Maximum Yield Cannabis USA December 2017 / January 2018 | Page 48

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Some examples of the solvents are included
in the table below (Table 2: Solvent Examples).
Class 3 solvents are less toxic and have lower
risk to human health. There are no long-term
toxicity or carcinogenicity studies for many of
the Class 3 solvents.
Health Canada does not specify a method that
must be used for the extraction of cannabis oil.
Producers can choose from a number of processes
for extraction, including those that use carbon
dioxide or water and those that are solvent-less.
These three have less potential for toxicity, but
there are still concerns about the presence of
residual solvents as solvents used to clean the
equipment can find their way into the end product.
In Canada, the federal government is concerned
about the health and safety of patients and have
specified limits for residual solvents. Health
Canada has mandated a requirement for residual
solvent testing of all oil extracts.
In the lab, we use a robust method of analysing
residual solvents called headspace sampling
with a gas chromatograph. In a headspace
analysis, the sample is heated in a gas-tight
vial to vaporize the volatile components. An
automated syringe obtains a small sample of
the gases in the headspace of a sealed vial from
the sample preparation. The sample includes
vapors of all volatile components in the vial. The
sample is injected into a gas chromatograph for
separation and detection of residual solvents.
“
Health Canada has mandated a
requirement for residual solvent
testing of all oil extracts.”
This is an extremely sensitive test for most of
the relevant volatile compounds. Residual
solvent amounts are commonly expressed in
parts per million (ppm).
With a good-quality test lab conducting the
right testing, all adulterated material can be
identified and destroyed to protect the end-user.
I think about the gentleman that I met at the expo a
lot. He was going to send me the remains of the oil
that he had, in order for us to test it for the presence
of residual solvents. I never heard back from him,
and often wonder how he is making out. I hope he
found the answers he needed to improve his health
and begin to feel better.
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.
TABLE 2: SOLVENTS EXAMPLES
SOLVENT
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CLASS
HEALTH / SAFETY CONCERN
Benzene 1 Carcinogen
Carbon Tetrachloride 1 Toxic, environmental hazard
1,2-Dichloroethane 1 Toxic
1,2-Dichloroethane 1 Toxic
1,1,1-Tricholorethane 1 Environmental hazard
Acetonitrile 2 Central nervous system: headaches, numbness, tremors
Chlorobenzene 2 Central nervous system: headaches, numbness, tremors
Chloroform 2 Probable carcinogen
Hexane 2 Central nervous system effects: numbnes