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Potency Testing by LC-MS, the Future of Cannabinoid Testing?

By
  • Jamie York
Tags
  • #Cannabinoids
  • #Product Selection
  • #Raptor LC Columns
  • #Restek Reference Standards
  • #Method Development
  • #Method Optimization
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  • #HPLC & UHPLC Columns
  • #Analytical Columns
  • #Guard Columns
  • #Reference Standards
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  • #Botanicals
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  • #Botanicals
  • #Cannabis
  • #LC
  • #MS
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Potency testing is the bread and butter of the cannabis industry. This analysis is typically performed by LC-UV as this instrumentation is relatively inexpensive and requires minimal training. There are over 150 cannabinoids that have been discovered thus far, with more likely to be discovered in the coming years as cannabis research continues to accelerate. While LC-UV is a robust and reliable approach, it has some limitations. LC-UV is hindered by the need to resolve all analytes and lacks sensitivity when compared to MS. As new cannabinoids are discovered and gain interest, additional cannabinoids will need to be added into potency testing methods. MS can offer a sensitive and selective analytical solution which enables lower limits of detection and eliminates the need to resolve compounds that are not isobars. Here, a method has been developed for the analysis of 21 cannabinoids by LC-MS in 9 minutes that also achieves the resolution of all isobaric compounds.

Column

Raptor ARC-18 (cat.#9314A62)

Dimensions:

150 mm x 2.1 mm ID

Particle Size:

2.7 µm

Guard Column:

Raptor ARC-18 EXP guard column cartridge 2.7 µm (cat.#9314A0252)

Temp.:

30 °C

Conc.:

500 ppb

Inj. Vol.:

2 µL

Mobile Phase

 

A:

Water, 0.1% formic acid

B:

Acetonitrile & Methanol 50/50, 0.1% formic acid

Time (min)

Flow (mL/min)

%B

0

0.5

80

0.9

0.5

80

Ion Mode

ESI (+)/(-)

Detector

MS

 

Peaks

SIM

Ion Mode

Cannabidivarin

287

+

Cannabidivarinic Acid

331

+

Cannabidiol

315

+

Cannabigerol

317

+

Cannabidiolic Acid

357

-

Tetrahydrocannabivarin

287

+

Cannabigerolic Acid

359

-

Cannabichromevarin

287

+

Cannabinol

311

+

Cannabidiphorol

343.5

+

Tetrahydrocannabivarinic Acid

331

+

Δ9-Tetrahydrocannabinol

315

+

Δ8-Tetrahydrocannabinol

315

+

Cannabinolic Acid

353

-

Cannabicyclol

315

+

Cannabichromene

315

+

Tetrahydrocannabinolic Acid-A

357

-

Cannabicitran

315

+

Tetrahydrocannabiphorol

343.5

+

Cannabichromenic Acid

357

-

Cannabicyclolic acid

357

-

In the above compound table, each analyte is listed with their SIM and ESI ion mode. All isobars are color coded and these compounds will need to be chromatographically separated.

blog-potency-testing-by-lc-ms-the-future-01.png

In this method, 21 cannabinoids are capable of being analyzed by LC-MS. By using MS detection, some of the burden is lifted to chromatographically separate all compounds, as only isobars need to be separated. Some of the isobars are more difficult to separate than others. The most challenging set to separate are the m/z of 315, which consists of THC and its isobars.

blog-potency-testing-by-lc-ms-the-future-02.png

By using this method, the desired resolution can be achieved for key compounds, including THC isobars. Additional cannabinoids can be added to the analyte list as more are discovered with minimal further optimization. Could MS be the future of cannabinoid potency testing?