Physikalisch-Technische Bundesanstalt, Bundesallee 100, 38116 Braunschweig, Germany.
Anal Bioanal Chem. 2013 Feb;405(6):1913-9. doi: 10.1007/s00216-012-6315-x. Epub 2012 Aug 15.
Triple isotope dilution mass spectrometry (triple IDMS) has been applied for the first time on protein quantification, especially on transferrin. Transferrin as an acute phase protein is a marker for several inflammation processes in the human body. Therefore, in Germany, the accurate and precise measurement of this important analyte is required. In this work, a new approach to triple IDMS is described and compared to double IDMS. Also, complete uncertainty budgets for both methods were set up to demonstrate the ability of this method to be used as a reference procedure. The relative expanded uncertainty (k=2) for triple IDMS (3.6 %) is smaller than the one for double IDMS (4.0 %). The content of transferrin found in the human serum reference material ERM-DA470k/IFCC ((2.41±0.08) g/kg) with both methods was in good agreement with each other and with the certificate. For triple IDMS ((2.426±0.086) g/kg) and for double IDMS ((2.317±0.092) g/kg), transferrin was determined. Although triple IDMS is a little more time consuming compared to double IDMS, there is the advantage that the isotopic composition of the spike material does not have to be determined. This is very useful especially in case of a marginal isotopic enrichment in the spike or problems with the accurate measurement of the spike isotope ratio.
三重同位素稀释质谱法（triple IDMS）首次应用于蛋白质定量，特别是转铁蛋白。转铁蛋白作为一种急性期蛋白，是人体中几种炎症过程的标志物。因此，在德国，需要对这种重要分析物进行准确、精密的测量。在这项工作中，描述了一种新的三重 IDMS 方法，并与双 IDMS 进行了比较。此外，还为这两种方法建立了完整的不确定度预算，以证明该方法可作为参考程序使用。三重 IDMS 的相对扩展不确定度（k=2）（3.6%）小于双 IDMS 的相对扩展不确定度（4.0%）。用两种方法测量人血清参考物质 ERM-DA470k/IFCC 中的转铁蛋白含量（（2.41±0.08）g/kg），结果彼此一致，与证书一致。用三重 IDMS （（2.426±0.086）g/kg）和双 IDMS （（2.317±0.092）g/kg）都测定了转铁蛋白。尽管三重 IDMS 比双 IDMS 稍微耗时，但它具有一个优势，即不必确定加标物质的同位素组成。这在加标物的同位素丰度稍有富集或加标同位素比值的准确测量存在问题的情况下非常有用。
