The Role of Vibrational Spectroscopy in Identifying Species from Body Fluids: A Review

Species identification from different biological fluids is an important task for forensic practitioners in cases involving animal abuse or wildlife offences. Various presumptive and confirmatory assays are available and provide valuable information, but they have some limitations, such as false-positive results and incompetence in degraded samples. In recent years, vibrational spectroscopy has emerged as a promising, nondestructive method for the successful identification of body fluids at the molecular level. Blood, among all body fluids, has been studied the most, and vibrational spectroscopy, when coupled with chemometric techniques such as principal component analysis and partial least squares-discriminant analysis, has shown great accuracy in species identification. Next to blood, urine is less extensively studied, but it has shown potential for identifying metabolites. Saliva and tears are rich in biochemical composition but remain unexplored in vibrational spectroscopic analysis for species identification, though preliminary examination suggests species-specific molecular signatures. This review explores the advantages and limitations of current approaches for body fluid identification. It also reviews the current and future aspects of spectroscopic methods when coupled with chemometrics, which offer a rapid, sensitive, noninvasive platform for species identification from body fluids.