FTIR and Raman spectroscopic characterization of cannabinoids

Tetrahydrocannabinol (THC), cannabidiol (CBD), and cannabinol (CBN) are three key phytochemical components of cannabis. All three have demonstrated phytochemical activity and are implicated in pharmacological use of cannabis. In this paper, we present the Fourier transform infrared and Raman spectroscopic characterization of THC, CBD, and CBN compounds obtained from certified reference materials. Spontaneous Raman, mid-infrared absorption spectra as well as the analogous surface-enhanced counterparts (surface-enhanced Raman spectroscopy and surface-enhanced infrared absorption) of the cannabinoids are discussed in detail here. We have also examined the laser induced photothermal changes that occur in THC and CBD under spontaneous Raman acquisition conditions as revealed in their Raman spectra. Vibrational spectroscopy provides a robust, portable, and cost effective analytical approach to quality control for various medicinal and consumer cannabinoid products. The pure compound spectra of the three cannabinoids presented in this work will help end-users to establish better quantitative analysis methods based on these techniques.