Development of a Pencil Drawn Paper-based Analytical Device to Detect Lysergic Acid Diethylamide (LSD)*, †.

The need for agile and proper identification of drugs of abuse has encouraged the scientific community to improve and to develop new methodologies. The drug lysergic acid diethylamide (LSD) is still widely used due to its hallucinogenic effects. The use of voltammetric methods to analyze narcotics has increased in recent years, and the possibility of miniaturizing the electrochemical equipment allows these methods to be applied outside the laboratory; for example, in crime scenes. In addition to portability, the search for affordable and sustainable materials for use in electroanalytical research has grown in recent decades. In this context, employing paper substrate, graphite pencil, and silver paint to construct paper-based electrodes is a great alternative. Here, a paper-based device comprising three electrodes was drawn on 300 g/m2 watercolor paper with 8B pencils, and its efficiency was compared to the efficiency of a commercially available screen-printed carbon electrode. Square wave voltammetry was used for LSD analysis in aqueous medium containing 0.05 mol/L LiClO4 . The limits of detection and quantification were 0.38 and 1.27 µmol/L, respectively. Both electrodes exhibited a similar voltammetric response, which was also confirmed during analysis of a seized LSD sample, with recovery of less than 10%. The seized samples were previously analyzed by GCMS technique, employing the full scan spectra against the software spectral library. The electrode selectivity was also tested against 3,4-methylenedioxymethamphetamine (MDMA) and methamphetamine. It was possible to differentiate these compounds from LSD, indicating that the developed paper-based device has potential application in forensic chemistry analyses.

The Application of Voltammetric Analysis of Δ(9) -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 ∆(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.