Synchrotron radiation total reflection for rainwater analysis

Total reflection X-ray fluorescence analysis excited with synchrotron radiation (SR-TXRF) has been used for rainwater trace element analysis. The samples were collected from four different sites at Campinas City, SP, Brazil. Standard solutions with gallium as internal standard were prepared for the calibration system. Rainwater samples of 10 μl were added to Perspex reflector disks, dried under vacuum and analyzed for 100 s measuring time. The detection limits obtained for K-shell lines varied from 29 ng ml−1 for sulfur to 1.3 ng ml−1 for zinc and copper, while for L-shell the values were 4.5 ng ml−1 for mercury and 7.0 ng ml−1 for lead.