Accurate diagnosis, monitoring and treatment are cornerstones of a healthcare system and require reliable measurements. The traceability of measurement results to stated references, and the development of Reference Measurement Systems (RMS), provide mechanisms to achieve the required consistency of results. The primary standards within such an RMS are of pure substance certified reference materials. Developments in modern measurement and mass spectrometric techniques have opened up the possibility to characterize and quantify more complex large molecules such as peptides, enabling RMS to be developed for these analytes.

The prohormone angiotensin I is a hypertension biomarker and was selected as a model peptide. The full mass balance approach, the peptide impurity corrected amino acid analysis, elemental analysis and quantitative nuclear magnetic resonance approaches have been investigated and optimized to compare the performance of these different methodologies for the purity mass fraction value assignment of an ANG I calibrator material.

准确的诊断，监视和治疗是医疗保健系统的基石，需要可靠的测量。测量结果对指定参考的可追溯性以及参考测量系统（RMS）的开发提供了实现所需结果一致性的机制。此类RMS中的主要标准是纯物质认证的参考材料。现代测量和质谱技术的发展为表征和定量更复杂的大分子（例如肽）开辟了可能性，从而使这些分析物的RMS得以开发。

原激素血管紧张素I是高血压的生物标志物，被选作模型肽。已对全质量平衡法，肽杂质校正的氨基酸分析法，元素分析法和定量核磁共振法进行了研究和优化，以比较这些不同方法对ANG I校准物材料的纯度质量分数值分配的性能。