Digestion with aqua regia in Carius tube is commonly employed for determination of PGEs in geological samples. However, silicates cannot be completely dissolved by aqua regia and PGEs might partially remain in silicate residue. In this study, an ultramafic reference material was used to investigate the efficiencies of a new re-usable Carius tube after digestion at 220 and 240 , and an autoclave ℃ -lined Carius tube at 260 and 280 . The results show ℃ that about 10% of PGEs retained in the silicate residues at 220 and 5% still r ℃ emains even digestion temperature increases to 280 . These results agree with previous works that increasing the digestion pressure and temperature ℃ can achieve more effective dissolution. Thus, a modified digestion procedure for determination of PGEs in ultramafic rocks by the re-usable Carius tube was proposed in this study