Proficiency testing for metals

Production of the sampling media

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Wind tunnel and measurement chamber at IGF
Source: IGF Technikum Dortmund.

Filter samples bearing metal particles will be shipped. Sampling is performed by means of the total dust sampling system (GSP) on cellulose-nitrate filters (pore size: 8 µm; diameter: 37 mm).

These samples are produced at the Institute for the Research of Hazardous Substances (IGF) of the German Social Accident Insurance Institution for the raw materials and chemical industry (BG RCI) in Dortmund. Aqueous metal salt solutions are pyrolysed by means of a flame generator. The resulting metal oxide particles are passed at a defined air flow rate through a steel tube (wind tunnel) with a length of 20 m and a diameter of 0.5 m (Figure). This tube opens into a measurement chamber with a volume of approximately 20 m³ in which the sampling units are located. Homogeneous distribution of the particles is assured at all points within the measurement chamber [1].

The concentrations are to be within a range of 0.1 to 2 times the applicable limit values (Table). In consideration of the analytic performance of the analysis methods to be employed, deviating concentration ranges are expected to be selected for copper, cobalt and nickel. These will be made known in good time.

Each participant receives a sample kit comprising:

  • Three loaded sample carriers, and
  • Four unloaded sample carriers for blank value adjustment.

The analysis method (AAS methods, ICP) may be selected freely. The recommended digestion method is that published by the DFG (the German Research Foundation) [2] and the IFA [3] for the digestion of metal dusts.

The development of an optional microwave digestion is almost completed. It can be expected that the method is going to be approved before the next PT Metals in summer 2018. It will be published in the IFA folder No. 6015 probably in spring 2018. With its publication this method can be used as equal.

With the dispatch of the samples you’ll be provided with this method as well.

Limit values for metals in Germany

Metal Limit value in mg/m3
Zn 0.1 [4]
Cu 0.01 [4]
Pb 0.1 [4]
Ni 0.006 [4]
Co 0.0005 [5]


[1] Monsé, C. et al.: Development and Evaluation of a Nanoparticle Generator for Human Inhalation Studies with Airborne Zinc Oxide. Aerosol Sci. Technol. 48 (2014) No. 4, pp. 418-426

[2] Aufarbeitungsverfahren für Stäube zur Bestimmung des "Gesamtmetallgehaltes". In: DFG, Analytische Methoden zur Prüfung gesundheitsschädlicher Arbeitsstoffe, Luftanalysen. Band 1: Spezielle Vorbemerkungen, Abschnitt 4 "Probenahme und Bestimmung von Aerosolen und deren Inhaltsstoffen". 14. Lfg. Verlag Chemie, Weinheim 2005, pp. 31-32

[3] Aufarbeitungsverfahren zur Analytik metallhaltiger Stäube; Methodik zur Bestimmung des "Gesamtmetallgehaltes" (Kennzahl 6015). In: IFA-Arbeitsmappe Messung von Gefahrstoffen. Vol. 34, IV/2005. Ed.: Institut für Arbeitsschutz der DGUV (IFA), Sankt Augustin. Erich Schmidt, Bielefeld 2011 - Loose-leaf edition

[4] GESTIS International Limit Values

[5] [25] Technische Regeln für Gefahrstoffe:Tätigkeiten mit krebserzeugenden Metallen und ihren Verbindungen (TRGS 561 (PDF, 706 KB)), Ausg.10/2017. GMBl. (2017) Nr. 43, S. 786-812


Division 2: Chemical and biological hazards

Brigitte Maybaum
Krista Gusbeth
Franziska Nürnberger