Designer drugs, also commonly known as new psychoactive substances (NPS), are increasingly in their prevalence and a challenge to toxicologists and forensic chemists. Synthetic cannabinoids (SCs) are among the largest group of NPS that have emerged in the illicit drug market all over the world. SCs may consist of different chemicals prepared in laboratories and herbal mixtures that said to be incense and not-for-human-consumption. The main aim of this paper is to investigate the use of electrochemical based methods for screening some of the emerging types of SC. More specifically, the paper takes electrochemistry approach called voltammetry to perform the detection and analysis of SCs whereby the main subjects for screening include STS-135 and 5F-ADB-PINACA. The expected result is that those compounds that belong to the same class should indicate almost similar behaviour to help achieve its objective, the paper reviews a number of recent publications relating to forensic drug analysis and much attention to electrochemical sensor methods.
We have studied an electrochemical detection method for the stimulants in the forensic samples using electrochemiluminescence (ECL). In this context, amphetamine type stimulant (methamphetamine (MA)) has been studied as coreactants in the [Ru(bpy)3]2+ (where bpy is 2,2’-bipyridine) ECL system. This approach is developed based on a glassy carbon electrode modified with [Ru(bpy)3]2+ /Nafion composite film. LoD, LoQ and linear working range for MA are studied currently. The ECL intensity was found to be concentrations over the range of 5 x 10-8 to 2.5 x 10-4mol/L. LoD for MA is 1.94 x 10-10 mol/L. The regression coefficient is 0.9931 for the experiment. Our approach was applied in different medium such as saliva and human serum to detect MA This technique is simple, rapid, selective and sensitive, and shows potential for the highthroughput quantitation of MA. the results show that the present electrochemical approach seems to provide a sensitive detection of MA in forensic applications.
Thin films of the metallopolymer [Os(bpy)2 (PVP)10]2+, where bpy is 2,2'-dipyridyl and PVP is poly(4-vinylpyridine), luminesce at 750±12 nm upon excitation at 355nm. The luminescence decay responses can be described by a double exponential decay model in which the limiting lifetimes are 75±14 (population fraction of 0.9) and 35±8 ns (population fraction of 0.1) for films in contact with aqueous 0.1 M H2SO4. Electrochemistry has been used to create well defined concentrations of the luminescence quencher, Os3+, within the films. Time resolved spectroscopy reveals that both dynamic and static processes contribute to luminescence quenching with a rate constant for electron transfer between the photoexcited Os2+* and the Os3+ centres of 1.3x107 M-1s-1 being observed. Stable gold nanoparticles have been created within the metallopolymer by the chemical reduction of tetrachloroaurate. These nanocomposite materials exhibit enhanced emission intensity compared to the gold free films.