Raman Spectroscopy
of Blood for Species Identification
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Abstract
The
species identification of a blood stain is an important and
immediate challenge for forensic science, veterinary purposes, and
wildlife preservation. The current methods used to identify the species
of origin of a blood stain are limited in scope and destructive to
the sample. We have previously demonstrated that Raman spectroscopy
can reliably differentiate blood traces of human, cat, and dog (Virkler et al. Anal. Chem. 2009, 81, 7773−7777) and, most recently, built a binary model
for differentiating human vs animal blood for 11 species integrated
with human existence (McLaughlin
et al. Forensic Sci. Int. 2014, 238, 91−95). Here we report a satisfactory classification of blood obtained
from 11 animal classes and human subjects by statistical analysis
of Raman spectra. Classification of blood samples was achieved according
to each sample’s species of origin, which enhanced previously
observed discrimination ability. The developed approach does not require
the knowledge of a specific (bio)chemical marker for each individual
class but rather relies on a spectroscopic statistical differentiation
of various components. This approach results in remarkable classification
ability even with intrinsically heterogeneous classes and samples.
In addition, the obtained spectroscopic characteristics could potentially
provide information about specific changes in the (bio)chemical composition
of samples, which are responsible for the differentiation