Naturally occurring cannabinoids previously impossible to separate and analyze were quantitated on a routine basis using silylation. Relative retention times of many silylated cannabinoids are reported for the first time.
Keyphrases Cannabinoids-silylation and GLC separation 0 Cannabis satiua L.-silylation and GLC separation of cannabinoids GLC-analysis, C. satiua constituents Claussen et al.
(1) used trimethylsilyl derivatives to separate some cannabinoids from their corresponding carboxylic acid analogs. However, at the time of this report, isolation of cannabinoids with subsequent identification by synthesis and combined GLC-mass spectrometry was in an embryonic state. Thus, Claussen et al. (1) were unable to identify many peaks in the chromatogram.
Later, Heaysman et al.
(2) examined the constituents of Cannabis using silyl derivatives, and they reported retention times for the trimethylsilyl ethers of cannabidiol, (-)-Ag-trans-tetrahydrocannabinol, and cannabinol. Caddy and Fish (3) compared the GLC separation obtained for underivatized cannabidiol, (-)-A9-trans-tetrahydrocannabinol, and cannabinol with their trimethylsilyl and trifluoroacetyl derivatives. Other investigators (4, 5) described a trimethylsilyl method for the analysis of cannabidiol, (-)-Ag-trans-tetrahydrocannabinol, and (-)-Agtrans-tetrahydrocannabinolic acid.
Paris and Paris (6) reported the identification of cannabidiolic acid as its trimethylsilyl ester-ether derivative in a sample of hashish, and the use of silyl derivatives to obtain a clear and discrete separation of synthetic cannabidiol and cannabichromene was reported (7); separation of the bis(trimethylsily1) ether of synthetic cannabidiol from the mono(trimethylsilyl) ether was also obtained. The use of trimethylsilyl derivatives to separate the equatorial and number cannabinoid 0-R? R I cannabidivarin H C3H7 -Si(CH3) 3 I11 cannabidiol H CSHII -Si(CHd3 V I I I cannabidivarinic C02Si(CH3)3 C3H7 -Si(CH3)3