Identification of closely related new psychoactive substances (NPS) using solid deposition gas-chromatography infra-red detection (GC–IRD) spectroscopy

Lee, Hui Zhi Shirley; Koh, Hui Boon; Tan, Seck Guan; Goh, Ben Justin; Lim, Rachael; Lim, Jong Lee Wendy; Yap, Tiong Whei Angeline

doi:10.1016/j.forsciint.2019.03.025

Cited by 20 publications

(17 citation statements)

References 31 publications

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“…The use of GC-FTIR as an effective tool for forensic drug identification has been already demonstrated 30 years ago, in terms of specificity needed to differentiate between closely related isomers, including cocaine/pseudococaine, phentermine/metamphetamine (Kempfert, 1988). In contrast to data afforded by widespread MS detection, the uniqueness of IR spectra allows to quickly discriminate between isomers other than optical isomers without the need for preliminary purification/derivatization, as proven for a number of different drug categories, including cannabinoids (Smith et al, 2014(Smith et al, , 2018Belal et al, 2018;DeRuiter et al, 2018;Lee et al, 2019). Since the disclosure of their existence in herbal mixtures (Auwarter et al, 2009), N-alkyl indole-3-carbonyl derivatives targeting cannabinoid receptors have been largely abused, and have accounted for a major portion of new psychoactive substances put illegally on the market.…”

Section: Resultsmentioning

confidence: 99%

“…Since their appearance in the illicit drug market, the number of new psychoactive substances (NPS) is growing at an alarming fast rate; as a consequence, the task of analysis and identification of NPS is posing a big challenge for forensic scientists on one side, and regulatory bodies, for the design and delivery of effective evidence-based responses to drug problems (Zuba, 2014;Lee et al, 2019).…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Gas Chromatography—Fourier Transform Infrared Spectroscopy for Unambiguous Determination of Illicit Drugs: A Proof of Concept

Salerno

Donato

Frison³

et al. 2020

Front. Chem.

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Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Gas Chromatography—Fourier Transform Infrared Spectroscopy for Unambiguous Determination of Illicit Drugs: A Proof of Concept

Salerno

Donato

Frison³

et al. 2020

Front. Chem.

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“…FTIR has the advantage of providing information about the chemical structure of molecules, including synthetic cathinones (Bunaciu et al, 2010; Schram et al, 2021). The detection through IR spectroscopy can generate unique spectral patterns for each compounds, the fingerprint region in the spectra, which can facilitate the differentiation between closely related drugs (Shirley Lee et al, 2019). Moreover, FTIR‐based methods require minimal to no sample preparation, can be nondestructive, and provide highly sensitive analyses (Bunaciu & Aboul‐Enein, 2021), reaching proper signal‐to‐noise ratios (Pereira et al, 2017).…”

Section: Ir and Raman Spectroscopiesmentioning

confidence: 99%

“…In addition to traditional GC and LC techniques, there are other modern techniques reported in the literature for the analysis of synthetic cathinones. GC‐IR is a technique with combined analytical advantages of GC separation and IR detection (H. Z. S. Lee et al, 2020;Shirley Lee et al, 2019; UNODC, 2020b). This is a powerful analytical platform for the differentiation between isomers (Shirley Lee et al, 2019; UNODC, 2020b).…”

Section: Emerging Techniquesmentioning

confidence: 99%

Identification of synthetic cathinones in seized materials: A review of analytical strategies applied in forensic chemistry

Campos

Krotulski

Martinis

et al. 2022

WIREs Forensic Science

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Synthetic cathinones are a class of novel psychoactive substances, commonly tested in seized materials by forensic chemistry laboratories. These drugs have been found in different types of seized materials including powders, tablets, liquids, herbs, and blotters. A comprehensive review of the literature shows that the analyses of synthetic cathinones have been performed by a diverse repertoire of techniques, from more traditional to emerging methods. Techniques commonly used in the analysis of "traditional" illicit drugs, such as color and microcrystalline tests, chromatography, capillary electrophoresis, mass spectrometry (MS), and infrared (IR), and Raman spectroscopies, have been used for screening and/or confirmatory purposes, depending on the technique and laboratories preference. However, other emerging techniques, such as nuclear magnetic resonance, high-resolution MS, direct analysis in real-time MS, gas chromatography with IR detection, and so on, have been drawing the attention of forensic scientists due to the advantages of these techniques in providing important structural data. It is important to consider that each technique presents analytical benefits and limitations, which should be considered when analyzing synthetic cathinones in seized materials. Furthermore, the combination of more than one analytical technique is always recommended, especially when an unknown synthetic cathinone is suspected and/or encountered in the sample.

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“…Many different approaches have been investigated for improving the ease with which forensic experts can confidently differentiate positional ring isomers. Some recent successful approaches include GC-IRD, 3 GC-VUV, 4 − 6 UPLC, 7 product ion spectrometry, 8 and infrared ion spectroscopy. 9 Since GC-MS is so commonly utilized in the testing of novel psychoactive substances in forensic laboratories, the analysis of these data has been improved using chemometric analysis as a means of enhancing the technique’s isomeric differentiation capabilities.…”

Section: Introductionmentioning

confidence: 99%

Utilization of Machine Learning for the Differentiation of Positional NPS Isomers with Direct Analysis in Real Time Mass Spectrometry

Bonetti

Samanipour

Asten³

2022

Anal. Chem.

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The differentiation of positional isomers is a well established analytical challenge for forensic laboratories. As more novel psychoactive substances (NPSs) are introduced to the illicit drug market, robust yet efficient methods of isomer identification are needed. Although current literature suggests that Direct Analysis in Real Time–Time-of-Flight mass spectrometry (DART-ToF) with in-source collision induced dissociation (is-CID) can be used to differentiate positional isomers, it is currently unclear whether this capability extends to positional isomers whose only structural difference is the precise location of a single substitution on an aromatic ring. The aim of this work was to determine whether chemometric analysis of DART-ToF data could offer forensic laboratories an alternative rapid and robust method of differentiating NPS positional ring isomers. To test the feasibility of this technique, three positional isomer sets (fluoroamphetamine, fluoromethamphetamine, and methylmethcathinone) were analyzed. Using a linear rail for consistent sample introduction, the three isomers of each type were analyzed 96 times over an eight-week timespan. The classification methods investigated included a univariate approach, the Welch t test at each included ion; a multivariate approach, linear discriminant analysis; and a machine learning approach, the Random Forest classifier. For each method, multiple validation techniques were used including restricting the classifier to data that was only generated on one day. Of these classification methods, the Random Forest algorithm was ultimately the most accurate and robust, consistently achieving out-of-bag error rates below 5%. At an inconclusive rate of approximately 5%, a success rate of 100% was obtained for isomer identification when applied to a randomly selected test set. The model was further tested with data acquired as a part of a different batch. The highest classification success rate was 93.9%, and error rates under 5% were consistently achieved.

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Identification of closely related new psychoactive substances (NPS) using solid deposition gas-chromatography infra-red detection (GC–IRD) spectroscopy

Cited by 20 publications

References 31 publications

Gas Chromatography—Fourier Transform Infrared Spectroscopy for Unambiguous Determination of Illicit Drugs: A Proof of Concept

Gas Chromatography—Fourier Transform Infrared Spectroscopy for Unambiguous Determination of Illicit Drugs: A Proof of Concept

Identification of synthetic cathinones in seized materials: A review of analytical strategies applied in forensic chemistry

Utilization of Machine Learning for the Differentiation of Positional NPS Isomers with Direct Analysis in Real Time Mass Spectrometry

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