(BQ) Part 2 book “Basic principles of forensic chemistry” has contents: Phenethylamines, tertiary amines, tryptamines, anabolic steroids, miscellaneous controlled substances, clandestine operations - synthetic methods, hazards, and safety, evidence identifi cation and collection, examination of clandestine evidence. | Part III Examination of Drugs/Narcotics Cannabis 12 Introduction Marijuana is not a scientific classification; it is a term typically used to describe the dried leaves of cannabis plants and flowering portions of the female cannabis. Cannabis contains the psychoactive drug tetrahydrocannabinol which acts on the central nervous system producing both physical and psychological effects. The trans-D9-isomer is the main active form of tetrahydrocannabinol (THC) (Fig. ). The delta-nine symbol (D9) indicates the presence of a carbon–carbon double bond (D) located between carbons 9 and 10 (exponent is the first carbon in the double bond). This terminology is used quite often in organic chemistry and biochemistry where it is frequently encountered in the abbreviated forms of fatty acids. The transD9-isomer is classified in the controlled substance act and is the form most often referred to when using the acronym THC. It can be extracted from the herbal form of cannabis using a variety of techniques. The chosen method of extraction determines the overall concentration of THC in the final product as well as its physical appearance. Marijuana is described above and typically contains 7–25% THC. Hemp is a form grown for industrial (nondrug) purposes and the concentration of THC (less than 1%) is typically too low to produce euphoric effects. Hashish (hash) is a THC resin extracted from the female flowers and is somewhat more concentrated than marijuana. Hash oil is a more concentrated form of hashish and can easily approach 50% THC content. Kief is a powder form commonly called (incorrectly) crystal or pollen. It contains a THC content comparable to that of hash; in fact, a type of hash is produced from highly compressed kief. Resin is a thick tar by-product of smoking cannabis and contains trace amounts of THC. Smoking resin vapors can cause irritation to the throat and lungs. Historically, THC has been the most frequently analyzed controlled substance in .
