Methods for Testing Cannabis Potency: Understanding HPLC, GC-MS, and LC-MS

Cannabis potency testing is crucial for determining the levels of cannabinoids, such as THC and CBD, in cannabis products. Accurate potency testing helps consumers make informed decisions about the potency and effects of different cannabis products. In this blog, we will dive deep into the different methods used to test cannabis potency, including HPLC, GC-MS, and LC-MS. We will explain the differences between the methods, their strengths and weaknesses, and which one is best suited for different scenarios.

HPLC:

High-performance liquid chromatography (HPLC) is a widely used method for cannabis potency testing. It involves the separation of cannabinoids in a sample using a liquid mobile phase and a stationary phase. HPLC is known for its high sensitivity, accuracy, and reproducibility, making it a preferred method for potency testing. HPLC seems to me to be the litmus test for whether a laboratory is functioning well. If you can find a set up, you can enter the parameters into your system, and, can make the system behave and you can interpret the results that it spits out, you can probably do the same for every other piece of equipment in the lab with a little elbow grease.

GC-MS:

Gas chromatography-mass spectrometry (GC-MS) is another popular method for cannabis potency testing. It involves the separation of cannabinoids using a gas mobile phase and a stationary phase. GC-MS is known for its high sensitivity and specificity, allowing for the detection and quantification of trace amounts of cannabinoids. You can also use a GC-FID for residual solvent testing. In my experience, the GCMS is best used for terpene testing. When it works, it works, and you can put sample in and get results without much fuss, but getting it to work in the first place is the trick. As it stands, typically terpene testing is not required, but if you want to learn more about the evolution of testing requirements, we have a blog post about it.

LC-MS:

Liquid chromatography-mass spectrometry (LC-MS) is a newer method for cannabis potency testing that combines the separation capabilities of HPLC with the detection capabilities of mass spectrometry. LC-MS offers high sensitivity and specificity, making it suitable for the detection and quantification of cannabinoids in complex matrices. However, LC-MS also requires a complex setup and expensive equipment, which can be frustrating as pesticide analysis should, in my opinion, continue to be standard for cannabis testing. That being said, we have yet to come across an (functioning, we don’t fix broken instruments) LCMS system that we couldn’t get to work. Ask us about your LCMS problems because I have a theory that most laboratories have some.

Choosing the Right Method:

The choice of method for cannabis potency testing depends on various factors, including the desired level of accuracy, sensitivity, and specificity, as well as the available resources and expertise. HPLC is a preferred method for high-throughput cannabis potency testing due to its high sensitivity and reproducibility. GC-FID is suitable for the detection of residual solvents. LC-MS is a newer method that offers high sensitivity and specificity which is best suited for pesticides in my experience. These are often the big 3 and sometimes heavy metals is included with its own set of challenges as well. pH and water activity can need little in the way of method development as the instrument is simple out of the box.

In conclusion, cannabis potency testing is crucial for ensuring accurate labeling and informed consumption of cannabis products. HPLC, GC-MS, and LC-MS are popular methods for cannabis potency testing, each with its strengths and weaknesses. Choosing the right method depends on various factors, including accuracy, sensitivity, specificity, and available resources. At our cannabis consulting firm, we offer expert guidance and support for cannabis potency testing, helping businesses meet regulatory requirements and ensure the quality and safety of their cannabis products.

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