Stickstoffdioxid – Bestimmung von Stickstoffdioxid in der Luft am Arbeitsplatz mittels Ionenchromatographie (IC)
Luftanalysen-Methode
Christian Monsé1 (Methodenentwicklung)George Dragan2 (Methodenentwicklung)
Ulrich Prott2 (Methodenentwicklung)
Christoph Emmel3 (Methodenprüfung)
Ralph Hebisch2 (Leitung der Arbeitsgruppe „Luftanalysen“ der Ständigen Senatskommission zur Prüfung gesundheitsschädlicher Arbeitsstoffe, Deutsche Forschungsgemeinschaft)
Andrea Hartwig4 (Vorsitz der Ständigen Senatskommission zur Prüfung gesundheitsschädlicher Arbeitsstoffe, Deutsche Forschungsgemeinschaft)
MAK Commission5
1 Institut für Prävention und Arbeitsmedizin der DGUV (IPA), Bürkle de la camp-Platz 1, 44789 Bochum, Deutschland
2 Bundesanstalt für Arbeitsschutz und Arbeitsmedizin (BAuA), Friedrich-Henkel-Weg 1–25, 44139 Dortmund, Deutschland
3 Berufsgenossenschaft der Bauwirtschaft (BG BAU), Am Knie 6, 81241 München, Deutschland
4 Institut für Angewandte Biowissenschaften, Abteilung Lebensmittelchemie und Toxikologie, Karlsruher Institut für Technologie (KIT), Adenauerring 20a, Geb. 50.41, 76131 Karlsruhe, Deutschland
5 Ständige Senatskommission zur Prüfung gesundheitsschädlicher Arbeitsstoffe, Deutsche Forschungsgemeinschaft, Kennedyallee 40, 53175 Bonn, Deutschland
Abstract
The working group “Air Analyses” of the German Senate Commission for the Investigation of Health Hazards of Chemical Compounds in the Work Area (MAK Commission) developed and verified the presented analytical method. It is used to determine the levels of nitrogen dioxide [10102-44-2] that occur in the workplace air. The method covers concentrations in the range from one tenth up to twice the current occupational exposure limit value (OELV) of 0.95 mg/m3 (0.5 ml/m3). Samples are collected by drawing a defined volume of air through a sampling tube filled with aluminium oxide carrier material coated with triethanolamine (TEA) using a flow regulated pump at a volumetric flow rate of 1.8 l/min. The exposure during the shift is assessed with a sampling period of 2 hours and the short-term exposure with a period of 15 minutes. Nitrogen dioxide reacts with TEA with formation of TEA nitrite and TEA nitrate. Nitrite and nitrate are extracted with ultra-pure water and analysed by ion chromatography using conductivity detection. The quantitative determination is based on multiple-point calibrations with external standards. A relative limit of quantification (LOQ) of 0.009 mg/m3 is obtained for an air sample volume of 216 litres. As the LOQ for a sample volume of 27 litres is well below 0.95 mg/m3, the short-term exposure limit (STEL; excursion factor 2) can also be measured. The mean recovery is 108% and the expanded uncertainty is below 28% for a sampling period of 2 hours.
