Erowid References Database
“Validation of a Gas Chromatography Method for Analysis of Medicinal-Quality Cannabis”.
Why was this Study Necessary? Since the passage of California’s Compassionate Use Act (Proposition 215) in 1996, Cannabis products have become available for medical applications. Scientific inquiries into the quality, safety and medical use of Cannabis are re-emerging with renewed acceptance of this botanical medicine (Pertwee 2004; Stott and Guy 2004; Ben Amar 2006; Wright 2007). Understanding of the roles of genetics and plant management have dramatically increased the potency of medicinal strains (de Meijer et al. 1992, 2003, 2005; Hazekamp 2007; Pacifico et al. 2008), and marked divergence of potency from historical norms and international collections is now common (Turner et al. 1979; Lopes de Oliveira et al. 2008). We have initiated development of chemical analysis methods for Δ9-tetrahydrocannibinol (Δ9-THC) and related compounds in medicinal Cannabis available at dispensaries in our region, to better understand how improved genetics and growing practices have affected the potency and composition of available medicinal strains.
The vast majority of research into analysis of Cannabis products (marijuanas, hashish, ganja, etc.) was published in the 1960s and 1970s during the early growth of gas chromatography (GC) and gas chromatography/mass spectrometry (GC/MS). These analytical tools have significantly improved since that time, but the most modern instrumention has largely been focused on high-sensitivity cannabinoid analysis of biological fluids for clinical and forensic applications. These resulting “trace” measurement methods might not necessarily be applicable to analysis of high concentration medicinal Cannabis samples, and this needs verification. Moreover, there is controversy regarding the actual potency of modern strains of Cannabis (Hazekamp 2007); for these reasons we initiated a study to evaluate the reliability of a gas chromatography-based method to produce accurate and reproducible quantitative data on the Δ9-THC content of medicinal Cannabis.
This study has three parts: 1) Development of basic analytical technique for cannabinoid extraction and analysis; 2) Preparation of highly purified ‘natural-source’ cannabinoid fractions and verification of instrument response to commercial standards and natural-source materials; 3) Comparison of GC and gravimetric methods for estimation of Δ9-THC content.
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