43
The SFC Isolation and Purification of Cannabinoids using Application Specific Stationary Phases Under Optimised Conditions
by Matthew Przybyciel, PhD and David A. Kohler, ES Industries 701 South Route 73, West Berlin, NJ 08055 USA
Cannabis sativa is comprised of hundreds of individual compounds that can be classified in many chemical families, such as terpenes, amino acids, fatty acids, hydrocarbons, flavonoids, sugars and cannabinoids [1,2]. Cannabinoids represents a class of chemicals that are classified as terpenophenolic compounds. There are about 70 terpenophenolic compounds in the cannabinoid class. These are only found in cannabis plants [3]. Of the 70 cannabinoids found in Cannabis there are several cannabinoids that are of human physiological and medicinal interest [4]. These include the psychoactive ∆-9-tetrahydrocannabinol (THC), non-psychoactive cannabidiol (CBD) and the non-psychoactive tetrahydrocannabivarin (THCV) (5-8). THC, THCV and CBD are neutral forms of cannabinoids, obtained after a non-enzymatic decarboxylation of delta 9-tetrahydrocannabinolic acid (THCA), tetrahydrocannabivarinic acid (THCVA) and cannabidiolic acid (CBDA). It is the focus of this manuscript to utilise SFC chromatographic stationary phases that have been specifically developed for the isolation and purification of THCA, CBDA, THC, CBD and THCV. These specific cannabinoids require the use of several different stationary phases for optimised separation and purification of them individually.
Supercritical fluid chromatography (SFC) is a powerful chromatographic technique for the separation and isolation of complex mixtures from natural products. It has been useful in the area of preparative chromatography [9-11]. Virtually all current practitioners of SFC use carbon dioxide (CO2
) which offers
several advantages when compared to preparative liquid chromatography [12]. The use of carbon dioxide (CO2
) as the
primary component of the mobile phase is one of the key features that benefits preparative SFC chromatography since the CO2
used for SFC is considered a ‘Green’ solvent. It is miscible with a wide range of organic solvents, nonflammable, has low UV absorbance at short wavelengths [13-15]. CO2
SFC is particularly well suited
in the area of preparative chromatography where it can be easily removed enabling the rapid recovery of isolated compounds.
Figure 1: Separation of 10 cannabinoids chromatographed on GreenSep NP-I, a coated polysaccharide stationary phase.
In addition, any residual amounts of CO2 in isolated products are considered to be non-toxic [16]. Another advantage of SFC as a technique is that the diffusion coefficient of solutes in the SFC mobile phases have been shown to be 3-10 times higher than in normal liquids potentially allowing for very rapid separations. In addition the viscosity of SFC mobile phases are significantly lower than LC mobile phases hence producing a much lower pressure drop across the column
Page 1 |
Page 2 |
Page 3 |
Page 4 |
Page 5 |
Page 6 |
Page 7 |
Page 8 |
Page 9 |
Page 10 |
Page 11 |
Page 12 |
Page 13 |
Page 14 |
Page 15 |
Page 16 |
Page 17 |
Page 18 |
Page 19 |
Page 20 |
Page 21 |
Page 22 |
Page 23 |
Page 24 |
Page 25 |
Page 26 |
Page 27 |
Page 28 |
Page 29 |
Page 30 |
Page 31 |
Page 32 |
Page 33 |
Page 34 |
Page 35 |
Page 36 |
Page 37 |
Page 38 |
Page 39 |
Page 40 |
Page 41 |
Page 42 |
Page 43 |
Page 44 |
Page 45 |
Page 46 |
Page 47 |
Page 48 |
Page 49 |
Page 50 |
Page 51 |
Page 52 |
Page 53 |
Page 54 |
Page 55 |
Page 56
