Cannabidiol and tetrahydrocannabinol concentrations in commercially available CBD E-liquids in Switzerland

Cannabidiol (CBD) rich hemp and hemp products low in Δ⁹-tetrahydrocannabinol (THC) (less than 1%) are legally available in Switzerland. Besides herbs for smoking and oils, liquids (e-liquids) for smoking in electronic cigarettes (e-cigs) have recently appeared on the market. These e-liquids are available with different CBD concentrations and can be flavoured. The aim of the current study was to investigate 20 e-liquids legally available in Switzerland for their contents using Fourier-transform infrared spectroscopy (FTIR) as a preliminary step followed by gas-chromatography coupled to mass spectrometry to identify potential cannabinoids, natural plant compounds and flavours. Quantification of CBD, cannabidiol carboxylic acid (CBD-acid), cannabinol (CBN), Δ⁹-tetrahydrocannabinol (THC), and Δ⁹-tetrahydrocannabinol carboxylic acid A (THC-acid) was performed by a validated method with ultra-high-pressure-liquid chromatography coupled to a diode array detector (UHPLC-DAD). FTIR analysis could confirm that for all investigated samples the e-liquid matrix consisted of 1,2-propanediol and glycerol. The qualitative GC-MS could identify ten phytocannabinoids including the quantified analytes, six natural plant compounds and five flavours. All analysed samples had a total THC content below 0.1059% (by weight), hence meeting the legal requirements of both Switzerland (<1%) and the European Union (<0.2%). The total CBD content ranged from 0.182 to 3.346% and differed in ten out of 20 samples from the CBD content presented by the manufacturer by more than 10% relative CBD. Furthermore, two of the analysed samples contained only 0.348% and 0.182% total CBD despite being labelled as "CBD rich". Seven of the 20 samples contained the correct CBD content (in the range of the labelled CBD content ± 10%). In conclusion, a deviation in the determined total CBD content from the labelled CBD content could be observed for half of the analysed samples, meaning that consumers cannot rely on the manufacturers' information. It is remarkable, that currently no official regulations for providing correct information of CBD content or any external product control is available in Switzerland and in most other countries.