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

Abstract

Currently, marijuana or cannabis is the most consumed drug worldwide, and is also the one with the highest number of seizures, with 354 tons seized in Brazil in 2017. The increase in its consumption has been called attention, not only by the authorities, due to accidents caused when driving under the influence of the drug, but also by companies that carry out toxicological analyzes on their employees. For this, rapid tests, such as colorimetric tests, are generally used to analyze the urine of users. The need for agile and proper identification of drugs of abuse has encouraged the scientific community to improve and to develop new methodologies. Electrochemical methods appear as a cheap, portable and easy to use alternative. The use of biodegradable materials for the development of disposable electrodes has become paramount today. The use of 3D printers emerges as an alternative for the manufacture of these electrodes and the use of saliva instead of urine, has also been a priority because it is a less invasive sample and difficult to adulterate. In this work, a three dimensional device was created in an innovative way containing the three electrodes, working, counter and reference, in conductive material. The device was then used to detect the active principle present in cannabis, delta-9-tetrahydrocannabinol, in aqueous solution, and its metabolite, 11-nor-9-carboxy-THC, in samples of real saliva, both through cyclic voltammetry. The positive results show that the proposed device can be used, as well as those already found on the market, for the identification of drug use and in the forensic field.

Keywords

• Forensic electroanalysis
• Delta-9-tetrahydrocannabinol
• Saliva
• Voltammetry
• 3D-printed electrode