Quantifying chemiluminescence of the forensic luminol test for ovine blood in a dilution and time series

Abstract

This study investigates the chemiluminescent reaction of whole ovine blood with a luminol solution in a time and dilution series. Replicate samples of both fresh and dried certified pathogen-free ovine blood were prepared and diluted. Seven dilution conditions from neat to 1:1000000 were created for testing. A luminol solution, created using the standard Weber protocol, was applied to all samples in controlled laboratory conditions. A SpectraMax^® M3 microplate reader luminometer was used to quantify the chemiluminescence from the reactions as relative luminescence units (RLUs) every four seconds for three minutes. Trends within and amongst the times series, reaction half-lives, and maximum chemiluminescent intensities are discussed. Our research provides a comprehensive dataset derived from instrumental and visual observations on the chemiluminescence resulting from ovine blood's reaction to luminol. This study has implications in forensic bloodstain pattern analysis as it offers a mixed method approach to characterizing the reaction between blood and a commonly used presumptive testing reagent.

Keywords: Bloodstain pattern analysis; Chemiluminescence; Ddiluted blood; Luminometer; Presumptive testing; Time series.