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A new voltammetric method for the determination of Δ(9)-tetrahydrocannabinol (Δ(9)-THC) is described. The voltammetric experiments were accomplished in N-N dimethylformamide/water (9:1, v/v), using tetrabutylammonium tetrafluoroborate (TBATFB) 0.1mol/L as supporting electrolyte and a glassy carbon disk electrode as the working electrode. The anodic peak current was observed at 0.0V (vs. Ag/AgCl) after a 30s pre-concentration step under an applied potential of -1.2V (vs. Ag/AgCl). A linear dependence of Δ(9)-THC detection was obtained in the concentration range 2.4-11.3ng/mL, with a linear correlation coefficient of 0.999 and a detection limit of 0.34ng/mL. The voltammetric method was used to measure the content of Δ(9)-THC in samples (hemp and hashish) confiscated by the police. The elimination of chemical interferences from the samples was promptly achieved through prior purification using the TLC technique, by employing methanol/water (4:1, v/v) as the mobile phase. The results showed excellent correlation with results attained by HPLC.

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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.

In this work a new model of carbon paste electrode was employed to determine sulfamethoxazole (SMX), an antibiotic used to treat infections in human and veterinary medicine, by the square wave voltammetric modality (SWV). More specifically, the electrochemical behavior of SMX was investigated by cyclic voltammetry (CV),

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