Rapid method for EDXRF analysis of clayey and sandy soil

The success of quantitative full soil EDXRF analysis is strongly related to the ability establish a homogeneous and representative sample. When practicing thin‐film deposition techniques the soil particle size will furthermore have an influence on the quantification capability, especially when analyzing the light elements. Finally, the deposition of material on a substrate is coupled with the sedimentation mechanism, which again is influenced by the material grain size and uniformity. In the present investigation, an effective and simple micro‐milling technique for soil and sediment materials was tested. By light scattering it is demonstrated that a grain size of about 600 nm within a milling period of 15 min is obtained. The deposition of the crushed material on a polypropylene thin‐film support is carried out by adding a cationic detergent, thereby obtaining a homogeneous and geometrically well defined droplet. The detergent quality and strength together with its correlation with the soil cation‐exchange capacity are discussed. Clayey and sandy soil samples from different soil profiles containing a wide range of organic materials were investigated. Samples of 0.5–1 mg cm −2 were analyzed by use of a monochromatic Mo Kα irradiation technique. The utility of the data fitting and quantification software X‐Spec32 is discussed. A brief comment is made on the environmental aspects of soil analysis, especially in relation to metal and mineral transport and distribution through the different types of soil and soil profiles.