X-Ray Fluorescence Spectroscopy for Laboratory Applications. Jörg Flock

filters can interfere with the measurement signal and influence the analytical result. Further, these filters are not suitable for quantification, since the penetration of the dust into the filter increases the effects of matrix interaction and cannot be sufficiently modeled. They can be used for qualitative analyses.

      A further possibility for the deposition of aerosol particles is the use of impactors. In this case, the air stream is directed onto impact plates on which the particles stick. It is also possible to separate different particle sizes by the stepwise change in the airflow. The particles collected on the impact plates can be analyzed directly or transferred to other sample carriers.

      The optimal collection techniques and filter materials depend very much on the respective analytical problem and must be selected by appropriate tests. Some examples for the collection and preparation of dusts at different loads and with various analytical objectives are discussed in Section 10.10.1.

      Small single particles can be positioned on a sample holder and fixed with a material that does not contain any of the analyte elements – selected hair sprays have produced good result – the small particle can also be embedded in suitable backing material. The final preparation strongly depends on the sample material, its size, and the analytical task. A few applications are described in Chapter 15.