同位素稀释热电离质谱法测定人血清中痕量铜和锌

采用热电离同位素稀释质谱法(ID-TIMS)准确测定了欧盟标准物质与测量研究院(EC-JRC-IRMM)组织的国际测量评估计划IMEP-17人血清样品中的痕量铜和锌。由于锌和铜都是易受污染的元素,本工作建立了仅用少量硝酸消解的低流程本底和适于热电离质谱测量的生物基体血清中痕量铜和锌的样品前处理方法;采用适当比例的硅胶和磷酸作为电离增强剂,在热电离质谱(TIMS)测量时获得了较高强度且稳定的铜和锌离子束;血清中痕量铜和锌的测量结果可直接溯源到国际单位mole。2种人血清样品中铜和锌测量结果的不确定度(k=2)分别为0.94%、0.83%和0.49%,测量值被EC-JRC-IRMM采用作为该样品的标准值。

Accurate Determination of Trace Copper and Zinc in Human Serum by Isotope Dilution-Thermal Ionization Mass Spectrometry

Isotope dilution-thermal ionization mass spectrometry (ID-TIMS) was used to examine the certified copper and zinc contents in the human serum samples of International Measurement Evaluation Programme-17 launched by EC-JRC-IRMM. The chemical preparation methods for copper and zinc in serum were studied in terms of reducing procedure blank and fitting measurement of TIMS. A silica gel and H_3PO_4 ionization enhancement technique was used for copper and zinc isotope ratios analysis owing to their high ion potentials. The stable and high ion beam intensities of copper and zinc were obtained when measuring isotopic ratios by TIMS. The measurement results of copper and zinc in the serum samples able to trace to SI unit-mole with 0.94%, 0.83% and 0.49% combined uncertainty respectively, were accepted by IRMM as the certified values of the serum samples.