Multivariate Analysis Aided Surface-Enhanced Raman Spectroscopy (MVA-SERS) Multiplex Quantitative Detection of Trace Fentanyl in Illicit Drug Mixtures Using a Handheld Raman Spectrometer

Abstract

Recently there has been upsurge in reports that illicit seizures of cocaine and heroin have been adulterated with fentanyl. Surface-enhanced Raman spectroscopy (SERS) provides a useful alternative to current screening procedures that permits detection of trace levels of fentanyl in mixtures. Samples are solubilized and allowed to interact with aggregated colloidal nanostars to produce a rapid and sensitive assay. In this study, we present the quantitative determination of fentanyl in heroin and cocaine using SERS, using a point-and-shoot handheld Raman system. Our protocol is optimized to detect pure fentanyl down to 0.20 ± 0.06 ng/mL and can also distinguish pure cocaine and heroin at ng/mL levels. Multiplex analysis of mixtures is enabled by combining SERS detection with principal component analysis and super partial least squares regression discriminate analysis (SPLS-DA), which allow for the determination of fentanyl as low as 0.05% in simulated seized heroin and 0.10% in simulated seized cocaine samples.

Tailored Colloidal Nanostars for Surface-Enhanced Raman Spectroscopy: Optimization of Formulation Components and Study of the Stabilizer–Nanoparticle Interactions

“…Moreover, the NS/ CO 3 2− (c) formulation has already been successfully applied to the detection of such a class of analytes, both in standard solutions 85 and in binary mixtures of other abused substances. 86 While the effects of nanoparticle morphology are commonly reported in the literature, comparisons of different surface environments are less frequently explored. In our case, the effect of the surface environment was deemed more important than that of shape, encouraging further exploration of surface chemistry in the optimization of SERS-based analytical protocols.…”

“…Although these foundational experiments were all conducted utilizing CV as an ideal SERS probe, the superiority in performance was also verified with nonideal probes, such as the opioids acrylfentanyl and benzylfentanyl (Supporting Information). Moreover, the NS/CO 3 2– (c) formulation has already been successfully applied to the detection of such a class of analytes, both in standard solutions and in binary mixtures of other abused substances . While the effects of nanoparticle morphology are commonly reported in the literature, comparisons of different surface environments are less frequently explored.…”

Innovative Vibrational Spectroscopy Research for Forensic Application

“…To detect fentanyl in heroin at concentrations as low as 0.05% with a portable instrument, Wang et al even developed a SERS method. 211 A limit of detection for fentanyl as low as 0.001% was achieved by Wilson et al using portable SERS, and they identified fentanyl in mixtures with heroin and caffeine, a common diluent. 212 Gozdzialski et al illustrated the advantages of SERS over current immunoassay strips well.…”

“…Using a hand-held Raman spectrometer, Wang et al quantified fentanyl in illicit drug mixtures. 12 Mirsafavi et al utilized SERS to detect and classify fentanyl and its precursors. 217 These papers pave the way for the creation of a portable spectral library that would contain spectral information for fentanyl and its precursors.…”

“…This has afforded a large push for fast and safe methods to identify and quantify illicit substances. Researchers are working to develop the capabilities of portable spectroscopy instrumentation, allowing rapid and confirmatory on-site identification of drug samples, , thus allowing the rapid identification of the components within drug samples. To identify and differentiate body fluids, Raman and IR spectroscopies have been widely investigated in the forensic biology field during the last 14 years.…”