established in the range of measurements of acetaldehyde mass concentrations in the work place air from 1.0 to 10.0 mg/m3. The limit of repeatability of the developed measurement procedure is 17.6%, the limit of intermediate precision is 22.4%, the relative expanded uncertainty is 15% with a confidence probability of p = 0.95 and coverage factor k = 2, the accuracy indicator is not significantly different from unity. The measurement procedure MVI.MN 6023-2018 «Acetaldehyde mass concentration in the work place air. The measurement procedure by gas chromatography» was certified by the Belarusian State Institute of Metrology (metrology certificate No. 1115/2018 dated July 25, 2018).

work place air, acetaldehyde, headspace chromatographic analysis