title: Surface enhanced Raman spectroscopy (SERS) as a method for the toxicological analysis of synthetic cannabinoids.
abstract: Synthetic cannabinoids (K2, spice) present problems in forensic investigations because standard presumptive methods, such as immunoassays, are insufficiently specific for the wide range of potential target compounds. This issue can lead to problems with low sensitivity and yield false negative results. A potential solution to this problem is surface enhanced Raman spectroscopy (SERS). In this study we demonstrate the analysis of a set of structurally similar synthetic cannabinoids using SERS. The procedure involves mixing the analyte with gold nanoparticles prepared in a solution containing alkali or alkaline earth salt solutions. The salts produce aggregation of the nanoparticles with a resultant spectral enhancement due to the formation of spectral hotspots with enhanced field effects within the aggregate. Among the salts tested, 0.0167M MgCl2produced the lowest limit of detection and best overall sensitivity. The method produces clearly distinguishable spectra for each synthetic cannabinoid with detection limits as low as 18ng/mL. Spiked urine samples were also analyzed following a cleanup procedure involving support liquid extraction. When using a portable Raman system, a higher concentration of MgCl2was needed to produce similar a LOD. The results demonstrate that this procedure has great potential as a method for presumptive screening of synthetic cannabinoids.
authors.affiliation: Department of Chemistry, Florida International University, 11200 SW 8th Street, CP304, Miami, FL 33199, USA.
authors.forename: Thaddeus
authors.initials: T
authors.lastname: Mostowtt
authors.affiliation: Department of Chemistry, Florida International University, 11200 SW 8th Street, CP304, Miami, FL 33199, USA. Electronic address: mccordb@fiu.edu.
authors.forename: Bruce
authors.initials: B
authors.lastname: McCord
mesh_terms: D002186:Cannabinoids / Q000032:analysis* / Q000737:chemistry; D006046:Gold / Q000737:chemistry; D057230:Limit of Detection; D015636:Magnesium Chloride / Q000737:chemistry; D053768:Metal Nanoparticles / Q000737:chemistry; D013059:Spectrum Analysis, Raman / Q000379:methods*; D014116:Toxicology
chemical_list: D002186:Cannabinoids; D015636:Magnesium Chloride; D006046:Gold
keywords: SERS; Surface enhanced Raman spectroscopy; Synthetic cannabinoids; Toxicology