Blood, as a cardinal biological system, is a challenging target for biochemical characterization because of sample complexity and a lack of analytical approaches. To reveal and evaluate aging process of blood compositions is an unexplored issue in forensic analysis, which is useful to elucidate the details of a crime. Here we demonstrate a spectral deconvolution model of near-infrared Raman spectra of bloodstain to comprehensively describe the aging process based on the chemical mechanism, particularly the kinetics. The bloodstain spectra monitored over several months at different temperatures are decomposed into significant spectral components by multivariate calculation. The kinetic schemes of the spectral components are explored and subsequently incorporated into the developed algorithm for the optimal spectral resolution. Consequently, the index of bloodstain aging is proposed, which can be used under different experimental conditions. This work provides a novel perspective on the chemical mechanisms in bloodstain aging and facilitates forensic applications.

血液作为主要的生物系统，由于样品的复杂性和缺乏分析方法，是生化表征中具有挑战性的目标。揭示和评估血液成分的老化过程在法医分析中尚待探讨，这对于阐明犯罪细节非常有用。在这里，我们展示了血渍的近红外拉曼光谱的光谱去卷积模型，以基于化学机理，特别是动力学来全面描述衰老过程。通过多变量计算将在不同温度下几个月监测的血迹光谱分解为重要的光谱成分。探索了光谱成分的动力学方案，随后将其纳入为最佳光谱分辨率而开发的算法中。所以，提出了血渍老化指数，可以在不同的实验条件下使用。这项工作为血迹老化的化学机理提供了新颖的视角，并促进了法医学的应用。