Raman spectroscopy approach rapidly identifies 'legal highs'

Raman spectroscopy can rapidly screen for and identify novel psychoactive substances (NPS), known commonly as "legal highs."

A team of researchers at Queen's University Belfast (Northern Ireland) turned to Raman spectroscopy to rapidly screen for and identify novel psychoactive substances (NPS), known commonly as "legal highs." The approach will now enable statutory agencies to identify the actual substances contained within legal highs more quickly, thereby enabling more prompt public health messages to be issued out to communities. The researchers also envision that the method will also help speed up related criminal prosecutions.

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When first produced, these "legal high" substances were not covered by existing drugs legislation, but they are now set to face a total ban effective April 6, 2016, when the UK government's new Psychoactive Substances Act comes into force. The ban covers (with the exception of a number of listed compounds such as alcohol, caffeine, etc.) "any substance intended for human consumption that is capable of producing a psychoactive effect," with those caught producing or supplying such drugs facing a maximum prison sentence of seven years.

Devised by Professor Steven Bell and PhD researcher Louise Jones in Queen's School of Chemistry and Chemical Engineering, the research team's method in line with the new ban combines rapid screening for known drugs with in-depth analysis of new compounds. The screening works by detecting the characteristic vibrations of the bonds within the samples by focusing a laser on the sample and measuring the energy of light scattering from it—a technique known as Raman spectroscopy. The vibrations are chemical signatures of the compounds, so when they have been recorded, they can be searched against a library of known compounds. They are then either identified as known compounds or marked as new variants that can then be taken for further analysis in the laboratory.

In the study, 75% of more than 200 previous samples seized by the Police Service of Northern Ireland (PSNI) could be identified immediately. In the future, the researchers hope that the method will allow for laboratory facilities to be freed up for in-depth investigation of those compounds identified as new and unknown.

The research team worked in conjunction with Forensic Science Northern Ireland and the work was funded by the Department of Justice's Asset Recovery Community Scheme, which uses assets seized from criminals. The next stage of the research will be working with live casework samples.

Full details of the work appear in the journal Analyst; for more information, please visit http://dx.doi.org/10.1039/c5an02326b.

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