Utilization of an Electrochemiluminescence Sensor for Atropine Determination in Complex Matrices

Abstract

A major challenge within forensic science is the development of accurate and robust methodologies that can be utilized on-site for detection at crime scenes and can be used for analyzing multiple sample types. The recent expansion of electrochemical sensors to tackle this hurdle requires sensors that can undergo analysis without any pretreatment. Given the vast array of samples that are submitted for forensic analysis, this can pose a major challenge for all electrochemical sensors, including electrochemiluminescent (ECL)-based sensors. Within this contribution, we demonstrate the capacity for an ECL-based sensor to address this challenge and it is potential to detect and quantify atropine from a wide range of samples directly from herbal material to spiked solutions. This portable platform demonstrates satisfactory analytical parameters with linearity across a concentration range of 0.75 to 100 μM, reproducibility of 3.0%, repeatability of 9.2%, and a detection limit of ∼0.75 μM. The sensor displays good selectivity toward alkaloid species and, in particular, the hallucinogenic tropane alkaloid functionality within complex matrices. This portable sensor provides rapid detection alongside low cost and operational simplicity, thus, providing a basis for the exploitation of ECL-based sensors within the forensic arena.

Datura quids at Pinwheel Cave, California, provide unambiguous confirmation of the ingestion of hallucinogens at a rock art site

“…Extraction of both the quids and dried Datura leaf material, utilized as a control, was performed to extract any atropine and scopolamine present within the solid material. Both acidic (46)(47)(48)(49) and alkaline-based extraction (50, 51) methods utilizing a range of solvents have previously been performed to varying degrees of success for the extraction of the tropane alkaloids from leaf (48,49), flower (47), root (51), seeds (47,49,50,52), and stem (47,49) material of Datura plants. A set of mixed standards containing atropine, scopolamine, and mexiletine hydrochloride, utilized as an internal standard, prepared within the extraction solvent methanol, were analyzed by reverse phase liquid chromatograph−mass spectrometry (LC-MS) with both ultraviolet (UV) (214-nm detector wavelength) and mass spectrometry detection.…”

Voltammetry as a rapid screening method for NPS identification

“…The major challenge, highlighted by this contribution is the need to discriminate between structurally similar compounds. This has been examined for other illicit substances [16][17][18][19] but research on SCs is still limited in this area. In addition, street samples of SCs are likely to contain other illicit substances, notably amphetamine type substances (ATS).…”

Psychoactive Substances and How to Find Them: Electrochemiluminescence As a Strategy for Identification and Differentiation of Drug Species

“…However, this single luminophore approach often prevents the successful differentiation of structurally similar compounds, which typically interact with the complex via analogous mechanisms producing emission within the same potential regions. 11,21,22 Employment of multi-luminophore sensors utilising several different metal complex luminophores as well as pH-controlled emission offer viable approaches to tackle the limited specificity associated with ECL techniques. Prior work has demonstrated the ability to exploit differences in the relationship between pH and luminescence intensity, to produce a system whereby two structurally similar species, atropine and scopolamine, could both be identified within a mixed sample.…”

“…[23][24][25][26][27][28][29][30][31][32] Previous studies have mostly involved tri-n-propylamine (TPA), the workhorse of anodic co-reactant ECL, with iridium and osmium complexes producing efficiencies comparable or indeed superior to those of the traditional [Ru(bpy)3] 2+ luminophore. [23][24][25][26][27][28][29][30][31][32] To date, a range of illicit and alternative drug substances have been detected down to forensically and clinically relevant ranges via ECL, including atropine 21,22,[33][34][35][36] , scopolamine 21,37 , ketamine 38 , amphetamine-type stimulants (ATS) 11 and cocaine. 34,[39][40][41][42][43][44][45] However, few investigations into the detection of multiple analytes within the same sample matrix have been performed, due to the inherent lack of specificity offered by ECL This is problematic for the screening of typical street samples that may contain a variety of structurally related drugs, in addition to diluents or adulterants.…”