Houdini Lab

Chemical Solvents Used in the Extraction of Cannabis

Cannabis extracts are becoming a more prominent sector of the legal cannabis market in the United States. Cannabis extracts are used in a variety of applications, ranging from industrial extractions for supply to the cannabis industry’s food and beverage sector to mass-produced vape cartridges to artisanal cannabis concentrates for the retail consumer. Cannabis extracts deliver the pure essence of the flower in a more concentrated format.

It is widespread practice in both commercial and black market cannabis manufacturing to extract cannabis using solvents. In order to ensure that the items are safe for eating, certain steps must be performed. Examine the various solvents, including their advantages, disadvantages, and dangers as they relate to the various applications.



Residual solvents have been linked to a variety of health problems. As a result, several states have adopted the criteria established by the United States Pharmacopeial Convention and the Food and Drug Administration in order to eliminate this risk. These guidelines classify a total of 59 extraction solvents into three categories, which are listed in this order: those that should be avoided at all costs, those that must adhere to severe requirements, and those whose use is restricted merely by GMP and other quality-based norms.


Initially, butane and propane were not included in the early USP and FDA-guidelines, despite the fact that they were already effective extraction solvents. However, the amended FDA-guidelines for 2019 designated butane and propane as “Generally Recognized as Safe” (GRAS) in the category of Class 3 solvents, whereas previously they were not.



When it comes to cannabis extraction, solvent-based extraction is a favorite of the business, especially when it comes to manufacturing extracts for use in food, pharmaceuticals, and personal care products. There are now four types of this approach that are known to exist.


The following types of solvents are favoured above others because of their effectiveness, efficiency, and FDA approval for each application. The following are some of these solvents, some of which contain substances that were previously used:


Extraction of Hydrocarbons


Because of their tremendous potential, hydrocarbons are extremely valuable in the cannabis extraction sector. There were more hydrocarbons used for extraction in the past, but because of their high toxicity and flammability, the majority of them were banned. Hexane, methyl ethyl ketone, acetone, and ethyl ether are just a handful of the hydrocarbons that fall into this category. According to the Food and Drug Administration, butane and propane are the most suitable hydrocarbons for cannabis extraction.


The Advantages of Butane and Propane


Volatility is really high.

There is little danger of toxicity.

Effectiveness and efficiency are really high.

Specificity is very high.

Alcohol Extraction is a type of extraction that uses alcohol to extract a substance.


While hydroxyl-compounds are highly successful in extraction, they are less particular in their action, having a proclivity to dissolve pigments and waxes in addition to the target extract. Nonetheless, there are two often used compounds: isopropyl alcohol and ethyl alcohol (ethanol), the latter of which is less popular due to the creation of acetone in the liver.


Other hydroxyl-compounds that were previously utilized without restriction but are now subject to severe regulations include:


Class 2 solvents such as methanol and toluene I have a high potential for producing visual nerve disorders and convulsions.


Class 3 substances such as acetone and isopropyl alcohol (ii) pose a significant risk of brain harm.


Ethanol is available in a variety of grades.


The four different grades of ethanol are as follows:


Ethanol of FCC-Quality

Ethanol of the highest quality (USP-grade)

Ethanol with a high purity level (HPLC)

GNS-Grade Ethanol is a high-quality ethanol.

This grade is also known as the American Chemical Society (ACS) grade, and the GNS-Grade is known as the GPC-grade.


The Advantages of Ethanol


Exceptional efficacy

Laboratory and health-safety precautions

Storage is simple.

It is a reasonably priced option.

Super-Critical Fluid Extraction is a type of fluid extraction that is extremely effective.


It is the process of separating target extracts from the plant’s matrix with the assistance of supercritical fluids. At the supercritical point, the temperature and pressure rise over the critical point, resulting in the fluid exhibiting the properties of both liquids (density) and gases (compression and expansion) (transferring and penetrating ability).


Many supercritical fluids have been either banned or subject to rigorous controls because to their potentially harmful effects on the environment and human health. These include nitrogen oxide, ethylene dioxide, ethane, and benzene, among other substances.


Among all forms of solvents, carbon dioxide is the most widely used and FDA-approved for extraction because of its environmental safety and excellent purity.


CO2 has a number of advantages.


It is a reasonably priced option.

Essentially chemically inert

Surface tension is low, and the critical point is safe.

Low viscosity and high diffusivity are characteristics of this material.



R134a Terpene Wash is a terpene wash containing R134a.


The COMERG team developed a novel extraction approach for R134a known as “tetrafluoroethane” extraction, which is analogous to carbon dioxide extraction. After being certified as a GRAS solvent by the Food and Drug Administration (FDA), the solvent yields full-spectrum, post-winterized extracts while also extracting terpenes, live resins, and cannabinoids.


Washing with a Dual-Solvent System


Despite the fact that R134a was the first to use this method, it is effective with carbon dioxide extraction to eliminate the need for further treatments; R134a extracts terpenes and live resins in 10-15 minutes, whereas ethanol separates cannabinoids in 30-60 minutes.


R134a has a number of advantages.


Easy to understand and use

Safe and reasonably priced

It is simple to scale up.

Effective and efficient in every way

Residual Solvents: How to Deal with Them


The fundamental purpose of most solvent-based procedures is to generate an output that is free of solvents. This, however, may not be the case due to the presence of residual solvents in the finished product, which are referred to as Residual Solvents in the industry.


The Influence of Residual Solvent


They are generally considered to be a health hazard, depending on the type and quantity of solvent present. Therefore, extraction industries conduct additional tests to check for the presence of these solvents, contaminants, and other residues in their products.


Residual Solvents are being tested for.


The Headspace Gas Chromatography/Mass Spectroscopy (GC/MS) technique is the most efficient method for determining the presence of residual solvents in extracts.


After dissolving the sample in a high-molecular-weight substance such as dimethylformamide, it is placed in a headspace vial to be tested for sensitivity. The sample is heated in a sealed vial, causing the molecules to transition from the liquid phase to the gas phase. Afterwards, technicians extract around 1mm of gas and inject it into a GC-detector, which separates the compounds based on their size and polarity.


Finally, the compounds are sent to the Mass Spectrometer, where they are qualified and quantified in terms of their solvent content.


Markets that are more advanced have more advanced processes.

The cannabis market has matured, and along with it, our understanding of the many products has grown as well. In order to ensure the safety of cannabis products for consumers today, advanced production and testing technologies are required.


As federal legalization progresses, cannabis growers may expect a greater number of testing and regulatory bodies to become engaged in the production of their goods. In the same way that some solvents were eliminated as a result of state legalization, stiffer federal limitations might alter the playing field. Quality cannabis manufacturers will be able to withstand the test of time if they place the highest priority on consumer safety.