Options for Analysis
We can choose between analyzing these compounds by UPLC/MS, HPLC/MS and GC/MS
Many Different Compounds of Interest
There are different cannabinoids, including THC, THCA, CBD, CBDA, CBG, CBN and CBC, each with different peaks in chromatograms.
Issues with GC/MS here
THCA and CBDA are not biologically available and need to be decarboxylated before consumption.
Mini-conclusion
We don't care for THC, but not to ensure that the quantities are under 0.3% (THC + THCA) but we need to quantify available CBD, and GC would decarboxylate the CBDA when volatilizing it. Therefore, HPLC is the better option here.
Pesticide Analysis in CBD Hemp
Many columns can be used for HPLC-MS separation of cannabinoids. The Agilent 959961-902 has been used here (page 4) while Sigma-Aldrich has outlined multiple other columns which can be used for terpene, cannabinoid, and pesticide analysis here (pages 6, 9 and 12 respectively). This Sigma-Aldrich paper has good outlines for pesticide, terpene and cannabinoid standards, and will be referenced heavily as this is what good looks like.
The certified reference materials for the cannabinoids of interest are THC, THC-A, CBD, and CBD-A. These can all be obtained from Sigma-Aldrich, under the term 'analytical sample', and of the names Δ9-Tetrahydrocannabinol solution, Delta9-Tetrahydrocannabinolic acid A solution, Cannabidiol solution, and Cannabidiolic acid solution.
Included below, there are two figures from within the Sigma-Aldrich Cannabis Testing outline. The ones on the left outline different standards for cannabinoid quantification as well as usable columns. On the right are two examples of HPLC runs with UV detectors for cannabinoid quantifications and peak labeling.