Hydrolife Magazine December/January 2017 (USA Edition)

grow
TECHNIQUE PROS CONS
Colorimetric
Inexpensive, rapid, can be done by a grower
Only able to show presence of
THC or CBD over a threshold
Thin Layer
Chromatography
(TLC)
Inexpensive, rapid
Semi-quantitative method (the
compound is present or absent
over a certain concentration)
Enzyme-linked
Immunosorbant Assay
(ELISA)
Simple, can be sensitive (able to correctly detect
the presence of the compound of interest)
Only able to detect THC and
CBD, cross reactivity with other
compounds known to occur
Gas Chromatograph
(GC)
Excellent for measuring small concentrations,
sensitive, specific (able to differentiate between
the compound of interest and compounds that
may interfere with the test), accurate (measuring
closely to the true value)
Unable to easily differentiate
between carboxylated
and decarboxylated
compounds, measures total
of each cannabinoid
High Performance
Liquid Chromatography
(HPLC)
Highly sensitive, very specific, accurate and
precise (two or more measures agree), able
to differentiate between carboxylated and
decarboxylated compounds
Less efficient than GC,
time-consuming
Table 2: Comparison of Analytical Methods for Cannabinoid Potency
product has been sitting around
for a long time. Same goes for low
levels of acid-form cannabinoids.
Carboxylation is the presence of
a carboxylic acid molecule on a
cannabinoid. Heat, light, or alkaline
conditions can remove this molecule
in a process called decarboxylation,
which creates the active, neutral
form of the cannabinoid. So, as plant
material ages, its levels of acid-form
cannabinoids begin to decrease.
Quantitation of
Total Cannabinoids
A lab test can also report a total
value of the cannabinoids. This
is a calculation of what neutral
forms of the cannabinoids would be
present if there was a completely
efficient decarboxylation process.
A conversion factor is used to
calculate this value.
For example, the levels of THC
and THCA would be converted
to a total measure of THC. If
a sample had 10 per cent
THCA, the total value of
THC would be calculated
to 8.77 per cent.
Available Testing Methods
There are a variety of rapid and highly
sensitive methods for analyzing a
product’s cannabinoid profile. The most
common tests available are outlined in
Table 2, which also looks at the benefits
and drawbacks of each method.
As you may have guessed, thinking
about the exciting and changing world
of cannabis testing is my kind of fun.
It can turn gut feelings into hard facts,
which also makes it an extremely useful
tool for a grower. Cannabinoid testing
can confirm what you know about your
growing skills while showing you a
world of other medically important
cannabinoids that you have access
to in your own garden.
Jodi McDonald is the president and
founder of Keystone Labs and is a medical
microbiologist, inventor, and super
science-geek. She has 20 years’ experience
in the quality control, regulatory, and
quality assurance environment for the
pharmaceutical industry. Jodi believes
testing is essential for taking control of
your personal health.
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grow. heal. live. enjoy.
myhydrolife.com