Multielement Analysis of Rubber Samples by X-Ray Fluorescence

Destructive elemental analysis of rubber samples for major and trace element constituents is a rather demanding task, mainly because of the need for sophisticated and time-consuming sample preparation procedures. X-ray analysis has so far been used in the rubber industry primarily as a rapid tool for qualitative analysis, but a more realistic estimate of the accuracy of this, in many aspects, advantageous technique indicates that it could qualify as a quantitative method. In this work rubber samples were analyzed by the X-ray fluorescence analysis (XRFA) technique, utilizing Cd-109 and Fe-55 for excitation radioactive sources. The quantification procedure used employed a minimum number of calibration steps, utilizing only single-element-thick standards and stable compounds, or standard reference materials. Matrix correction calculations employed known fundamental constants and absorption measurements on a particular sample. In order to validate the results, and to establish the accuracy of analysis, some samples were also analyzed by neutron activation analysis (NAA). For the same purpose, the analysis of some standard reference materials of biological and inorganic matrices were performed. The accuracy of 5 to 6% achieved by XRFA means that it should be considered in the rubber industry as a rapid, simple, and cheap alternative to the analytical methods usually adopted.