7.5.2 High-Performance Liquid Chromatography (HPLC)
High-Performance Liquid Chromatography (HPLC) does not affect the structure of
the cannabinoids since no heat is applied, which permits analysis of both neutral
and acidic cannabinoids. However, it has the disadvantage of possible insufficient
resolution of the whole array of cannabinoids due to the complex composition of
plant material extracts.
A validated HPLC method was used for the analysis of THCA, CBDA, THC,
CBD, CBG, CBC,D^8 -THC, and CBN in two cultivars of cannabis from California.
Separation was achieved on a Poroshell 120 EC-C18 column (2.7lm,
150 2.1 mm i.d., using PDA and 214 nm for quantification. Gradient eluent
consisted of 0.1% formic acid in water (solvent A) and 0.1% formic acids in
acetonitrile (solvent B). Ibuprofen was used as internal standards. Selectivity, lin-
earity, accuracy (recovery and percentage relative bias), and repeatability precision
(RSDr) of the method were determined. This method provided baseline resolution
of the 8 cannabinoids in 17 min (Giese et al. 2015 ).
Quantification of eleven cannabinoids, in three different varieties of cannabis as
well as in seizures made by the Drug Enforcement Administration (DEA) was
performed at the University of Mississippi using a validated HPLC method. The
cannabinoids includedΔ^9 -THC,Δ^8 -THC, CBG, CBC, CBD, CBDA, CBL, CBN,
THCV, THCAA, and CBGA. The cannabinoids were separated on on a Luna C18
(2) column (1504.60 mm i.d., 3lm particle size. The mobile phase consisted of
(A) 0.1% (v/v) formic acid in water and (B) 0.1% (v/v) formic acid in acetonitrile
with gradient elution program. UV spectra were recorded from 210 to 400 nm and
the quantification wavelength was set at 220 nm. Run time was 22.2 min. the
method was described as accurate, fast and reliable and could be used for routine
analysis of cannabis (Gul et al. 2015 ).
Recently, Wang et al. determined the concentrations of three cannabinoids,
D^9 -THC, CBD, and CBN in 13 cannabis edible and beverage samples. The samples
include baked goods, chocolate bars and hard candies. LC-MS/MS was used in the
positive electrospray ionization mode (ESIMS) and C18 HPLC column
(100 mm2.1 mm 3 μparticle size) column. The mobile phase consists of
10 Mm ammonium acetate and methanol with 0.1% formic acid in a gradient
manner. The method was described as QuEChERS (Quick, easy, cheap, effective,
rugged and safe) (Xiaoyan Wang et al. 2016 ).
A manual prepared by the United Nations, Division of Narcotic Drugs
(UNODC) has described an HPLC method for the analysis of CBD, CBN, THC and
THCA in homogenous herbal cannabis using 250 mm4.0 mm RP-8 (5μm)
column and an isocratic mobile phase [Acetonitrile: water (8:2 v/v)]. The total run
time was 8 min. The quantitation was carried out at two wave lengths of 220 and
240 nm (UNODC 2009 ).
The American Herbal Pharmacopeia (AHP) choose a validated HPLC/DAD
method developed by De Backer et al. for qualitative and quantitative determination
ofΔ^9 -THC, THCA, CBD, CBDA, CBG, CBGA, CBN, andΔ^8 -THC in eight
7 Natural Cannabinoids of Cannabis and Methods of Analysis 177