Rxi-35Sil MS GC column for fast separations of CBC, CBD, delta-8-THC, delta-9-THC, CBG, and CBN with hydrogen carrier
gas. This same separation can be done on a
15m x 0.53mm x 0.50µm Rxi-35Sil MS
, a column format that has additional sample
loading capacity and ruggedness, at the cost of slightly longer run times. We also have a
15m x 0.53mm x 0.50µm Rtx-35
, a
35% pendant phenyl-type column that doesn’t have the arylene-modification that the 35Sil MS uses for increased thermal
stability. (The 35 has a 300°C maximum operating temperature and the 35Sil MS can go to 360°C!) Sometimes the arylene-
modified columns and the pendant-only columns can differ in selectivity, but in this case the chromatograms are very close to
each other.
One novel twist I put on this work was to prepare a standard that had different relative concentrations of cannabinoids.
Although the variation of concentrations in medical cannabis can range somewhat widely based on strain, I decided to stagger
the concentrations from high to low as delta-9-THC, cannabidiol, cannabigerol, cannabichromene, delta-8-THC, cannabinol.
This potentially allows more accurate determination of cannabinoids versus using a standard that is equal in concentration for
all compounds, considering even that the flame ionization detector probably has the widest linear dynamic range for GC. This
variable concentration -standard also allows elution order mapping/confirmation of cannabinoids for GC columns (and LC
columns). You can build your own “JC Mix” with individual cannabinoid standards located on our
Medical Marijuana web
page
.
Medical Marijuana « ChromaBLOGraphy: Restek's Chromatography Blog
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02/08/2014 5:05 P
