7 minute protocol for testing 9 neutral cannabinoids on SRI 310-MM GC

Testing and Analytics
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So you’ve got In House analytics in the form of an SRI 310-MM GC and you want to test for a bunch of different things. But you’re impatient and hate waiting 14 minutes per test.

So how would you like to be able to quantify 9 cannabinoids in 7 minutes instead?

Here’s how we do it:

Sample Preparation
According to SRI standards, 100mg of sample in 40mL methanol with internal standard

GC Hardware Information
SRI 310C Gas Chromatograph
Restek MXT-502.2 5m, 0.53mm ID, 0.25um guard column followed by
Restex MXT-502.2 30m, 0.53mm ID, 0.25um column
On-column injection - [NOTE THAT COLUMN IS ON NON-STANDARD (terp/residual solvents) INJECTOR]

Restek Standard 34132
Cannabinoids Neutrals 9 Standard
1000ug/mL each in P&T Methanol:

Cannabichromene (CBC)
Cannabicyclol (CBL)
Cannabidiol (CBD)
Cannabidivarin (CBDV)
Cannabigerol (CBG)
Cannabinol (CBN)
d8-Tetrahydrocannabinol (d8-THC)
d9-Tetrahydrocannabinol (d9-THC)
Tetrahydrocannabivarin (THCV)

GC Events Program
0.000 Zero
0.000 Sound
2.000 Integration - Based
2.500 Integration - Based
3.000 Integration - Based
3.500 Integration - Based
4.000 Integration - Based
4.500 Integration - Based
5.000 Integration - Based
5.500 Integration - Based
6.000 Integration - Based
6.980 Sound

GC Temperature Program
Initial Temp | Hold | Ramp | Final Temp
200 | 0 | 25 | 250
250 | 0 | 15 | 310
140 | 1 | 0 | 140

Integration
Peak: 90.00%
Base line: 75.00%
Area reject: 10.000
Standard weight: 4.000
Sample weight: 100.000

Here’s what a chromatogram from one of our calibration runs looks like:

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We only calibrate for CBD, THC, CBG, and CBN as that’s all we presently care about.

Happy testing.

19 Likes
2

and that is CBD and CBC that you’re not getting baseline separation on?

elution: THCV, CBDV, CBL, CBD, CBC, D8,D9, GBG, CBN ?!?

7 Likes
3

That sounds correct. I’ll try to remember to check the peak order next time I’m in the analytical lab, I believe we’ve got a chromatogram up on the wall with each peak labelled.

Now that we’ve got the HPLC up and running the GC mostly sees work doing residual solvent testing.

5 Likes
4

How is the 310 going for you a year later?

1 Like
5

We sold it as it got very little use after we got our HPLC dialled in.

4 Likes