(in German)

The analytical method described here permits the simultaneous determination of manganese dusts and manganese compounds occurring in particulate form in the workplace air in a concentration range of one tenth up to twice the currently valid German Occupational Exposure Limits of 0.2 mg/m³ (inhalable dust fraction) and 0.02 mg/m³ (respirable dust fraction). The peak limits, each with an excursion factor of 8, can also be checked.

Sampling is carried out using a flow-regulated pump to draw a defined volume of air through a quartz fibre filter. The sampling head predetermines whether the inhalable fraction or respirable fraction is collected. Intake cones for 10 l/min as well as for 3.5 l/min can be used. The manganese deposited on the filter in the form of dust and particles is determined by a graphite furnace atomic absorption spectrometer (GF-AAS) after acid digestion using a high-pressure microwave digestion system. Quantitative evaluation is based on an external multiple-point calibration. If matrix influences occur, then the standard addition method is used for quantitative evaluation. The limit of quantification is 13.6 pg absolute and 0.02 μg/m³ for a sampling volume of 1.2 l and a sampling period of 2 h. The mean recovery is 96% and the expanded uncertainty for the validation range of 0.002 to 3.2 mg/m³ is 30% for the inhalable fraction and 27% for the respirable fraction.

Please download the article "MAK Commission: Mangan - Bestimmung von Mangan und seinen anorganischen Verbindungen in der Luft am Arbeitsplatz mittels Atomabsorptionsspektroskopie (AAS)" (in German only).