Tale of Two Alkaloids: pH-Controlled Electrochemiluminescence for Differentiation of Structurally Similar Compounds

Brown, Kelly; Jacquet, Charlotte; Biscay, Julien; Allan, Pamela; Dennany, Lynn

doi:10.1021/acs.analchem.9b04922

Cited by 24 publications

(58 citation statements)

References 54 publications

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“…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).…”

Section: Resultsmentioning

confidence: 99%

Voltammetry as a rapid screening method for NPS identification

Ameen

Russell

Dennany

2020

Emerging Imaging and Sensing Technologies for Security and Defence V; And Advanced Manufacturing Technologies for Micro- And Na

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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.

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Section: Resultsmentioning

confidence: 99%

Voltammetry as a rapid screening method for NPS identification

Ameen

Russell

Dennany

2020

Emerging Imaging and Sensing Technologies for Security and Defence V; And Advanced Manufacturing Technologies for Micro- And Na

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“…Therefore, there is need to develop a rapid, inexpensive detection method for detection of 5-HT. Electrochemical methods have been highlighted as a viable method to address these points and develop a rapid, portable detection of a range of analytes 15 – 17 including 5-HT determination primarily due to their simple design, cost effectiveness, dynamic response, good selectivity, sensitivity 18 , etc. The combinations of these approaches with different NCs for electrochemical 5-HT sensing studies have been explored.…”

Section: Introductionmentioning

confidence: 99%

Structural refinement and electrochemical properties of one dimensional (ZnO NRs)1−x(CNs)x functional hybrids for serotonin sensing studies

Mullani

Dhodamani

Shellikeri

et al. 2020

Sci Rep

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Herein, the efficient serotonin (5-HT) sensing studies have been conducted using the (ZnO NRs)1−x(CNs)x nanocomposites (NCs) having appropriate structural and electrochemical properties. Initially, the different compositions of ZnO nanorods (NRs), with varying content of carbon nanostructures (CNs=MWCNTs and RGO), are prepared using simple in-situ wet chemical method and thereafter these NCs have been characterized for physico-chemical properties in correlation to the 5-HT sensing activity. XRD Rietveld refinement studies reveal the hexagonal Wurtzite ZnO NRs oriented in (101) direction with space group ‘P63mc’ and both orientation as well as phase of ZnO NRs are also retained in the NCs due to the small content of CNs. The interconnectivity between the ZnO NRs with CNs through different functional moieties is also studied using FTIR analysis; while phases of the constituents are confirmed through Raman analysis. FESEM images of the bare/NCs show hexagonal shaped rods with higher aspect ratio (4.87) to that of others. BET analysis and EIS measurements reveal the higher surface area (97.895 m2/g), lower charge transfer resistance (16.2 kΩ) for the ZCNT 0.1 NCs to that of other NCs or bare material. Thereafter, the prepared NCs are deposited on the screen printed carbon electrode (SPCE) using chitosan as cross-linked agent for 5-HT sensing studies; conducted through cyclic voltammetry (CV) and square wave voltammetry (SWV) measurements. Among the various composites, ZCNT0.1 NCs based electrodes exhibit higher sensing activity towards 5-HT in accordance to its higher surface area, lower particle size and lower charge transfer resistance. SWV measurements provide a wide linear response range (7.5–300 μM); lower limit of detection (0.66 μM), excellent limit of quantification (2.19 μM) and good reproducibility to ZCNT 0.1 NCs as compared to others for 5-HT sensing studies.

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“…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.…”

Section: Introductionmentioning

confidence: 99%

“…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. 21 This involved an "emission-on/emission-off" system, whereby sample pH was adjusted to prevent emission from atropine, whilst recording that of scopolamine. 21 Although this initial study showed promise, it relied upon an in-depth knowledge and understanding of the relationship between the target analytes ECL signal with pH.…”

Section: Introductionmentioning

confidence: 99%

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

et al. 2020

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Rapid and continuous appearance of novel psychoactive substances (NPS) onto the global drug market has highlighted the significant requirement for new and alternative screening methodologies. Current screening protocols, primarily consisting of the colorimetric NIK® tests, are not only inadequate for NPS but they are not compatible with any matrix other than the pure drug product. Here we discuss the potential power of electrochemiluminescence (ECL) as a simple tool for drug screening. The intrinsic advantages of ECL make it an ideal candidate as an alternative analytical technique for the rapid identification of drug species, within a range of complex matrices. NPS, often contain a mixture of substances, while analysis of complex matrices can be challenging due to a number of potential interfering species present. Traditional ECL systems typically employ a single ruthenium based luminophore. This single complex 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. Multiplexed sensors utilising several different metal luminophores as well as pH controlled emission offer viable mechanisms to tackle the limited specificity associated with ECL techniques. Utilising tropane alkaloids, atropine and scopolamine as model compounds, a straightforward ECL sensor based upon a portable screen printed electrode set up, offering rapid results at minimal cost in a variety of complex matrices has been developed. The sensors portability matches that of current screening protocols but utilises less hazardous materials and removed subjectivity. Two alternative methodologies to improve the specificity offered by ECL were investigated within this study. By exploiting the relationship between pH and ECL emission the ability to differentiate between the two structurally similar species, upon a simple ruthenium based sensor, such as shown in Figure 1, is possible. The use of pH controlled ECL, allows for emission from one species to be “switched off” within a mixed sample. With knowledge of the target species pKa this methodology can be used to tailor the sensor toward a variety of species, offering improved specificity without having to alter sensor fabrication. The employment of different metal luminophores, such as iridium and osmium, can offer the possibility to increase specificity, with different selectivity offered by each luminophore. By using a combination of different metal luminophores the ability to differentiate between structurally similar species becomes possible, something currently not attainable when utilising a single luminophore system. Furthermore, the opportunity to negate previously encountered interference effects due to matrix composition becomes viable. By utilising a combination of different metal complexes we have successfully demonstrated the ability to effectively negate the interference effect from naturally occurring amino acids present in biological matrices such as human serum, a previously noted limitation for the use of ECL within biological matrices. Here we provide a strong proof-of-concept for the development of multiplexed ECL sensors, utilising several luminophores to tackle the limited specificity currently offered by ECL. By tackling this limitation, the potential applications of current ECL based sensors could be expanded significantly. Whats more our sensor design offers the ability to analyse a variety of complex biological matrices without the requirement of sample preparation. The potential to utilise one portable technique for drug screening across a variety of matrices, with the ability to tailor emission toward a specific drug species, without the requirement of a full lab facility will not only benefit the wider sensing community but such sensors offer the potential to reduce cost, increase throughput and simplify drug screening procedures in a variety of fields. Finally, a key challenge of electroanalytical sensors is multiplexed detection and this study will facilitate understanding of ECL based sensors to overcome this hurdle. Figure 1

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Tale of Two Alkaloids: pH-Controlled Electrochemiluminescence for Differentiation of Structurally Similar Compounds

Cited by 24 publications

References 54 publications

Voltammetry as a rapid screening method for NPS identification

Voltammetry as a rapid screening method for NPS identification

Structural refinement and electrochemical properties of one dimensional (ZnO NRs)1−x(CNs)x functional hybrids for serotonin sensing studies

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

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