For TXRF, the samples were measured for 200 s at X-ray fluorescence beam line
of the National Synchrotron Light
Laboratory (LNLS), Campinas, Brazil.
For excitation, a polychromatic beam with energy range 4 at 22 keV and
photon flux 3109 photons s1 at 8 keV was used which
was 2 mm wide and 1 mm high. In the X-ray detection
system, a Si (Li) detector with a resolution of 165 eV at 5.9
keV was used.