(in German)

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. This analytical method is a validated measurement procedure for the determination of germanium [7440-56-4] and its non-volatile compounds in workplace air in a concentration range of one tenth up to twice of the currently valid Occupational Exposure Limit Value (OELV) in Germany of 0.85 mg/m³ as germanium in the inhalable particle fraction. For sampling, a defined volume of air is drawn through a membrane filter (nitrocellulose). The flow rate is 10 l/min and sampling duration is 2 hours. Germanium is digested with a mixture of hydrofluoric and nitric acid in a microwave-assisted pressure digestion. The samples are subsequently analysed using mass spectrometry with inductively coupled plasma (ICP-MS). The quantitative determination is based on a calibration function. The limit of quantification is 0.004 μg/m³ for an air sample volume of 1200 l and 20 ml digestion volume. The mean recovery is 97.2% for germanium and 97.9% for germanium dioxide. The expanded uncertainty for the validation range of 0.085 to 1.7 mg/m³ is 35.7 to 24.4%.

Please download the article "MAK Commission: Germanium - Determination of germanium and its non-volatile inorganic compounds in workplace air using inductively coupled plasma mass spectrometry (ICP-MS)" (in German only).