Estimation of the age of human bloodstains by electron paramagnetic resonance spectroscopy: Long-term controlled experiment on the effects of environmental factors

In search of blood—Detection of minute particles using spectroscopic methods

“…Several attempts have been made in the past to estimate the age of blood by means of spectroscopic methods, such as spectrophotometry [4] and EPR spectroscopy [11]. These methods are only valid in a controlled laboratory environment and large errors can be made when using these on samples which may have been exposed to unknown external influences.…”

Age estimation of blood stains by hemoglobin derivative determination using reflectance spectroscopy

“…Already in the 1930s Schwarzacher attempted to correlate the age of a blood stain with the blood stain's rate of inhibition of solubility in water, which begins rapid and then decreases slowly as the blood stain ages [1]. Over the last two decades, many more techniques have been explored for this forensic quest, including oxygen electrodes [2], RNA degradation [3], atomic force microscopy [4], and electron spin resonance spectroscopy [5]. Although all of these approaches confirm that the physical and chemical properties of blood stains change over time, no technique has yet shown the precision and reproducibility that is needed for age determination in forensic practice.…”

Gender-related difference in bloodstain RNA ratio stored under uncontrolled room conditions for 28 days

“…Research on bloodstain aging has included chemical assays, 9 enzyme assays, 10 and many methods utilizing deteriorative changes in the visible spectrum of hemoglobin (Hb) over time. 11e14 Several new approaches have recently been introduced: High Performance Liquid Chromatography (HPLC), 15,16 Atomic Force Microscopy (AFM), 17 Electron paramagnetic Resonance Spectroscopy (EPR), 18,19 Diffuse Reflectance Spectroscopy (DRS) 20 and others. All of these methods have limited effectiveness with either weak age correlation or specific sample type or size constraints, and may be adversely influenced by environmental factors.…”