This report presents the methodology and findings of a study that demonstrates the application of gold nanoparticles in using Surface Enhanced Raman Spectroscopy (SERS) to detect synthetic cannabinoids in saliva and urine.
As more synthetic cannabinoids become illegal, new legal analogs of these drugs are being made. This presents problems for hospitals and forensic investigators, since standard methods may not detect the target drug. The most common methods of screening for drugs of abuse in biological samples are based on immunoassays; however, these methods are based on bio-recognition elements, so they are sensitive to the molecular structure and geometry of the target analyte. This makes them intrinsically prone to the loss of specificity across drug analog generations. A potential solution is SERS. When Raman spectroscopy is performed in the presence of plasmonic nanostructures, the signal can be improved by several orders of magnitude by the excitation of the localized surface plasmon resonance (LSPR). This generates an electromagnetic field at the nanostructure surface that is much stronger than the one generated by the impinging Raman laser source., thus enabling the detection of trace analytes. The creation of hot spots due to the addition of aggregating agents further contributes to the improvement of the signal. In the current study, JWH-018 was used for testing SERS, because it is among the first to be designated as a Schedule I substance by the DEA, and it is one of the most studied synthetic cannabinoids in terms of toxicological concentrations in humans. The affinity between JWH-018 and the citrate-reduced gold nanoparticle substrate was quantified by studying their adsorption behavior. Based on the testing presented in this report, the researchers believe the proposed protocol could be useful in the quick detection of JWH-018 and other synthetic cannabinoids. Extensive figures and tables and 33 references