Leaner and greener analysis of cannabinoids
Leaner and greener analysis of cannabinoids
Elizabeth M. Mudge 0 1
Susan J. Murch 0 1
Paula N. Brown 0 1
0 Department of Chemistry, University of British Columbia , 3247 University Way, Kelowna, British Columbia V1V 1V7 , Canada
1 Natural Health & Food Products Research, British Columbia Institute of Technology , 3700 Willingdon Ave, Burnaby, British Columbia V5G 3H2 , Canada
There is an explosion in the number of labs analyzing cannabinoids in marijuana (Cannabis sativa L., Cannabaceae) but existing methods are inefficient, require expert analysts, and use large volumes of potentially environmentally damaging solvents. The objective of this work was to develop and validate an accurate method for analyzing cannabinoids in cannabis raw materials and finished products that is more efficient and uses fewer toxic solvents. An HPLC-DAD method was developed for eight cannabinoids in cannabis flowers and oils using a statistically guided optimization plan based on the principles of green chemistry. A singlelaboratory validation determined the linearity, selectivity, accuracy, repeatability, intermediate precision, limit of detection, and limit of quantitation of the method. Amounts of individual cannabinoids above the limit of quantitation in the flowers ranged from 0.02 to 14.9% w/w, with repeatability ranging from 0.78 to 10.08% relative standard deviation. The intermediate precision determined using HorRat ratios ranged from 0.3 to 2.0. The LOQs for individual cannabinoids in flowers ranged from 0.02 to 0.17% w/w. This is a significant improvement over previous methods and is suitable for a wide range of applications including regulatory compliance, clinical studies, direct patient medical services, and commercial suppliers.
Green chemistry; Single-laboratory validation; Cannabis; Cannabinoids; Medical marijuana
* Paula N. Brown
The modern cannabis market is in a period of dramatic flux. In
the USA, cannabis is classified as a schedule I drug , but eight
US states have legalized marijuana for recreational use and 28
states have allowed medical marijuana on the basis of evidence
of anxiolytic, analgesic, sedative, anticancer, and appetite
stimulation effects [2–5]. Regulations regarding Cannabis spp. vary
globally. The Netherlands, Uruguay, and Portugal have
decriminalized possession. In Canada, cannabis is a schedule II
controlled substance, but regulations have allowed production
for medical purposes through licensed producers and personal
production licenses . Canadian production of commercial
products must take place in a facility using good manufacturing
practices, and products must be assayed for the presence and
quantity of Δ9-tetrahydrocannabinol (Δ9-THC),
Δ9tetrahydrocannabinolic acid (THCA), cannabidiol (CBD), and
cannabidiolic acid (CBDA), using validated analytical methods
. In total, more than 100 cannabinoids in 11 subclasses have
been characterized in cannabis and are concentrated in the
glandular trichomes of the female inflorescences and other
cannabinoids classes include cannabigerols (CBG), cannabichromenes
(CBC), and cannabinols (CBN) (Fig. 1) . The cannabinoids
occur primarily in acid form, with neutral cannabinoids formed
during drying, storage, and decarboxylation during smoking.
Δ9-THC, the main psychoactive cannabinoid, can be over
20% by weight in specially bred cannabis strains [8, 9]. CBD,
known for its anti-inflammatory activity and antagonism of
Δ9THC-induced anxiety, can range from below 0.5% up to 6.5% by
weight [9, 10].
Fig. 1 Structures for the main neutral cannabinoids found in Cannabis
There are a significant number of analytical methods to
quantify cannabinoids available, many of which do not
provide sufficient validation data to establish the method
performance and reliability. Without this information,
there is a possibility that the methods are not fit for
purpose. The solvent composition, mass to solvent ratio,
extraction technique and time vary considerably between
methods. Separations of cannabinoids use different
mobile phases, columns and gradients, and given the number
of minor cannabinoids present in authentic materials,
there is a possibility for co-elution of peaks and
inaccurate quantitative results [11, 12]. Rigorous validation
procedures are necessary to ensure that the results of any
analytical method are reliable. Without this data on
method performance, the final method may not meet the needs
of the users who adopt it for routine use, therefore
producing inaccurate information pertaining to the products
that people are using for the treatment of medical
conditions . The speed with which regulations have
changed and the nature of the rapidly expanding cannabis
marketplace have created increased pressure for fast, safe,
simple, and accurate analysis of phytochemicals to meet
the demands of high-throughput laboratories and rapid
release of finished products.
The most commonly used extraction solvent for
cannabinoid analysis is 9:1 methanol/chloroform (% v/v), with
some exceptions [9, 11, 14–16]. It was originally selected
to dissolve the internal standard di-n-octyl phthalate,
which is no longer necessary with commercially available
reference standards . There is an increasing desire to
find greener methods to reduce use of chlorinated solvents
which can be toxic, expensive to dispose of, and
hazardous to transport and store [17, 18]. Long-term,
chronic exposure to chloroform is associated with liver
and kidney damage, where the occupational exposure
limit is 2 ppm in air [18, 19]. While laboratory safety
procedures reduce exposure significantly, the risks of spills and
inhalation of vapors are increased with chloroform use
and there is a diversity of safety equipment used in the
labs engaged in this analysis. Removal of chloroform
from the extraction solvent will improve laboratory safety,
reduce reagent and disposal costs, while improving the
environmental impact associated with chlorinated solvent
The objective of the current work was to develop a fully
validated, simplified, green chemistry method for labs to
implement that may not have high levels of expertise or capacity
for method development or validation. We developed the
method using statistically guided method development
protocols for the quantitation of eight cannabinoids in Cannabis
flowers and oils. Nine authentic Cannabis flower materials
and one Cannabis oil with a wide range of cannabinoid
contents were obtained and used as test articles for the validation
of the method of the AOAC International guidelines . This
method does not use chlorinated solvents, reduces sample
preparation time, and ensures precise and accurate
determination of cannabinoids.
Materials and methods
HPLC-grade methanol and acetonitrile were purchased from
VWR International (Mississauga, ON, Canada). ACS-grade
chloroform was obtained from VWR International. Water
was purified to 18 MΩ using a Barnstead Smart2Pure
nanopure system (Thermo Scientific, Waltham, MA).
Ammonium formate for HPLC (>99.0%) was purchased from
Sigma Aldrich (Oakville, ON, Canada) and formic acid was
(98% pure) was purchased from Fisher Scientific (Ottawa,
Certified reference materials (CRMs) were purchased from
Cerilliant Corp (Round Rock, TX) for nine cannabinoids:
Δ9-THC, THCA, Δ8-THC, CBD, CBDA, CBG, CBN,
CBC, and tetrahydrocannabivarin (THCV). The individual
cannabinoids were provided in solution at 1.0 mg/mL
concentration certified by the supplier. The acidic cannabinoids were
provided in acetonitrile and neutral cannabinoids in methanol.
Fresh ampules were used for the validation study to ensure
accurate quantitation of the individual constituents.
Table 1 Concentration of
cannabinoids used in the
calibration standards for the
method validation and resolution
of analytes in chromatographic
Approximate Concentration (μg mL−1)
*Between component of interest and closest eluting peak
Dried medical marijuana samples were purchased from
several licensed producers within Canada. Nine products were
selected for a variety of cannabinoid concentrations ranging
from 0.2% to 17% total THC and 0.3% to 9% total CBD.
As a result of the legal restrictions pertaining to these
products, voucher specimens were not possible, but were
purchased directly from the source to ensure authenticity. A dried
ethanol extract was dissolved in oil at a 1:10 dilution.
An Agilent 1200 RRLC system equipped with a
temperaturecontrolled autosampler, binary pump, and diode array detector
(Agilent Technologies, Mississauga, ON, Canada) was used
to separate the cannabinoids. The separation was achieved on
a Kinetex® C18, 1.7 μm, 100 × 3.0 mm i.d. column
(Phenomenex, Torrance, CA). Mobile phase compositions
were (A) 10 mM ammonium formate, pH 3.6 and (B)
acetonitrile using gradient conditions at 0.6 mL/min. The separation
was achieved according to the following gradient: 0–8 min,
52–66%B; 8–8.5 min, 66–70%B; 8.5–13 min, 70–80%B; 13–
15 min, 80%B. A 7-min column equilibration was performed
after each run. The injection volume was 5 μL and detection
was at 220 nm. The autosampler was maintained at 4 °C.
Preparation of test materials
Plant tissues A minimum of 5 g of dried flowers was ground
together from each test sample to ensure sample homogeneity.
Ground flowers were extracted by weighing 200.0 mg into a
50-mL amber centrifuge tube. Then 25.00 mL of 80%
methanol was added and vortexed for 30 s. Extraction took place
using a sonicating bath for 15 min where samples were
vortexed every 5 min. Extracts were filtered with 0.22-μm
Teflon filter, diluted either 1:2, 1:5, or 1:10 using the
extraction solvent into amber HPLC vials, and stored at 4 °C
Oil Cannabis oil was mixed by inversion prior to sample
preparation. Then 50.0 mg of oil was weighed into a 50-mL
amber centrifuge tube to which 10.00 mL of methanol was
added and vortexed for 30 s. Extracts were sonicated for
15 min with vortexing every 5 min. Samples were filtered with
0.22-μm Teflon filters into amber HPLC vials and stored at
4 °C until analysis.
Analyte stability Mixed calibration standards were stored at
−20 °C, 4 °C, and 22 °C in the dark and tested at regular
intervals to assess cannabinoid stability in solutions. Sample
extracts were stored at 4 °C and 22 °C in light and dark
conditions. A sample with greater than 5% loss from time zero
was considered unstable.
Fractional factorial The partial factorial design for method
optimization and data analysis was completed using Minitab
16 (Minitab 16, State College, PA). Individual cannabinoids
were quantified as percentage weight for weight in Cannabis
flowers and milligrams per gram in oil. Microsoft Excel
(Richmond, WA) was used for quantitative calculations and
statistical analysis of validation data.
Single-laboratory validation parameters
The optimized method was subjected to a single-laboratory
validation according to AOAC International guidelines for
dietary supplements . Δ8-THC was not observed in any
of the samples and therefore was not considered in the method
25 mL:100 mg
9 Extraction Extraction Solvent Solvent
Time Technique Volume:Mass Composition
Fig. 2 Variation of total cannabinoids determined using a two-level
partial factorial design to optimize the sample preparation
Preparation of calibration solutions Individual cannabinoid
CRMs were used to prepare seven-point standard calibration
curves for eight cannabinoids in concentrations ranging from
0.5 to 250 μg/mL. Dilutions of the CRMs were performed
using the extraction solvent composed of 80% methanol.
Concentration ranges were modified for each cannabinoid as
summarized in Table 1. The calibration curves were plotted
and the slope and y intercept for each cannabinoid were used
for linear regression analysis. Calibration curves were visually
inspected and correlation coefficients were determined. An r2
of at least 0.995 was deemed suitable for quantitation. Mixed
standards were stored at 4 °C and were stable for up to 3 days.
Selectivity Selectivity was demonstrated by injecting the
reference materials and raw flower extracts to evaluate the
resolution between closely eluting peaks and potential
interferences at 220 nm. Resolution of greater than 1.5 is deemed
acceptable by AOAC guidelines . Peak purity was verified
for all cannabinoids of interest.
Repeatability and intermediate precision Quadruplicate
samples of each test material were prepared on a single day
to evaluate the repeatability as relative standard deviation (%
RSD) for the individual cannabinoids. Intermediate precision
was determined by repeating the repeatability studies on three
separate days. The within-day, between-day, and total
standard deviations were calculated for each cannabinoid in each
test material. HorRat values were calculated to assess the
overall precision of the method .
Recovery Recovery was determined at three concentration
levels of the major cannabinoids: CBDA, CBD, THCA, and
THC. Ground stinging nettle, used as the negative recovery
material, was spiked with individual cannabinoids and
prepared according to the sample preparation protocol.
Limits of detection and quantitation The limits of detection
and quantitation were determined using the US Environmental
Protection Agency (EPA) method detection limit (MDL)
Fig. 3 Optimization of a green chemistry extraction protocol.b
Concentration of the four major cannabinoids comparing a solvent
composition and volume to mass ratio, b extraction times of 15 min,
30 min, and 60 min, c short extraction times of 5 min, 10 min, 15 min,
and 15 min with vortexing every 5 min. (n = 3)
protocol . The MDL is defined as the minimum
concentration of substance that can be measured and reported with 99%
confidence that the analyte concentration is greater than zero.
Extract solutions containing low concentrations of the
cannabinoids were used to evaluate the method limits. Seven replicates
were injected and the calculation for MDL was determined as the
standard deviation of the calculated concentration between the
seven replicates multiplied by the t statistic at 99% confidence
interval. LOQ was determined as 10 times the standard deviation
for the replicates to determine the MDL.
A statistically guided optimization plan was developed using a
partial factorial design to determine the impact of four
parameters used in cannabinoid extractions from dried flowers.
Extraction of tissues Two levels were selected for each
factor: solvent composition (80% methanol, 9:1
methanol/chloroform), extraction technique (sonication, wrist action
shaking), extraction time (15 min, 1 h), and solvent volume
(10 mL, 25 mL). An initial prescreening of solvents indicated
that the extraction efficiency of methanol/chloroform mixture
was not different from 80% methanol allowing further studies
to use the greener option. The statistical analysis of these data
indicated that solvent volume was the most significant factor,
followed by solvent composition (Fig. 2). Extraction
technique and time did not affect the extraction of cannabinoids.
Further studies evaluating the solvent volume to mass and
solvent composition using 25 mL extraction solvent with
100 and 200 mg of sample confirmed that 200 mg was
equivalent to 100 mg, without saturating the extraction solvent
(Fig. 3a). The mass to volume ratios used previously range
considerably. In some cases, the mass of sample was as high
as 100 mg in 1 mL, up to 500 mg in 100 mL [11, 23].
Although extraction time did not significantly impact the
resulting cannabinoid content, it was optimized to increase
sample throughput. The factorial design showed slightly
lower total cannabinoids at 60 min in comparison with 15 min,
potentially indicating some degradation during long
extractions. Three time points were assessed: 15, 30, and 60 min.
The level of cannabinoids was not significantly different
between the time points (Fig. 3b). It was then verified if
Fig. 4 HPLC separation of a
standard mixture of cannabinoid
standards and b Cannabis flower
extract at 220 nm
extraction time could be reduced by evaluating 5, 10, and
15 min in comparison with 15 min with vortexing every
5 min. Again, no significant differences were observed
between all four extraction times, while 15 min with vortexing
was significantly higher than 5 min (Fig. 3c). These data were
used to formulate an optimized standard operating protocol
(see Electronic Supplementary Material, ESM) using
200 mg of dried flowers with 25 mL of 80% aqueous
methanol for 15 min by sonication with vortexing every 5 min.
Extraction of oils The extraction method was also optimized
for cannabis oil comparing (a) 9:1 methanol/chloroform as
used in the UNODC method for cannabis products , (b)
80% methanol, and (c) 100% methanol. These data show that
80% methanol was not sufficient for extracting the
cannabinoids in an oil matrix, but 100% methanol was equivalent to
the methanol/chloroform mixture. The final optimized
standard operating protocol (see ESM) for cannabis oil samples
was 50 mg of oil extracted with 10 mL of methanol using the
same extraction parameters as the dried flowers.
Stability The stability of cannabinoids was assessed to
determine whether losses occur prior to analysis that may
significantly affect the quantitative data. Mixed calibration standards
prepared in 80% methanol were stored at −20 °C, 4 °C, and
22 °C in the dark. Variations of less than 5% were considered
stable and acceptable. Significant changes in the cannabinoids
were found after 30 h at room temperature with THCA/CBDA
contents decreasing by 6.3 and 9.6%, respectively, while
mixed standards stored at −20 °C were degraded after 48 h
with THCA and CBDA contents reduced by 8.1 and 10.6%,
respectively. The standards were stable at 4 °C for the duration
of the 72-h study. Sample extracts were prepared with 80%
methanol and stored at 22 °C in light and dark conditions.
Under these conditions, THCA and CBDA were considered
unstable by 24 h into the study, with reductions of 6.7% for
both, resulting in 8–10% increases in the neutral forms of
these cannabinoids. Reductions of 11–23% of acidic
cannabinoids occurred under light conditions within 24 h. On the
basis of these findings an additional study was performed to
evaluate extract stability in 80% methanol and 9:1 methanol/
chloroform stored in the dark at 22 °C and 4 °C. The 9:1
methanol/chloroform extracts were found to be stable at
22 °C and 4 °C for the duration of the study, 36 and 48 h,
respectively, while 80% methanol at 4 ° C was stable for 48 h.
The extracts in 80% methanol were not stable at room
temperature for 24 h, similar to the previous study. The
elimination of chloroform from the extraction solvent improves
analyst safety, reduces solvent costs, and maintains cannabinoids
contents; therefore 80% methanol is a viable alternative
Table 2 Repeatability and
intermediate precision for
cannabinoid quantitation in
Cannabis dried flowers
ID # CAN001
ID # CAN002
ID # CAN003
ID # CAN004
ID # CAN005
ID # CAN006
ID # CAN007
ID # CAN008
ID # CAN009
Table 3 Repeatability and
intermediate precision for
cannabinoids in Cannabis oil
ID # CANOIL
*Cannabinoids below LOQ are not reported
extraction solvent for analytical quantitative analysis with the
use of a dark, temperature-controlled autosampler.
Optimized chromatography Several HPLC columns,
phases, dimensions, mobile phases, and gradients were
compared in preliminary experiments to determine a method for
baseline separation of as many cannabinoids as possible while
maintaining a short separation time. The optimal column used
for separation of cannabinoids was a Phenomenex Kinetex
core shell C18 column with sub-2.0-micron particle size.
This required an HPLC system capable of pumping above
400 bar, but a 600-bar instrument was sufficient. Mobile phase
pH appeared to be a significant factor in cannabinoid
separation; as pH decreases, retention of cannabinolic acids
increases, while at higher pH the retention decreases with poor
peak shape. By optimizing the pH of the aqueous mobile
phase for the separation to 3.6, it was possible to separate
THCA from other cannabinoids, while maintaining adequate
peak shapes. The final methodology was a 15-min analytical
run time with 10 mM ammonium formate pH 3.6 and
acetonitrile as the mobile phase as shown in Fig. 4. Resolutions of
major cannabinoids were greater than 2.0, while minor
components were greater than 1.70 using the mixed calibration
standards. Sample extracts were used to confirm resolution
during the validation study.
Linearity The seven-point calibration curves used on each day
of the validation were linear on visual inspection. The correlation
coefficient (r2) for each cannabinoid was greater than 99.5% for
all calibration curves on each day of the analysis, as summarized
in Table 1. The plots of residuals were random, confirming that
linear functions were suitable for cannabinoid concentrations up
to 250 μg/mL. Concentrations of CBDA in the high-THC
products CAN004 and CAN007 were lower than the lowest
concentration standard used in the validation study. In this case, the
materials are outside the calibration range of the method. If
samples are known to have lower concentrations, the calibration
curves can be adjusted to match the materials, therefore allowing
for quantitation within the calibration range. In this case, a
calibration range from 2.5 to 50 μg/mL would be sufficient for
quantitation. One additional standard would be necessary to run
in this case, and a lower concentration range curve could be
generated independent of the typically employed curve from 5
to 250 μg/mL.
Selectivity The chromatographic profiles of Cannabis
extracts at 220 nm were used to evaluate peak resolution. The
peak resolutions for the eight cannabinoids quantified with
this method ranged from 1.64 to greater than 2.0 as specified
in Table 1; in accordance with AOAC guidelines for dietary
supplements and natural products, a resolution greater than
1.5 is sufficient for quantitation given the complexity of
natural products . Sample extracts were used to evaluate peak
purity and confirm resolution with minor peaks. Peak purity
was greater than 99% for all cannabinoids evaluated in this
Repeatability Repeatability was assessed by quantifying the
eight minor and major cannabinoids for which standards were
available. The quantitative data from the four replicate
samples on day 1 were used to determine method repeatability. All
precision measurements used authentic Cannabis materials
with a range of cannabinoid concentrations. The repeatability
data are summarized in Table 2. Repeatability RSDs ranged
Table 5 Method detection limit
and limit of quantitation of
cannabinoids in solution and their
respective concentrations in dried
flowers using the EPA MDL
Amt in sample (% w/w)
Amt in sample (% w/w)
from 0.78 to 10.08%. For materials with higher than 0.5%
w/w cannabinoid content, the % RSDs ranged from 0.78 to
7.64%; only two of these materials had RSDs greater than 5%.
Given that the precision for seven of the nine materials
evaluated was less than 5% for the analytes above 0.5% w/w, it is
possible that the results for the two materials with greater than
5% RSDs are due to inherent variability of the cannabinoids
within these two test samples, rather than an indication of
method performance. This is likely due to a higher inherent
variability compared with the other strains used in the study.
The RSDs over 5% for all other materials were observed for
low level cannabinoids, for which small variations in the
quantitative data will have more of an impact on the %
RSDs. These values are within acceptable validation limits
based on their concentrations .
Intermediate precision The quantitative data from the four
replicates on the 3 days of analysis were used to calculate
the within-day, between-day, and total standard deviations
to determine the intermediate precision of the method.
Intermediate precision ranged from 2.07 to 11.67%
RSD, as summarized in Table 2. The HorRat ratios used
to determine the acceptability of the % RSDs based on
concentration ranged from 0.5 to 2.0, which is the
acceptable range as specified by AOAC International guidelines
. The HorRat ratios ranged from 0.3 to 0.7 for the oils
(Table 3), indicating that there is improved precision with
homogeneous materials where the cannabinoids are not
bound to the plant material. The minor cannabinoid
concentrations in the oils were below the quantitation and
detection limits; therefore only data pertaining to the
major cannabinoids was obtained.
Recovery The cannabinoid recovery was evaluated for the
following four major cannabinoids: CBDA, THCA, CBD,
and THC. Three concentration levels were evaluated to
represent a high, medium, and low concentration material with
stinging nettle as the matrix blank. Recoveries are summarized
in Table 4 and are within the acceptable ranges as specified by
AOAC guidelines .
Limits of detection and quantitation The method detection
limit (MDL) and limit of quantitation (LOQ) were determined
using the EPA’s method detection limit procedure . A test
sample extract was diluted to very low concentrations to
account for issues with closely eluting compounds, which will
make detection more difficult for cannabinoids with closely
eluting compounds. The detection and quantitation limits for
each cannabinoid are summarized in Table 5. The limits for
CBD are much higher in comparison with the other
cannabinoids because of the number of close eluting peaks in the
chromatogram. Most other cannabinoids have sufficient
resolution from other unknown peaks which do not impact their
quantitation and detection.
With the rapid expansion of labs analyzing Cannabis, it is
essential to have robust, versatile analytical methods. The
currently available methods have several limitations. For
example, the resolution of the minor cannabinoids in some cases
has been achieved only by selecting a less sensitive UV
wavelength to achieve baseline, while this reduction in sensitivity
would impact the quantitation of low level compounds found
in many products . Some methods fail to provide sufficient
method development information to explain extraction
solvent selection, extraction times, potential losses, degradation,
or inefficiencies [9, 14, 15]. Many methods use chlorinated
solvents with potential negative health and environmental
impacts. Other methods use high pH mobile phases pH >5.0
which is above the pKa of the cannabinolic acids . We
found that this elution system caused the peaks to tail
significantly and early eluting peaks were asymmetrical.
The demand for cost-efficient quantitative methods for
cannabinoids is growing. Many laboratories engaged in this work
lack the expertise for advanced analytical instrumentation,
such as mass spectrometric detectors. In this case, these
detectors would impose a significant cost increase in infrastructure
and expertise. Mass spectrometry (MS) would allow for
improved detection limits, selectivity, and sensitivity, but given
the performance of this method with UV absorbance detection
and the high concentrations of the major cannabinoids, the use
of MS detection does not improve the method fitness. Care
was taken to ensure that the mobile phases used for this
method are mass spectrometry compatible for those who with the
instrument capabilities require improved sensitivity and
putative identification of additional minor cannabinoids.
Our method is a significant improvement over previous
methods that can be used in a variety of settings and has
the potential to be expanded for inclusion of new
cannabinoids as required. To date, many jurisdictions only
require the quantity of total THC and total CBD in the
products [25, 26], while with improvements in analytical
instrumentation, columns, and detection techniques, the
ability to expand the regulations to acids, neutral forms,
and minor cannabinoids is straightforward. There is a
significant amount of concern around the use of GC for
quantitation of cannabinoids using in-injector
decarboxylation because of conversion issues, which can reduce the
accuracy and precision . This issue is no longer a
concern when quantifying cannabinolic acids separately
from neutral cannabinoids. The information on acid
content is also important for those that do not smoke
Cannabis as the pharmacology of acids varies compared
to neutral cannabinoids . Understanding the
cannabinoid profiles of different Cannabis strains will allow
additional information for clinical researchers to understand
the complex composition of these plants and their roles in
pain regulation and treatment of a variety of other
We developed an optimized HPLC-DAD method with
reduced extraction time and greener solvents for adoption into
cannabis testing laboratories. Sample turnaround is
significantly reduced, while method validation confirmed that the
method produces repeatable, accurate results. The sample
preparation eliminates the use of chloroform, which has been
routinely used in cannabinoid analysis, reducing material
costs, use of greener solvents, and improved laboratory safety
for personnel. This method can be used in a variety of settings
from clinical studies, research, quality control, and regulatory
evaluation of this growing industry.
Acknowledgements We would like to acknowledge partial financial
support from Northern Vine Canada Ltd (Langley, BC) in the
development and validation of an analytical method suitable for the intended
purpose of conducting routine analysis. This research was undertaken,
in part, thanks to funding from the Canada Research Chairs program.
Compliance with ethical standards
Conflict of interest the authors declare that they have no conflict of
Ethical approval this article does not contain any studies with human
or animals subjects.
Informed consent not applicable.
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