A search for the best separation of eighteen cannabinoids, the maximum number of cannabinoids that have been quantified so far, using liquid chromatography diode array detector (LC-DAD) was conducted, for potency testing of hemp-based products. The study focused on two different types of LC columns with the same inner diameter, i.e., 2.1 mm, same size of core-shell particles, i.e., 2.7 µm, but varied stationary phases, i.e., traditional diisobutyl-octadecyl (Raptor ARC-18) and RP (reversed-phase)-carbamate (Cortecs Shield RP-18). The resolution of adjacent cannabinoids was kept close to 1.5 or higher, while the separation time was kept as short as possible, achieving 15.0 and 20.0+7.0-min (two complementary separations) using Raptor ARC-18 and Cortecs Shield RP-18, respectively. Furthermore, a 7.0-min separation was obtained for potency testing of hemp-based products by liquid chromatography electrospray ionization tandem mass spectrometry (LC-ESI/MS/MS) using Cortecs Shield RP-18. The polarity differences of the stationary phases had significant effects on the retention factor and selectivity of CBG/CBD/THCV, Δ9-/Δ8-THC, CBC/CBT, and most acidic cannabinoids.
(Publisher abstract provided.)