d Chemistry in Crime Investigation: Sodium Percarbonate Effects on Bloodstains Detection

Chemistry plays a leading role in crime investigation. In the study of bloodstains, chemical reactions provide the means for the detection. All these procedures have been thoroughly studied. However, recently, a new source of error has been found: washing stains with active oxygen detergents abrogates presumptive and human hemoglobin tests for bloodstains (although visible). The aim of this investigation was to evaluate the ability of pure sodium percarbonatemain component of detergentsto abrogate presumptive and human hemoglobin tests. Then, a solution to this problem could be found. The results demonstrate that pure sodium percarbonateitselfis able to abrogate all tests, as well as the different degrees to which each of them is affected by the product. Consequently, faced with a stain of bloody appearance, even the preliminary tests are negative; it is advisable to analyze the DNA. Otherwise, the opportunity of obtaining valuable information is lost.