Energy dispersive x-ray fluorescence analysis of thin and intermediate environmental samples

Energy-dispersive x-ray fluorescence (EDXRF) was applied to the analysis of environmental samples, such as algae, microalgae and marine sediments, prepared as thin samples by mixing powder with two-component epoxy resins, and as intermediate samples in the form of pellets. Further, sulphur, the concentration of which is used as an index of degradation, was analyzed ill situ on a 16th century mural painting inside the church of S. Stefano Rotondo in Rome. Finally, lead was monitored in air samples from the city of Lecce and a map of the Pb distribution at various locations in the city was obtained. The equipment for EDXRF analysis is based on miniaturized x-ray tubes (Oxford, 30 kV, 0.1 mA, Mo or Pd anodes; or Hamamatsu, 10 kV, 0.3 mA, Ca anode) and on thermoelectrically cooled Si-PIN detectors, having an energy resolution of 250 eV at 5.9 keV. Lead was excited,vith a Gilardoni x-ray tube (Radiolight, 80 kV, 5 mA, W anode and Mo secondary target) and x-rays were detected with an HpGe detector with an energy resolution of 160 eV at 5.9 keV. (C) 1998 John Wiley & Sons, Ltd.