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

Abstract

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 ∆(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 ∆(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 ∆(9) -THC even in the presence of the Fast Blue B salt, which avoided false positive results for all the studied extract plants.

Disposable 3D Printed Electrode for the Electrochemical Detection of Delta-9-Tetrahydrocannabinol in Aqueous Solution and 11-Nor-9-Carboxy-Tetrahydrocannabinol in Saliva

“…The literature involving voltammetric determination of Δ9-THC comprehends the use of electrodes with and without chemical modification. There are methodologies for its detection when in seized samples [26][27][28][29][30] , and in saliva 31,32 . However, it should be noted that in the literature only a few studies with artificial saliva have been reported for the electrochemical detection of Δ9-THC 33 .…”

Portable testing techniques for the analysis of drug materials

“…Electrochemical sensors can be classified based on the type of electrochemical transducer employed. Voltammetry is the most widely used transduction event for the rapid quantitative sensing of illicit drugs with studies performed on NBOMes in blotter samples (Oiye et al, 2017), cocaine residue (Tavakkoli et al, 2019), and Δ 9 ‐tetrahydrocannabinol in plant matter (Balbino et al, 2016). Highly sensitive amperometric detection of morphine has used a modified screen‐printed electrode (Maccaferri et al, 2019), while the sensitive impedimetric detection of cocaine using molecularly imprinted polymer nanoparticle receptors showed no cross reactivity with morphine (D'Aurelio et al, 2020).…”

Recent developments in electrochemical detection of illicit drugs in diverse matrices

“…The glassy carbon electrode was found superior due to a lower LOD in comparison to the platinum working electrode (6.2 x 10 -10 vs 2.7 x 10 -8 for the glassy carbon and platinum electrode, respectively). Later Balbino et al (2016) published a CV-method using the same type of glassy carbon electrode for the detection of Δ9-THC in suspected marijuana plants. The same accumulation time of 30 s was kept.…”