Archive for the ‘Cannabis’ Category

Accurate Quantification of Cannabinoid Acids and Neutrals by GC – Derivatives without Calculus

Derivatization is a widely-used technique for GC sample preparation across many industries and in widely varied matrices from soil to plastics to blood that is used to make polar and active compounds more amenable to good GC analysis. If you’re careful about testing your derivatization procedure during method development, you can be confident that you’ll […]

Accurate Quantification of Cannabinoid Acids by GC – Is it Possible?

I think by now we’ve all heard that GC potency testing for cannabis or hemp has some drawbacks. That being said, GC is a popular, rugged, and cost-effective laboratory workhorse and is still employed in many cannabis laboratories. The major drawback of GC versus HPLC cannabinoid testing is the fact that the acidic cannabinoids convert […]

Terpenes in Cannabis – to MS or not to MS?

In my last blog, I showed how FID is a more suitable detection method for cannabis residual solvent analysis than MS. But what about terpene analysis? Can our old friend the FID hold its ground against the mighty mass spectrometer for this application? Actually, it can! Terpenes are much larger molecules than residual solvents, so […]

Residual Solvents in Cannabis – to MS or not to MS?

Over the past few months, I’ve gotten numerous questions about the best detection method for terpenes and residual solvents in cannabis. It seems that a lot of people are purchasing GC-MS instruments for both of these analyses. While GC-MS is indeed a powerful tool, it’s not really necessary for either analysis. In fact, the use […]

Medical Cannabis Terpenes Standards now available from Restek!

As many of you dedicated ChromaBLOGraphy readers know, Restek has supported the medical marijuana market for years with reference materials, and GC and LC consumables.  We find the field fascinating, so much so that we try to anticipate the upcoming needs of medical cannabis analysts through method development for compounds in addition to cannabinoids that […]

Comparison of Phencylidine and Prazepam as Internal Standards in Medical Cannabis Potency Analysis with GC-FID

Recently in the ChromaBLOGraphy posts below I proposed the use of Phencylidine (PCP) as an internal standard (ISTD) for cannabinoids analysis with GC-FID when using the Rxi-35Sil MS GC column.  I demonstrated that the RSD% of Average Response Factors (Avg RFs) and Correlation Coefficients (CCs) for the calibration curves generated using the ISTD technique were […]

Cannabis Analysis – We’ve Come a Long Way, Baby!

A little less than a year ago at Pittcon in Chicago, my colleague Frank Dorman from the Pennsylvania State University and I sat down over beers with Ken Snoke and Wes Burk from Emerald Scientific, a small startup distribution business for cannabis labs. We were joined by Bill and Christi Schroeder and Ted Flood from […]

Internal Standard versus External Standard Quantification in Medical Cannabis Potency Analysis with GC-FID

The ChromaBLOGraphy series continues for the use of internal standards with medical cannabis potency testing by GC-FID (I’ve listed the first two parts in the series immediately below as web-links).  This third part demonstrates the positive impact an internal standard can have on quantitative accuracy. Possible Internal Standards for Medical Cannabis Potency Testing by GC […]

Calibration Curves for Cannabinoids Based on PCP Internal Standard – Medical Cannabis GC-FID

Yesterday’s ChromaBLOGraphy post concerned the use of internal standards (ISTDs) for GC-FID potency testing of medical cannabis.  In that post I defined desirable characteristics for an ISTD and said that one of the benefits of ISTD use is better quantitative accuracy.  Good quantitative accuracy starts with good calibration, which I demonstrate in this post by showing a […]

Possible Internal Standards for Medical Cannabis Potency Testing by GC

I am often asked about internal standards for use in medical cannabis potency testing with gas chromatography.  I finally got some time in the lab to check this out and came up with a couple of possibilities after testing numerous compounds for favorable retention times versus typically analyzed cannabinoids. Internal standards are mostly used by adding to […]