Presumptive tests cannabis

Presumptive tests for cannabis products are used to test for the presence (or otherwise) of phenolic cannabinoids. The principle one that is used is the Duquenois-Levine test. An alternative which is available and can also be used is the Corinth IV salt test. Both involve a reaction between the cannabinoids and a test reagent to form coloured products. Positive and negative control tests should also be carried out. 

Other presumptive tests are available for the tentative identification of cannabis [8] but these are not specific to this controlled substance because a wide range of plant materials also contain phenolic compounds which result in similar reactions to those obtained from cannabis. As a consequence, further methodologies must be used to identify the materials. 

Marijuana (herbal cannabis) is the most common illegal dmg in the world. Seizures have increased globally with the Americas accounting for the highest share (1). U.S. seizures of marijuana alone exceed 1 million kilograms each year (6). Evidence submitted to forensic laboratories is screened for marijuana by microscopic inspection and simple chemical tests such as the Duquenois-Levine test. Presumptive positive results are confirmed by GC/MS to positively identify cannabinoids, including... 

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