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Bloodstain Degradation and Time Since Deposition Estimation Using Electrochemistry

Amber Williams

Blood is an essential sort of forensic evidence because it may be used to identify sources, perform toxicological investigations, and evaluate bloodstain patterns. Determining the time of bloodshed, often known as the bloodstain's time since deposition (TSD), has significant consequences for crime scene investigation. In this paper, we use differential pulse and hydrodynamic voltammetry to monitor the progressive oxidative changes and electron-transfer reactions of haemoglobin (Hb) that occur in decaying bloodstains. Bloodstains were seen during a two-week period in five distinct temperature conditions. According to linear mixed models derived from Differential Pulse Voltammograms (DPV), 7 out of 27 variables linked to the redox processes connected with the blood film were substantially correlated with time (p 0.033). All of the linked variables were related to the binding of oxygen to haemoglobin or the oxidation of haemoglobin breakdown products inside the film. When haemoglobin is aged on an electrode surface, it keeps its catalytic activity for oxygen reduction, with a shift to higher peroxide generation as the age increases. When the biological replication is treated as a random effect and peak area ratios are incorporated in the model, time series models improve. Interestingly, independent of temperature setting, we detected a significant shift in redox response at the 96-h time point (p 0.043) using linear mixed models. Overall, we provide early support for DPV as a strategy for estimating TSD in bloodstains.