Discrimination between human and animal blood by attenuated total reflection Fourier transform-infrared spectroscopy

Abstract

Forensic chemistry is an important area of analytical chemistry. This field has been rapidly growing over the last several decades. Confirmation of the human origins of bloodstains is important in practical forensics. Current serological blood tests are destructive and often provide false positive results. Here, we report on the development of a nondestructive method that could potentially be applied at the scene for differentiation of human and animal blood using attenuated total reflection Fourier transform-infrared (ATR FT-IR) spectroscopy and statistical analysis. The following species were used to build statistical models for binary human–animal blood differentiation: cat, dog, rabbit, horse, cow, pig, opossum, and raccoon. Three other species (deer, elk, and ferret) were used for external validation. A partial least squares discriminant analysis (PLSDA) was used for classification purposes and showed excellent performance in internal cross-validation (CV). The method was externally validated first using blood samples from new donors of species used in the training data set, and second using donors of new species that were not used to construct the model. Both validations showed excellent results demonstrating potential of the developed approach for nondestructive, rapid, and statistically confident discrimination between human and animal blood for forensic purposes.

Attenuated total reflection-Fourier transform infrared spectroscopy: a universal analytical technique with promising applications in forensic analyses

“…Later on, these findings were validated by the same research team on a wider group of species. The team tested stains of bloods of twelve species including human, domestic and wildlife animals [66]. The potential application of ATR-FTIR in discriminating between stains of bloods of different species was further confirmed in a relatively recent study carried out in 2018.…”

“…ATR-FTIR has emerged as an accurate and nondestructive analytical method for the detection and differentiation between stains of blood of different species. The potential applications of this technique in the forensic analysis of bloodstains have been outlined in several studies [52,55,58,60,[62][63][64][65][66]. Here below, we presented a detailed review of these studies based on the type of information that can be deduced from the analysis.…”

“…Despite the conclusion made by De Wael and his team, research continued to investigate the potential use of ATR-FTIR in differentiating between stains of bloods of different species. Multiple studies used ATR-FTIR in combination with chemometric to achieve this purpose [52,63,64,66]. In 2015, Mistek et al showed that ATR-FTIR spectroscopy can be used jointly with PLS-DA to differentiate between bloodstains prepared from human and animal bloods.…”

Identification of blood species based on surface‐enhanced Raman scattering spectroscopy and convolutional neural network

“…In 2009, I. K. Lednev group reported the effective distinction between human and animal blood (dog blood and cat blood) with the identification rate of 99%. Since then, their research group conducted a series of studies [7][8][9][10][11][12][13][14], and in 2018, they expanded animal species to 16, achieved a 99% identification rate between human and animals using partial least squares discriminant analysis (PLS-DA) [13]. In 2017, J. Fujihara reported the discrimination of human blood from non-human blood based on analysis of 11 blood Raman spectra using principal component analysis (PCA) [15].…”

Attenuated Total Reflection Fourier Transform Infrared Spectroscopy for Forensic Screening of Long-Term Alcohol Consumption from Human Nails

“…Fourier transform infrared (FT-IR) spectroscopy has been utilized as an analytical technique for numerous applications in the forensic field. FT-IR spectroscopy has been applied to a wide range of types of evidence, and it performed well in the examination of questioned documents found at a crime scene, paints, banknotes, fibers, hair, , gunshot residue analysis, and body fluid traces. − The nondestructive nature of this method enables us to utilize the same portion of the sample for further examination. This method is rapid, nondestructive, and quantitative, which are ideal properties for forensic analysis.…”