Abstract: Studies on the determination of trace impurities in ((Gd,U)O_2) were described. The bulk of the matrix U was separated by column extraction chromatography from its nitric acid solution using CL-TBP. The collected aqueous fraction containing the impurities and gadolinium was fed to an ICP-AES for determination using a new interference correction technique——multi-component spectral fitting(MSF). The studies also includes the setting up and validity testing of the MSF model, the recovery of impurities at various concentrations, etc. Based on the above studies, the methods were standardized for the determination of 29 elements, viz. Al,Ba,Ca,Co,Cr,Cu,Fe,Li,Mg,Mn,Mo,Na,Ni,Ti,Zn,Ta,W,Th,Bi,Pb,Sn,V,In,Ag,B,Cd,Sm,Eu and Dy in (Gd,U)O_2 samples. Similar levels of these elements in other uranium and/or gadolinium compounds can also be determined if they are treated and converted to the same aqueous fraction.