scope:

The methods described here are used to determine elements after sampling with bulk and wet-only collectors (e.g., based on DIN EN 15841 or VDI 4320 Part 1 and Part 3, using graphite furnace atomic absorption spectrometry (GF-AAS), inductively coupled plasma optical emission spectrometry (ICP-OES), and inductively coupled plasma mass spectrometry (ICP-MS).

Note: The hydride technique (HG-AAS) can also be used for the elements arsenic and antimony. This analytical method is not entered into in this standard.

The methods can be used for the following purposes, in particular:

• measuring methods for the determination of arsenic, cadmium, lead, and nickel in atmospheric deposition in accordance with DIN EN 15841

• background measurements for the investigation of the deposition of air pollutants transported over large distances (e.g., spatial distribution and tendencies over time)

• elements in dustfall pursuant to the TA Luft (Technical Instructions on Air Quality Control), the Swiss Clean Air Act (LRV) or in line with the measurement concept for the Austrian Immission Control Act - Air

• elements in dustfall in the surroundings of industrial plants (plant-related measurements)

• determination of elements in dustfall at sites with heavy traffic and in urban areas (e.g., spatial distribution and tendencies over time)

The samples are taken to the laboratory after sampling with funnel-and-bottle systems. The sample solutions are acidified in the sampling bottles to dissolve the metals bound to particles or adsorbed on the walls of the container. The solutions are then analysed using suitable analytical methods, dependent on the expected concentration of elements.

The dustfall is generally determined after sampling with collecting pots. The dry residue is digested with an oxidising acid mixture to determine the elemental contents in dustfall samples. The digestion solutions are then analysed using suitable analytical methods, based on the expected concentrations of elements.

Table 3 gives an overview of the typical lower limits of the working range when using the analytical method ICP-MS for the determination of the deposition of elements. The limits of the working range refer to the concentrations of the elements in the acidified sample solutions (funnel-and-bottle systems) and/or in the solutions for measurement after digestion with acid (Bergerhoff method).

DIN EN 15841 proposes that the digestion and analysis of dustfall samples is carried out pursuant to DIN EN 14902. Experiments on element recovery from dusts with certified elemental contents have shown that the digestion method pursuant to DIN EN 14902, without using hydrofluoric acid, can produce lower results when determining elements in dustfall, in particular for elements bound as silicates.

The efficiency of different digestion variants for the determination of a variety of elements was tested on certified reference materials in an interlaboratory comparison, in which members of the research group participated [2].

VDI 2267 Part 3 gives a detailed description of digestion variants and their individual suitability. Table 4 gives the recoveries for elements in the certified reference material NIST 1648a "Urban Particulate Matter" for each digestion variant that was tested.

This reference material is also used to assess the efficiency of the digestion in the standards for the determination of elements in airborne dust and in atmospheric deposition (standards DIN EN 14902 and DIN EN 15841).

Table 4 shows that all digestion variants are essentially suitable for the determination of arsenic, cadmium, lead, and nickel in dustfall pursuant to DIN EN 15841.

It is to be noted that lower results are to be expected when determining nickel in the reference material NIST 1648a using digestion variant 3, at around 15%, and at around 10 % when using digestion variants 4 and 5.

Table 4 makes clear that recoveries of > 90 % are only achieved for all elements with digestion variants 6 and 7 at high temperatures and under the addition of hydrofluoric acid.

Lower results are also obtained for antimony if nitric acid is used as the sole digestion acid (digestion variants 4 and 5) due to the production of the insoluble meta-antimonic acid.