Raman spectroscopy in forensic analysis: identification of cocaine and other illegal drugs of abuse

Abstract

*Current forensic methods for detecting and identifying cocaine and other drugs of abuse are destructive, so evidence cannot be re-analyzed. Raman spectroscopy, based on inelastic light scattering, allows for rapid, inexpensive and nondestructive analysis in forensic science. This review presents the state-of-the-art use of Raman spectroscopy as a confirmatory method for the identification of cocaine and other drugs of abuse in seized samples, including hidden compounds in legal materials such as beverages and clothes, among others, used for trafficking. Quantitative Raman spectroscopy is used to determine the actual drug concentrations in street cocaine and crack rocks and to identify possible adulterants in these samples for forensic toxicology and criminalistics. Finally, recent developments in Raman spectrometers (portable instruments and new excitation wavelengths) and advancements in data analysis offer exciting opportunities for new applications of Raman spectroscopy in the identification and quantification of drugs of abuse, including investigations conducted immediately at the scene of a crime.

Modified PCA and PLS: Towards a better classification in Raman spectroscopy–based biological applications

“…Raman spectroscopy saw dramatic growth in biological applications in the last two decades, thanks to its features: label‐free, noninvasive, and almost insensitive to water . Raman‐based studies have covered a large variety of biological fields, including but not limited to toxicology and forensics, microbiology, drug discovery, metabolic investigations, and even in vivo detection . Notably, Raman spectroscopy has found its place in process analytical technology (PAT); for example, it was employed to optimize ethanol fermentation .…”

A penetrating Raman probe with self‐referencing capability

“…In particular, the use of Raman spectroscopy in cancer detection has received increasing attention in recent years . Additionally, it may also find utility in the sensing of soil contaminants and the practice of forensics . By way of illustration, here we describe the acquisition of the Raman spectrum from the interior of porcine fat with our penetrating probe and show how the emission intensity can be measured in a quantitative manner.…”

Raman Spectroscopic Differences between Ephedrine and Pseudoephedrine

“…Raman spectroscopy offers benefits for first‐pass evaluation screening of potential compounds with forensic relevance because this technique requires small amounts of compounds (micrograms to milligrams) and minimum sample preparation. Raman spectroscopy has been preferentially used in many forensic studies, for example, for testing drugs and investigating the finger nails of drug‐abuse suspects .…”