An analytical method for the determination of trace metal elements in crude oils by inductively coupled plasma tandem mass spectrometry(ICP-MS/MS)was established.Combining cluster analysis(CA),a discriminant model was established to trace the origin of crude oil in the different regions.The mass fractions of 18 trace metal elements including Mg,Al,Ti,V,Cr,Mn,Fe,Co,Ni,Cu,Zn,Rb,Sr,Mo,Ag,Cd,Ba and Pb in crude oil samples were determined by ICP-MS/MS after microwave digestion.In the MS/MS mode,polyatomic interferences on the lighter mass elements c...