| The 27 elements in recycled oils and edible vegetable oils were analyzed by inductively coupled plasma mass spectrometry (ICP-MS) to determine the differences in the 27 elements contents in recycled oils and edible vegetable oils, and identify recycled oils from normal edible vegetable oils. The samples of 22 qualified edible vegetable oils and 120 recycled oils were collected,and the contents of 27 elements were analyzed by ICP-MS after microwave digestion. The element content difference analysis was carried out using partial least squares discriminant analysis to identify specific elements between different types of recycled oils and edible vegetable oils.The results showed that Co，Cu，Fe，Na and Mn were very different between crude recycled oils and edible vegetable oils，which could be used to identify crude recycled oils. The contents of Fe and Cd were very different in refined recycled oils and edible vegetable oils, which could be used to identify refined recycled oils. The contents of Cr, Cd, Ag, Ca, Pb, Hg and Al were significantly different in refined recycled oils with different color，which could guide the further extraction and refining, and the reuse of crude bio-oil according to the level of its element content.The results could provide a reference for the identification of recycled oils from edible vegetable oils. |
