Applicability of liquid and supercritical fluid chromatographic separation techniques with diode array ultraviolet detection for forensic analysis

Liquid chromatography (LC) and supercritical fluid chromatography (SFC) are powerful separation techniques for forensic science in the analysis of drugs, toxicology samples, trace evidence, and explosives. Combining LC and SFC with diode array detectors (DAD) can provide detection at a single wavelength or generate complete UV spectra. This advantageous pairing within forensic science allows distinguishing between classes and subclasses of compounds, discriminating positional isomers with benzene substitutions, and using library database comparison to enhance certainty of compound identification through statistical comparison. Additionally, employing DAD at single wavelengths and generation of UV spectra allow quantitation with excellent linearity, good linear range, and satisfactory limits of detection. Important for quantitation, the generation of UV spectra allows confirmation of compound identity and peak purity. The purpose of this article is to provide an overview of the qualitative and quantitative uses of LC, and SFC paired with scanning DAD within forensic science over the last ten years (2010-2020), including the analysis of seized drugs, toxicology samples, explosives, inks, and dyes. Potential benefits, limitations, and future directions for liquid phase separation paired with ultraviolet detection are considered.