conditions was recorded, meaning that this is more pronounced when the samples
were exposed to light at 22 °C. As expected, the content of CBN increased during
storage and the increase is higher when the samples were exposed to light at 22 °C
(Trofin et al. 2012 ).
Turner et al. (1973a, b), recorded the decomposition of D^9 -THC content of
Cannabis sativaL. stored at−18.0, 4.0, and 22.0 °C at a rate of 3.83, 5.38, and 6.92%,
respectively, per year, whereas the material stored at 37 and 50 °C showed consider-
able decomposition. The storage inthe absence of direct light at−18.0,4.0,and22.0°
C was more stable than cannabis stored under nitrogen. These data indicated that for
normal research use, storage under nitrogen at 0 °C is not mandatory. Cannabinol is not
the only decomposition product of (-)-D^9 -THC. Evidence supported the possible for-
mation of hydroxylated hexahydrocannabinol intermediates as a decomposition prod-
ucts in storedC. sativaL (Turner et al.1973a,b).
7.5 Analysis of Cannabinoids in Cannabis and Cannabis
Products
Gas chromatography (GC), High Performance Liquid Chromatography (HPLC),
Ultra Pressure Liquid Chromatography (UPLC), and High Performance Thin Layer
Chromatography (HPTLC) techniques have been used to determine cannabinoids
in cannabis plant material and cannabis products. Those methods are different in
their applications, level of sensitivity and specificity.
7.5.1 Gas Chromatography (GC)
Gas Chromatography is the most common technique for the analysis of cannabi-
noids, it is simple, fast and sensitive for the determination of the total cannabinoids
(neutral and acidic) but it does not permit the determination of acidic cannabinoids
unless chemical derivatization is performed, such as preparation of trimethylsilyl
ethers, which requires extra processing steps.
In 2016, ElSohly et al. reported GC/FID quantitative analysis of cannabinoids in
illicit cannabis products (Marijuana, Sinsemilla, Thai sticks, Ditchweed, Hashish, and
Hash Oil) seized by the U.S. Drug Enforcement Administration over 20 years. During
this period 38,681 samples of cannabis preparations were examined with special
emphasis on the levels of seven cannabinoids (D^9 -THC,D^8 -THC, CBD, CBC, CBG,
CBN, and CBL). Using a validated GC/FID method on DB-1MS columns (15 m
0.25 mm0.25lm), injector temperature, 240 °C; detector temperature, 270 °C;
oven program, 170 °C (hold 1 min) to 250 °C at 10 °C/min (hold 3 min); run time,
12 min; injection volume, 1lLand4–androstene-3,17-dione was used as the internal
standard. The method was fast, sensitive, precise and accurate (ElSohly et al.2016a,b).
7 Natural Cannabinoids of Cannabis and Methods of Analysis 175