The Drug Chemists at the Vermont Forensic Laboratory perform tests to determine the identity of marijuana, powders, tablets, and liquid submitted by Vermont law enforcement officers and investigators. In many cases, these items are illegal drugs or prescription drugs stolen or diverted for abuse purposes. In other cases the specimens are suspected poisons or contaminants. The analysis of suspicious plants involves microscopic examination and Thin Layer Chromatography. By observing the plant under magnification, the Forensic Chemist is able to identify characteristics consistent with marijuana. A few of these characteristics include cystolythic hairs (bear claws), thick walled conical trichomes, glandular hairs, fluted stems, resin, seeds (see scanning electron microphotographs of marijuana). Marijuana is often submitted in various forms (leaves, buds, hand-rolled cigarettes, residue, hash, added to food products, etc). To confirm the microscopic examination of the plant material, the Forensic Chemist performs a second test called Thin Layer Chromatography or GC/MS.
Unknown powders, liquids, tablets, and residues undergo different types of analysis. Typically, these substances are first analyzed using color spot tests. These simple chemical tests help the chemist by providing an initial "presumptive" identification of the unknown substance, to be followed by other more sophisticated and informative types of testing. Color tests such as Cobalt Thiocyanate are very useful to the drug chemist but are not used alone for Forensic drug identification. Our procedural guidelines dictate that all drug identifications utilize another method of analysis, particularly one that provides information about the chemical structure of the compound. Our methods of structural identification include Gas Chromatography/ Mass Spectrometry (GC/MS) and Fourier Transform Infrared Spectrophotometry (FTIR).