Increased effectivity at the preparation of powder samples for the X-ray fluorescence analysis with the aid of the pressing technique

There are two main approaches to prepare powder samples as test specimens for X-ray fluorescence technique: (i) Preparation of measurable pellets with and without any binding agent, and (ii) Melting of the specimen with appropriate digesting agents to obtain a glassy smelt. The pellets prepared by means of the powder pressing technique with cellulose and polyvinyl alcohol as binding agents show deficiencies in the evacuation behaviour due to water adsorption. This shortcoming is being overcome by the use of polyethylene powder. In this contribution the following properties of the pellets prepared with the binding agents mentioned above are compared: mechanical strength, evacuation behaviour, homogeneity, sensitivity and costs. The test results indicate that polyethylene is well suited as a binding agent for the preparation of powder samples, its properties being superior to those of the binding agents so far generally used. (author)