The particle-induced X-ray emission (PIXE)-alpha portable spectrometer of the Laboratori Nazionali del Sud has been upgraded to improve X-ray energy resolution and efficiency. A value of 124 eV at Mn Κα-line and a factor of 3 were, respectively, achieved. These enhanced capabilities allowed the thin surface examination of 5 Roman nummi, in which previous near-surface X-ray fluorescence measurements revealed traces of mercury. In particular, the new version of the PIXE-alpha spectrometer has allowed the distinction of the 2.19 keV Hg M-line from the 2.30 keV S K-line and the 2.34 keV Pb M-line. Subsequent elemental association has demonstrated a correlation between surface mercury and silve