They do extract terpenes and add them to whatever medium everyday in the perfume industry and have been doing it for quite a while.
All of you BHO and CO2 experts should really check real professional extractor. If you think for a minute that the techniques you are trying to reinvent were specifically engineered to capture the most volatile terpenes, you may wonder why your results are opposite.
An excellent 6 volume book series on the subject is The Essential Oils, by Ernest Guenther.
We visited The Essential Oil Company in Sellwood, an outlying Portland community (
http://www.essentialoil.com/ ) and shared techniques with Boris, the owner. They remove their essential oils using saturated steam.
Besides The Essential Oil Company, check out Lebermuth Company, a major world supplier of essential oils. They also have sophisticated labs for developing fragrances and flavors.
http://lebermuth.com/
More directly related to cannabis, check out the more recent papers by Dr Justin Fischedick on cannabis terpenes. From the recent lecture posting, that we sponsored him at.
Dr. Fischedick received both his Masters degree and PhD at Leiden University in the Netherlands where he worked on numerous projects related to medicinal cannabis. He is currently a post-doctoral research associate at Washington State University studying other plants that produce medicinally valuable terpenoids. His scientific publications in the area of cannabis research include:
Fischedick, J.T., Hazekamp, A., Erkelens, T., Choi, Y.H., Verpoorte, R., 2010. Metabolic fingerprinting of Cannabis sativa L, cannabinoids and terpenoids for chemotaxonomic and drug standardization purposes. Phytochemistry 71, 20582073.
Fischedick, J., Van Der Kooy, F., Verpoorte, R., 2010. Cannabinoid Receptor 1 Binding Activity and Quantitative Analysis of Cannabis sativa L. Smoke and Vapor. Chem. Pharm. Bull. 58, 201207.
Fischedick, J.T., Glas, R., Hazekamp, A., Verpoorte, R., 2009. A Qualitative and Quantitative HPTLC Densitometry Method for the Analysis of Cannabinoids in Cannabis sativa L. Phytochem. Anal. 20, 421426.
Hazekamp, A., Fischedick, J.T., 2012. Cannabis from cultivar to chemovar. Drug Test Anal 4, 660667.
Hazekamp, A., Fischedick, J.T., Díez, M.L., Lubbe, A., Ruhaak, R.L., 2010. 3.24 Chemistry of Cannabis, in:Editors-in-Chief: Lew Mander, Hung-Wen (Ben) Liu (Eds.), Comprehensive Natural Products II. Elsevier, Oxford, pp. 10331084.