Deep ultraviolet Raman spectroscopic analysis of antihistamine drugs in oral fluid for forensic purposes

Owing to its inherent nondestructive nature, rapid analysis and simplicity, Raman spectroscopy has emerged as a promising tool for forensic analysis of different bodily fluids, particularly oral fluid (OF). Accurate drug identification and quantification are essential for understanding the circumstances surrounding a case, such as whether it involves an overdose fatality, substance abuse, or drug trafficking. This study aims to evaluate the potential of using deep ultraviolet Raman spectroscopy (DUVRS) to detect the antihistamine cetirizine (CTZ) in liquid and solid OF samples. The application of DUVRS facilitated CTZ detection in liquid OF samples with a limit of detection (LOD) of 50 µg/mL. Additionally, integrating multivariate statistical analysis with DUVRS enabled reliable differentiation between pure OF stains and those contaminated with CTZ, thereby demonstrating its high sensitivity for CTZ detection. Further method development is warranted, involving larger cohorts of donors, increased numbers of samples, and a broader range of drug types, to enhance the practicality of this approach for forensic applications.