The Application of Voltammetric Analysis of Δ9-THC for the Reduction of False Positive Results in the Analysis of Suspected Marijuana Plant Matter

The development of methodologies using inexpensive, fast, and reliable instrumention is desirable in illicit drug analysis. The purpose of this study was based on cyclic voltammetry technique to differentiate the electrochemical behavior of Delta(9)-THC, the psychoactive substance in marijuana, and five different extract plants to yield false positive results after analysis protocol for cannabinoids using thin-layer chromatography and Fast Blue B salt. After applying a deposition potential of -0.5 V in a glassy carbon working electrode, the results indicated an anodic peak current at 0.0 V versus Ag/AgCl after addition of Delta(9)-THC solution in the electrochemical cell, and limits of detection and quantification were 1.0 ng mL(-1) and 3.5 ng mL(-1), respectively. Other interfering plants showed distinct amperometric responses. This methodology was useful to detect Delta(9)-THC even in the presence of the Fast Blue B salt, which avoided false positive results for all the studied extract plants.