Rappold Brian A, Hoofnagle Andrew N
Essential Testing, Collinsville, IL 62234, United States.
Department of Laboratory Medicine, University of Washington, Seattle, WA 98195-7110, United States.
Clin Mass Spectrom. 2017 Apr 30;3:13-21. doi: 10.1016/j.clinms.2017.04.002. eCollection 2017 Jan.
Mass spectrometry provides considerable benefits over other analytical techniques due to advantages imparted by the use of isotopically labeled internal standards. In some analytical approaches, the internal standard provides reference points for quantitative data reduction. However, there is an important phenomenon that occurs in the development of an internal standard, namely the distribution of naturally occurring isotopes is altered by artificial labeling. As a result, the number of molecules measured in each isotopic state (e.g., +0, +1, +2) varies between the manufactured internal standard and the naturally occurring unmodified analyte. This can create inaccuracies that are a function of the abundance, type and location of the isotopic labeling when internal standards act as the calibration material. In this study, theoretical examples calculated with naturally occurring isotopic incorporation, manufactured isotopic enrichment, and experimental data from comparative analysis of naturally and artificially labeled peptides were explored to demonstrate the variation in measurement between analytes and their stable, isotopically labeled internal standards.
由于使用同位素标记的内标物带来的优势，质谱分析相对于其他分析技术具有显著的优势。在某些分析方法中，内标物为定量数据处理提供参考点。然而，在内标物的开发过程中会出现一个重要现象，即人工标记会改变天然存在的同位素的分布。结果，在每个同位素状态（例如，+0、+1、+2）下测量的分子数量在人工合成的内标物和天然存在的未修饰分析物之间有所不同。当内标物用作校准材料时，这会产生与同位素标记的丰度、类型和位置相关的误差。在本研究中，通过天然存在的同位素掺入、人工合成的同位素富集计算出的理论示例，以及天然和人工标记肽的比较分析的实验数据，来探讨分析物与其稳定的、同位素标记的内标物之间测量值的差异。
