Probing menstrual bloodstain aging with fluorescence spectroscopy

Menstrual blood (MB) is a common and important type of forensic evidence, especially in sexual assault cases. MB is composed of peripheral blood (PB), vaginal fluid, and endometrial cells of the uterine wall. In forensic investigations, the differentiation of MB and PB can determine whether the blood present is a result of tissue damage from an assault or a natural cause and thus help to reconstruct the event. Understanding how menstrual blood changes is necessary to develop a method for bloodstain aging. Fluorescence spectroscopy, a promising spectroscopic method for bloodstain analysis, was used to probe the biochemical changes that occur over time in menstrual bloodstains. It was found that steady-state fluorescence spectra underwent significant changes over first nine hours post deposition. The underlying mechanism of fluorescence changes was proposed to involve the kinetic transformation of three fluorophores: tryptophan, nicotinamide adenine dinucleotide and flavins. (C) 2020 Elsevier B.V. All rights reserved.

Automated summary

Menstrual blood (MB) is a significant forensic evidence, consisting of peripheral blood, vaginal fluid, and endometrial cells. Understanding the changes and biochemical analysis of menstrual blood using fluorescence spectroscopy can help differentiate the cause of blood presence in forensic investigations, whether it is due to assault or a natural cause. The mechanism of fluorescence changes in menstrual blood involves the kinetic transformation of three fluorophores: tryptophan, nicotinamide adenine dinucleotide, and flavins.