ANALYSIS OF FALSE-POSITIVE RESULTS AND THE REAL EFFECTIVENESS OF LUMINOL IN THE DETECTION OF BLOOD SPOTS.

Abstract

Forensic investigators have widely used luminol for more than 90 years in the identification of blood in life crime scenes. When mixed with an alkaline solution and sprayed on a catalyst (iron present in blood hemoglobin), it reproduces a chemiluminescent reaction with a bluish color. As it is a presumptive blood test, the present study sought to demonstrate that only the photons emission is not a prerogative to attest that the result is indeed human blood. In this perspective, 24 samples of both liquid and solid substances that can easily be found in residences and potentially used by criminals to impair the interpretation of the investigator at the crime scene were prepared. Out of the total of the analyzed samples, there was a chemical reaction with sodium hypochlorite and wood varnish, proving the known understanding that some samples may cause interference in the examination with luminol.