Did you know that over 500 different chemical components have been reportedly found in cannabis? Approximately 100 of those are cannabinoids, the main bioactive components of cannabis and hemp. The remainders are terpenes and other products like carboxylic acids.
So how do scientists tell these compounds apart? They use a scientific method called chromatography.
What is chromatography?
The word “chromatography” actually comes from words meaning “color writing.” Chromatography is one of the most important techniques a chemist can have, using it to separate out mixtures into their individual components.
Chromatography is widely used by chemists in every industry. It helps at crime scenes, and it helps to identify biological materials. In the cannabis industry, it is used to identify the components of the extraction from hemp or cannabis. It is also used as a testing mechanism on end-products such as CBD oils or cannabis flowers.
In chromatography, a mobile phase (in this case, the cannabis product being tested) moves over a stationary phase of a liquid or solid substance. As the mobile phase moves, it separates out into its separate components onto the stationary phase.
Think of it as a swim meet. Swimmers (mobile cannabis substances) line up on the starting block to move across water (the stationary phase). Swimmers are slower or faster depending on their innate qualities, meaning the individual substances move at different speeds across the stationary solid material.
One of the biggest issues in the cannabis industry today is the testing of products marketed to consumers. Because the products are not regulated by the U.S. Food and Drug Administration (FDA), there are issues in the industry.
Certainly, states that have legalized cannabis are implementing and enforcing testing. For example, in Michigan, the state recalled cannabis strains that tested positive for arsenic and cadmium, a heavy metal. Other news reports talk about cannabis products testing positive for toxins and pesticides.
While states should perform testing, growers and producers have a responsibility to test their products before they ever reach the state lab. This is something that we take very seriously at PhytoFamily.
Chromatography at PhytoFamily
We use a technology called chromatography, a very popular technique for testing the safety of cannabis. Chromatography has become an extremely important technology for the industry, as producers deal with the many new state regulations. One of the most important tests is the determination of the potency of the cannabinoid in the product, to ensure the customer gets what they are paying for and also to ensure that the formulation does not exceed certain state-stipulated thresholds, like for THC.
Chromatography is used for much more than just testing, though. The technology is used to separate compounds during the cannabis extraction process. In this way, PhytoFamily can create custom-tailored cannabinoid extracts. Chromatography allows us to separate out and select specific cannabinoids to concentrate them higher than levels found in any cannabis flower.
Many of these regulations require growers to test their plants for any signs of pesticide, solvent, and heavy metal contamination. Testing the intensity of cannabinoid potency is also a serious step required by regulations.
There are a number of different chromatography methods used in the cannabis and hemp industries. Let’s take a look.
High-Performance Liquid Chromatography (HPLC)
High-performance liquid chromatography (HPLC) is widely used in the cannabis industry. It is more accurate than other methods and therefore is the preferred method of separating cannabinoids and also the preferred method used for testing.
HPLC is a form of column chromatography, meaning the stationary phase is a vertical column filled with highly absorbent silica. The cannabis substance is pushed into the column at high pressure to split into its individual components. The column is then removed, and the components are analyzed. The main reason most cannabis outlets choose HPLC is that this method requires no heating. HPLC is more sensitive, more precise and much faster than other methods.
Thin Layer Chromatography (TLC)
Like HPLC, thin layer chromatography (TLC) is another form of liquid column chromatography. The mixture being studied is placed at one end of the column, and another substance called an eluant (eluent) is poured in to help move the mobile phase along.
Gas Chromatography (GC)
Gas chromatography is particularly used to screen samples for residual solvents; the method is very accurate at detecting volatile compounds.
This method is sometimes referred to as either vapor-phase chromatography (VPC) or gas-liquid partition chromatography (GLPC), and uses gases as the mobile phase, and it is a highly automated analysis performed with lab equipment called a gas chromatograph.
A tiny sample of the mixture is injected into the chromatograph, then the mixture is heated to instantly vaporize it. The eluant is added as the carrier; in gas chromatography, neutral gases like hydrogen and helium are typically used. The eluant helps the vaporized mixture move through the column to separate out into its components.
Supercritical Fluid Chromatography (SFC)
Supercritical fluid chromatography (SFC) is a form of gas chromatography that uses carbon dioxide as the mobile phase. The principles of this method are very similar to HPLC, and the same silica columns are used. However, because gas is used, the entire system is pressurized so that the liquid and gas properties converge (which is why it is sometimes called convergence chromatography). The method is commonly used as a purification method in the pharmaceutical industry.
Centrifugal Partition Chromatography (CPC)
Centrifugal partition chromatography (CPC) is also used for cannabis and hemp extraction and purification. CPC is similar to HPLC, but it uses a liquid rather than a solid for the stationary phase. The method is newer and not yet widely used in commercial operations. Instead, it is typically used by researchers. However, the method is much less expensive and therefore has been growing in popularity for commercial use. HPLC takes much less time – around 30 minutes — and the other methods use silica, but CPC does not. The CPC columns are also reusable, and all of these efficiencies make the method more cost effective. The end result of CPC is a much purer compound – some extracts reach nearly 100 percent purity levels.
Chromatography is not exclusive to the cannabis industry. These methods are used by chemists across the world, but there are a growing number of specialized cannabis chromatographs being developed; one example is an HPLC chromatograph device called Shimadzu’s Cannabis Analyzer for Potency.
The cannabis industry is in its infancy. In the future, look for customized devices specific to the cannabis industry. These instruments will allow different analysis methods, and will be highly sensitive to allow testing for terpene levels, solvent levels and total potency.