A look inside a licensed cannabis testing lab

Potency, purity, and pathogens — oh my!

In 2015, Justin Trudeau’s election campaign brought cannabis legalization into the forefront of mainstream discussion. In the wake of that campaign, a proliferation of cannabis producers and distributors sprang up and into view across Canada, bringing with them an old concern on a new, national-market scale: safety.

As burgeoning legal and grey-area markets emerged, the need was created for a new, adjacent industry to provide the analysis and safety assurance normally required of traditional food and drugs. Labs began offering testing services through which growers and cannabis users can turn a small sample into a wealth of information, and Lift News was recently granted a tour of one such testing lab.

Half an hour outside of British Columbia’s capital city, the team at M B Laboratories toils amidst an array of vials, data sheets, and state of the art, high-tech machines. They’re working with samples of cannabis in various forms to determine the potency and safety of the samples brought to them by growers, licensed producers, and their customers.

On average, M B Laboratories (MBL) receives between 10 and 70 samples each week, which they test for cannabinoid levels and terpene profiles, as well as contaminants like mould, microscopic bugs, and heavy metals. Each sample goes through rigorous processing and analysis, with results typically being available five to ten days after samples are provided.

The full testing process consists of five stages of processing; preparation, chromatography, general spectrometry, heavy metal spectrometry, and finally, microbial analysis.

Preparation (The turn-it-into-goo station)

The lab receives samples in a wide variety of forms, but most of their equipment requires samples to be entered in uniform liquid solutions. As an example of how they accomplish this, a tray was shown, holding vials containing partially dissolved gummi candies, fully ground cookies, and a green liquid that was previously a solid bud.

Vials of solution waiting to be tested

Each sample is first pulverized completely, so as to ensure uniform homogeneity (for exapmple, a dried flower would be turned into a fine powder and mixed thoroughly, so that every test run from that bud would be made up of an equal representation of the overall composition). Then sub-samples are taken and introduced into solvent, and eventually rendered into a pure liquid form that can be analyzed by the lab’s highly sensitive instruments.

MBL accepts samples from any person with a doctor’s prescription or proof of a valid medical condition, as well as any person or company with a license under the current ACMPR or former MMAR and MMPR regulations. Operating under a general narcotics license, they’re one of just over a dozen labs in Canada that are legally sanctioned to perform testing and analysis of cannabis, and that adhere to international USP standards.

Most commonly, the samples they receive are in the form of oils, edibles, and dried flowers, however sometimes people also bring them samples of individual components such as trichomes and roots. One of the first samples shown on this tour was a live plant—still potted in soil—which the client had requested be screened for unwanted fungal growth and nutrient deficiency, aiming to improve the health of their suffering crop.

Once samples are prepared in solution, they’re ready to be moved on to analysis.

Chromatography (The potency-and-pesticides station)

The first testing station on the tour was an area that serves two primary functions: the measurement of cannabinoid levels to determine potency, and the inspection of samples to detect the presence of pesticides.

The station consists of two machines, each one an Ultra High Performance Liquid Chromatograph (UHPLC)—extremely sensitive devices that measure the amounts of individual components that make up whatever is being tested. In broad terms, they do this by passing the sample through a structure that causes the components to separate, so each component can be assessed and compared to official standards and control samples such as pure THC, CBD, etc.

The first chromatograph in which samples are tested at MBL is a Tunable UV Detector (TUVD), which uses ultraviolet light to measure the absorbance of various cannabinoids. That absorbance measurement is then used to determine the potency of the sample, and to help map the overall cannabinoid profile of the strain. The second machine is a Liquid Chromatograph with dual Mass Spectrometers (LC-MSMS), which M B Labs uses to detect pesticides and fungal toxins.

In a nutshell, one machine is used to measure the things clients want, and one machine is used to detect things clients don’t want.

chromatograph machine

But the combination of the two machines is greater than the sum of their parts. The TUVD, which measures on a scale of parts-per-million, detects and identifies various cannabinoids. Meanwhile the more sensitive LC-MSMS, which measures on a scale of parts-per-billion and even parts-per-trillion, provides confirmation of the initial TUVD results, and vice-versa for the detection and confirmation of pesticides. This combined result set provides more confidence in the individual results either machine produces, as well as a more comprehensive view of the overall composition of the strain or sample being tested.

But just as there are more things in this world than are dreamt of in our philosophies, so too are there more things in cannabis than simple potency and contaminants. For a closer look, samples are brought to the next section of the tour...

Mass Spectrometry (The terpenes-and-more station)

Most people are familiar with cannabis, most boomers with hashish, and even your great grandmother has probably heard the term ‘THC’ once or twice. But a rapidly growing niche among connoisseurs centers around a group of molecules called terpenes, which are found in various combinations within virtually every food and flower known to humankind. These terpene molecules are responsible for the flavours and smells in cannabis, and their medicinal qualities are the subject of much recent research.

The mass spectrometry station at MBL provides details about terpene composition, as well as in-depth analysis of any pesticides detected during the chromatography stage. Their spectrometers ionize samples by bombarding them with electrons, and then separate the ions based on their mass-to-charge ratio. Once sorted by polarity and mass, the output is then processed by an advanced piece of software that matches detected compounds to entries in a database of pesticides, as well as to MBL’s own internal library of terpenes.

Mass spectrometers

Samples are screened for over 900 different compounds, which include 37 identified terpenes—especially important in live resin or non-decarboxylated extractions.

MBL is also developing a technique that uses metabolic and terpene profiles to help producers and end users identify strains and traits that are best suited for various conditions and preferences. The new technique, which MBL has already used to build a database of 150 distinct terpenes, is due to be presented at the upcoming Lift Expo in Toronto this Spring.

Before leaving the general spectrometry station, part of the evaluation can include testing for residue from solvents used during extraction for concentrates and edibles.

Once this round of spectrometry is complete, samples move on to be tested for heavy metals.

Heavy Metal Mass Spectrometry (The brutal-inferno station)

At the center of the heavy metal station burns a white-hot flame, surrounded by a black mesh cage. MuchMusic hasn’t started playing music videos by 3 Inches of Blood again, it’s just science at work.

Standing by the spectrometer was MBL’s senior analytical chemist, Dr. Harry Hartmann. His outward appearance matching that of the quintessential bespectacled scientist, Dr. Hartmann provided a detailed walkthrough of how heavy metals like lead, chromium, and mercury are detected within cannabis samples, and how amounts of metals are measured.

This machine, an Inductively Coupled Plasma Mass Spectrometer (ICPMS), individually tests and measures amounts of 33 individual metals. According to Dr. Hartmann, the metalloids he finds in cannabis most commonly are arsenic and cadmium (in small amounts). He says the number one cause of positive hits is phosphorous fertilizer, which is often very high in cadmium.

“Lots of metals occur naturally in soil, fertiliser, etc,” he volunteers. “This tests to ensure that if any are found, the amount is within safe levels.”

Samples entered into the ICPMS undergo a process whereby they are subjected to a white-hot flame that burns hotter than a welding torch. The machine applies radio waves to an internal coil within an argon chamber, until it causes the argon to burn. Dr. Hartmann adds, “argon doesn’t burn easily, you’ve really gotta sock it to it”.

A vacuum then sucks the gas into another chamber. “You basically just vaporise it,” says Hartmann. “You strip off the electrons, and are left with plasma.” The plasma is then sent into a spectrometer which measures the individual masses within the plasma.

To prevent light particles (photons) from affecting the results, the path the gas takes on its way to the mass spectrometer zig-zags back and forth. This causes the light to be stopped at the angled walls, while the metals being measured pass through to the end of the corridor, into the detector.

The particular model of ICPMS used by MB Labs incorporates a newer feature that further breaks up compounds on their way to the spectrometer. This is especially useful when testing for mercury, which Dr. Hartmann says has traditionally caused problems in older industry machines, often resulting in false positives. The newer model used by MBL fixes that problem by bombarding the samples with hydrogen-helium gas as they pass through the machine.

When samples are finished making their way through chromatography and spectrometry, they’re sent upstairs to the microbiology lab.

Microbial Analysis (The omg-what’s-that station)

The final stop on the tour, this lab had no big appliances or machines with flaming jets in them. Instead, the microbiology lab had two high-powered microscopes, and enough petri dishes to build a small fort.

Microscope in the microbial analysis station

The two primary categories of things tested for in this stage are foreign matter (eg, "spider bits," pieces of glass, or anything else that wouldn't normally be found within a plant's biology), and foreign organisms (ie, things that are actively growing, such as bacterial culture, mould, or other fungal growth).

That second category also includes pathogens. Most commonly, producers of edibles bring M B Labs samples to test for salmonella before being sold in dispensaries, but according to MBL, salmonella is quite uncommon compared to shigella, which they say is detected more often.

Shigella is the bacteria responsible for causing shigellosis, a diseases that behaves similarly to (and is often mistaken for) salmonella. A subspecies of shigella, ‘Shigella dysenteriae’ (aka dysentery) was responsible for the deaths of over 80,000 soldiers during the American Civil War. With modern sewage treatment standards shigella is uncommon in developed nations, but according to Dr. Hartmann, the biggest cause of this kind of bacteria being found in cannabis is that some cottage-industry producers use untreated sewage and/or 'manure tea' as fertilizer.

"They think it's organic," says Dr. Hartmann, "but in fact, in terms of food testing and drug testing, organics are the worst. Growers think it's all-natural, but natural and clean are not necessarily the same." He adds, "there's a very good reason things go one-way," gesturing in mimicry of digestive peristalsis.

MBL’s general manager, Victoria Ingram, expanded on that, adding that the majority of edibles producers bring them samples with the simple goal of verifying potency. "What we're trying to promote right now," she says, "is that it's also a food product, and so it needs to follow the same safety guidelines that any other food product has to follow, including a full microbiological screen."

Testing is performed by taking culture samples and putting them in petri dishes coated in a film that contains inhibitors. The inhibitors prevent certain cultures from growing, while allowing others to grow unfettered. Under the microscope, their analysts are able to detect, identify, and even count individual spores.

With the tour coming to an end I had a few more questions, not least of which was who their typical customers are. According to Ingram, most of their samples are brought to them by growers, however they’re increasingly seeing samples from end users who bought something from a licensed producer or a dispensary and had a bad reaction to it.

As an example, although licensed producers are prohibited from using unauthorized pesticides, recently two Canadian LPs issued recalls after the pesticides myclobutanil and/or bifenazate were detected in their products.

Another example Ingram offered was a sample provided by an end user who found that the effects from a dispensary or LP purchase weren’t as expected. When tested, the dosage of the sample was found to be three times larger than what was labelled on the packaging.

Gummy bears being dissolved in preparation for testing

Ingram continued. "People are using it as a medicine," she said, adding, "we want to make sure they're consistently getting what they think they're getting, and that they're not getting anything they shouldn't be."

She also emphasized that accessibility of information is a priority for MBL. "We pride ourselves on being available. Even just for someone to be able to phone us up and ask if we test for something—and why it's important—is a big component."

MB Labs will be celebrating its 35-year anniversary next year. When they first started offering cannabis testing roughly three years ago there were only two other officially licensed cannabis testing labs in Canada, both east of the prairies. Now there are 17, with at least one in almost every province.

Those labs will be increasingly important as the federal government’s plan for legalization approaches implementation, with producers of cannabis, concentrates, and edibles facing the inevitability of the cannabis industry being subject to the same regulatory standards as existing food and drug markets.


In this article

Join the Conversation