The Ability to Affect the Results of a Phenolphthalein Test with Household Chemicals


  • Javier Moreno Texas A&M Univeristy


The detection of blood at a crime scene can yield great progress for an investigation. The presence of the bodily fluid can lead to the knowledge of whether the blood is in fact human, the amount of people that were present at the scene, and lead to DNA analysis being done and obtaining the identity of which the blood belongs to. A component in blood, hemoglobin, can break down hydrogen peroxide, making the protein a great focus for presumptive blood tests. For this experiment, a few household chemicals were used to test their ability to tamper with a color indicator Phenolphthalein Test. If the swab turned pink rapidly, this meant the stain came back positive for blood. If no color change occurred, the test could not detect if the substance swabbed was blood. Results obtained showed that household products with certain chemicals and percentage of said chemicals can be used denature the composition of hemoglobin in bloodstains.