Effectiveness of oxidizing reagents in removal of blood stains (PDF)

Academic Paper from the year 2019 in the subject Chemistry - Analytical Chemistry, grade: A, , language: English, abstract: This text is focussing on the effectiveness of oxidizing reagents in removal of blood stains. Adjustments, amendments, and concealing of the crime evidence have resulted in an increment in the world's crime rate. One such recurring hindrance can be seen with the most vital forms of evidence; bloodstains. Bloodstains are considered to be one of the most difficult stains to remove and even after cleaning them off the clothes through the detergents available in the market, there are some colored traces left which do not disappear completely and can be detected.

Forensic scientists use luminol to detect bloodstains which when reacted with iron in blood stains exhibit chemiluminescence. This led to thinking of to what extent were these criminals able to manage the escape by washing the stains and hinder the evidence. After researching about the detergents from journals and websites like "The Science of Stain Removal, Study of Oxyper- H2O2, and Study of sodium perborate" and also studying the effect of various compounds present in them, it was found out that the active oxygen reagents were the sources through which bloodstain removal was possible. This helped in framing a research idea: To what extent does the change in mass of the oxidizing reagent, sodium perborate, sodium percarbonate and hydrogen peroxide found in detergents is effective in removing bloodstains, measured by spectrophotometric analysis of change in chemiluminescence intensity of luminol due to the oxidation of ferrous to ferric ions in stock solution containing oxidizing agents and iron solution imitating blood at room temperature (30°C)? In this essay, the correlation between the removal of the stains and the extent to which it depends on the amount of reagent was measured.

The decrease in chemiluminescence signifies the extent to which the stains are removed. On this basis, the cleansing action of various oxidizing agents like hydrogen peroxide, sodium perborate, and sodium percarbonate was compared. Seeing the competence of the strongest oxidizing reagent, it can be considered that this research will be useful for forensic science departments to detect the extent to which evidence was tried to be concealed as all the oxidizing agents contain H2O2 and even after washing the clothes, some content of H2O2 is left. It will also be valuable for the detergent manufacturers because, through this research, they will opt for a better oxidizing agent to yield a better cleansing action.