Black and green tea — Luminol false-negative bloodstains detection

The antioxidant properties of black and green teas are well known. It is also possible to determine their antioxidant capacity by using a chemiluminscent method. This method is based on the measurement of the delay in the emission of light from the luminol reaction in the presence of the antioxidant. Bloodstains which are invisible to the naked eye can also be detected by luminol. Three common methods (detection using the Grodsky or Weber formulations and by Bluestar® Forensic latent bloodstain reagent) are based on the luminol chemiluminescence reaction. The bloodstains can be masked by drinks and/or foods containing antioxidants. The aim of this work was to compare the ability of black and green teas containing antioxidants to cause false negative results during chemiluminescent bloodstain detection.