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Cannabis has been used as a medicinal plant for thousands of years. There are now over 700 varieties of cannabis that contain hundreds of compounds, including fatty cannabinoids that are the main biologically active constituents and volatile terpenes that have distinct odors. This is a selective review that includes important examples of the analysis and study of cannabis and its components and synthetic cannabinoids by thin layer chromatography (TLC) related to its medical and recreational uses. The TLC methods described in this review complement the more expensive and difficult to perform and sustain high performance liquid chromatography (HPLC), HPLC/mass spectrometry (HPLC/MS), gas chromatography (GC), and GC/MS methods. These TLC methods are especially valuable and often sufficient for use in resource-limited countries. Since this is apparently the first review devoted only to the TLC of cannabis in the literature, even earlier TLC references have been included for completeness. [ABSTRACT FROM AUTHOR]

Thin-layer chromatography (TLC) had its initial growth in the 1950s when TLC sorbents and devices for making TLC plates in the analytical laboratory became available. A resurgence in TLC use occurred when commercially prepared plates became available around 1965. Their advantage was greater reproducibility because of their uniformity and convenience of use. Having just passed the 50th anniversary of this date, TLC still finds wide application as a useful analytical tool throughout the world. The introduction of high-performance TLC (HPTLC)-prepared plates was also a welcome addition to the chromatography laboratory. Today, advances in TLC instrumentation that aid in sample application, plate development, qualification, and quantification continue to evolve and improve. The TLC/HPTLC plate manufacturers have continued to add new prepared plates to meet the greater demands for higher purity or special applications for these newer devices. More recently, researchers have experimented with new sorbents or preparation techniques that have resulted in special properties for thin-layer-prepared plates, particularly for use in TLC–MS applications. This article will discuss not only some classical TLC plates but also these newer thin layers, their advantages, and some of their applications. [ABSTRACT FROM PUBLISHER]