Date of Award
Bachelor of Science
In the field of forensics, blood is considered a highly useful tool. DNA found in blood is currently viewed as the best source of identifying a suspect; however, DNA analysis is mainly used as a comparative method. DNA analysis can single out a suspect they are physically present in custody or if a match is made through a database of stored profiles, such as the Combined DNA Index System (CODIS).1-3 There are new methods of DNA analysis that can identify a person of African/Caribbean decent, hair and eye color, and even the age of a person.4-6 However, this DNA analysis is complex, time consuming, and expensive compared to the biocatalytic-analysis of enzyme, protein, or metabolite levels in blood that can be done quickly, while still determining similar attributes of a blood sample originator.7 Using spectrophotometric analysis of a newly designed bioaffinity-based assay of the enzyme alkaline phosphatase, the relative age of a blood sample originator can be distinguished with high accuracy. Alkaline phosphatase (AP) is an enzyme that is commonly used in clinical diagnostics because it is essential to bone growth.8-9 Due to its role in growing bones, AP is present in higher levels in people who are younger. The difference in AP levels between someone who is growing, or “young”, and someone who is no longer growing, or “old”, can be determined using the enzymatic reaction of AP with p-nitrophenol phosphate. Results achieved in this experiment show that this system can be used, even after real human serum samples were exposed to mimicked crime scene conditions for up to 48 hours. Additionally, the experimentation done proved that the time since deposition (TSD) of a blood sample at a crime scene could also be determined using the newly developed assay. The information extracted from this novel assay could potentially help police narrow down the suspect pool, and with further advancements it could even be used on-site at a crime scene in order to provide quick and accurate distinctions.
Rodrigues, Roselyn, "Proof of Concept for the Forensic Analysis of Blood Spots to Distinguish Time Since Deposition and Relative Age of Blood Spot Originator" (2016). Chemistry. 7.