Cannabinoid mass fragments

J. E., Leander, K., and Widman, M. Quantification of Cannabinoids in Human Blood Plasma by Mass Fragment ography... 

In this instrument, the assay programs are "calibrated" by injection of pure reference standards. The relative intensities of the mass lines selected for specific identification of each individual cannabinoid (7), as well as the quantity scale factor and nominal retention time for each compound, are thereby entered into the computer memory. In automatic operation, the computer instructs the spectrometer to search for the characteristic fragment ions only during a time window near the nominal GC retention time for the compound. 

The X-ray crystal structure of A1 -tetrahydrocannabinolic acid B is reported,362 and one of the previously reported (Vol. 4, p. 75) dihydrobenzofurans from the citric acid-catalysed condensation of orcinol with menth-4-en-3-ol is shown to be (256) by X-ray analysis.363 G.c.-m.s. assay of A -THC-OMe allows the detection of 1 ng mP1 plasma of A -THC.364 The mass spectral fragmentation of A -THC, A6-THC, and some isomeric cannabinoids to the prominent m/e 231 ion has been examined.365 Miniaturized syntheses of 32 natural, or potentially natural, cannabinoids are reported in connection with their chromatographic analysis.366... 

Routine, but useful, interpretations of the mass spectral fragmentation patterns under electron impact have been reported for esters of the menthane and camphane series,39-40 for thioketones with the thujane, pinane, camphane, and fenchane skeleta,41 for [2H]limonene,42 for cannabinoids,43-46 and for the volatile components from Pinus seedlings.47... 

Fig. 6 shows a chromatogram of THC, the active component of cannabis (Formula B), recorded by mass specific detection of the ions 314 (M ), its isotope 315 (lower trace) and 299 (M -15). The identity of the drug is given by the retention time and the intensity ratios between the recorded ions. They must correspond to the respective peak ratios of the mass spectrum taken under the same conditions, in this case at 20 eV. The spectrum is shown in Fig 7. Fragment 299 corresponds to almost 60% of the molecular ion. M -1 is 23% as intense as M, as can be expected from the 20 carbons in the molecule. With this approach, THC and other cannabinoids can be detected in a tiny trace of dust. Fig. 8 shows the chromatogram of a hexane extract of such a powder. The mass recording 314 and 299 indicate the presence of cannabidiol and THC, the mass recording 295 is used for the detection of cannabinol which forms the big last peak. Differentiation between cannabidiol and THC is possible with the peak intensity ratio which is low for cannabidiol (first peak) and 60% in favor of 314 for THC. 

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