The study by Weis et al. (2006) provides a comprehensive and systematic analysis of the isotopic compositions (Sr, Nd, and Pb) of a wide range of U.S. Geological Survey (USGS) reference materials, including various types of volcanic rocks. The research utilized both TIMS (Thermo Electron, Finnigan Triton) and MC-ICP-MS (Nu Instruments Plasma) to achieve high precision and accuracy in isotopic measurements. The results show that the first- and second-generation USGS reference materials have homogeneous Sr and Nd isotopic compositions, with minimal differences between the two generations. However, significant differences in Pb isotopic compositions and concentrations were observed between the first and second generations, indicating contamination during sample processing. Leaching experiments on selected reference materials confirmed the presence of contamination, particularly in the form of trace elements such as Li, Mo, Cd, Sn, Sb, and W. The study highlights the importance of proper sample preparation and the need for leaching to remove contamination, especially for Pb isotopic analyses, which require higher precision and accuracy. The findings provide valuable insights into the reliability and homogeneity of USGS reference materials for scientific research.The study by Weis et al. (2006) provides a comprehensive and systematic analysis of the isotopic compositions (Sr, Nd, and Pb) of a wide range of U.S. Geological Survey (USGS) reference materials, including various types of volcanic rocks. The research utilized both TIMS (Thermo Electron, Finnigan Triton) and MC-ICP-MS (Nu Instruments Plasma) to achieve high precision and accuracy in isotopic measurements. The results show that the first- and second-generation USGS reference materials have homogeneous Sr and Nd isotopic compositions, with minimal differences between the two generations. However, significant differences in Pb isotopic compositions and concentrations were observed between the first and second generations, indicating contamination during sample processing. Leaching experiments on selected reference materials confirmed the presence of contamination, particularly in the form of trace elements such as Li, Mo, Cd, Sn, Sb, and W. The study highlights the importance of proper sample preparation and the need for leaching to remove contamination, especially for Pb isotopic analyses, which require higher precision and accuracy. The findings provide valuable insights into the reliability and homogeneity of USGS reference materials for scientific research.