A real-time smartphone-enabled time since death estimation from vitreous humour protein

Abstract

This study reports on a smartphone-based application for the determination of time since death (TSD) from vitreous humour (VH) protein via recognition and quantification using a simple biuret method for on-the-spot analysis. In basic pH, in the presence of protein, the biuret reagent forms a protein-biuret complex resulting in a colour change that is measurable using a UV-vis spectrophotometer. The limit of detection (LOD) for Bovine serum albumin (BSA) was found to be 8 μg/ml and the limit of quantification (LOQ) was found to be 10 μg/ml. The developed method was further validated and applied for TSD determination from VH samples in the range of 3–60 h. The results showed that there is a linear correlation between the VH protein concentration and TSD, as the protein concentration decreases up to 60 h, with the equation TSD = 33.72 + (–0.27) × concentration. Further, in the present study smart approach was applied for the TSD determination. The results obtained showed that the current method proves to have a great utility up to 60 h. The linear regression equation between TSD and RGB (red, green and blue) intensities of protein concentration tup to 60 h ± 4.5 h was found to be TSD = 6.27E2+1.41*RGB intensity. The proposed method provides a smart, rapid and sensitive, as well as cost effective, TSD determination via VH protein.

Keywords:

• Time since death
• protein
• vitreous humour
• smartphone
• biuret
• forensic science

Acknowledgements

It would not have been possible to perform the study without the financial support of the Maulana Azad National Fellowship for minority students, University Grant Commission, India.