Testing Tools for Estimating Cannabis Potency

The cannabis industry is poised for growth as legalization spreads and consumption increases. The increase in cannabis medical research and the implementation of cannabis testing and labelling regulations will drive the adoption and growth of cannabis testing tools, including specialized potency analyzers.

Several technologies are used for testing cannabis potency, but no government agency certifies specific makes and models.

These are designed for laboratory use. They are labor intensive, time-consuming, may only measure one parameter at a time, can require the use of expensive solvents and reagents, and are often ill-suited for real-time process measurements and most important, sample destructive.

Thin Layer Chromatography (TLC)

Thin layer chromatography systems are used to qualitatively separate the components of non-volatile samples. TLC systems consists of either a glass, plastic, or metal plate, coated with a thin layer of adsorbent material, such as silica gel, aluminum oxide, or cellulose, which acts as the stationary phase.

A sample or mixture (i.e., the mobile phase) is applied to the near the edge of the plate and is drawn up via capillary action. Individual analytes of the sample are separated by traveling at different rates and to different extents on plate. TLC is an inexpensive, fast, and easy chromatography

method and it usually serves as a pre-screening option for HPLC.

TLC is an inexpensive and fast screening method for the positive identification of cannabis. It can be used to distinguish Δ9-THC dominant strains from CBD dominant strains and fiber types.

LC methods are generally the most widely accepted method for determining cannabinoid concentration given that that it allows for the individual quantitation of free (neutral) and acidic cannabinoids prior to decarboxylation.

Liquid Chromatography (LC): HPLC / UHPLC

High performance (HPLC) and ultra-high performance (UHPLC) liquid chromatography systems are used to separate the components of complex liquid samples prior to analysis.

Gas chromatography systems are used for separating a vaporized sample into its principal components for further analysis. Using a GC, heat is applied as part of the testing process and cannabinoids such as THCA or CBDA can change form, depending on the level of heat applied.

 

CBDA and THCA change form at temperatures as low as 40-50C (104-122F). A GC heats the sample up to anywhere between 150-200C (302-392F) for its processes.

 

Therefore, GC is suitable for quantifying total cannabinoid content. An HPLC, however, is preferred over GC because it does not apply heat in the testing process and cannabinoids can then be measured in their naturally occurring forms.

Gas Chromatography (GC):

Mass Spectrometry (MS):

A mass spectrometer is a sophisticated analytical instrument used to identify and quantify the individual components in complex mixtures of solids, liquids, and gases.

MS is powerful for the analysis of not only cannabinoids but also contaminants and pesticides.

Near Infrared Spectroscopy (NIRS) for In-House / Field Testing of Cannabis Potency

A spectroscopic form of testing

NIRS uses the light spectrum to assess the chemical contents of the test subject. By beaming wavelengths of light onto an object and detecting the wavelength intensities that bounce back, spectrometers estimate the chemical contents of a test specimen without altering it. NIRS is appropriate for many applications and approved by the U.S. Food and Drug Administration for medical procedures, pharmaceutical testing, and food testing.

Fast testing

NIRS is fast, requires no sample preparation, and can analyse multiple parameters with a single measurement. The technology addresses the major requirements for a suitable analytical method that is rapid, suitable for high-throughput analysis, on-site capability, chemical specificity, minimal and non-destructive sample preparation, and no special skillset is required to operate. NIRS is perfect for testing high-dollar crops since it is non-destructive.

Accuracy

Though spectral examination methods like near-infrared spectrometry are unlikely to match the accuracy of a single HPLC test, the ability to quickly run multiple tests, and average results, better addresses the high potency variance common to cannabis.

This includes food and agriculture, pharmaceutical and dietary supplements, polymers, oil, and gas.

Major providers of NIRS equipment for a wide range of analytical applications are: Thermo Fisher Scientific, Bruker, Unity Scientific, FOSS, Buchi, ABB, PerkinElmer, Agilent Technologies, Yokogawa, Shimadzu, Guided Wave (Advanced Group), Zeutec, and Hitachi.

GemmaCert specializes in cannabis potency testing solutions based on NIRS.

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Important things to remember

No two cannabis flowers are the same.