Discrimination of opium from Afghanistan and Myanmar by infrared spectroscopy coupled with machine learning methods.

Afghanistan and Myanmar are two overwhelming opium production places. In this study, rapid and efficient methods for distinguishing opium from Afghanistan and Myanmar were developed using infrared spectroscopy (IR) coupled with multiple machine learning (ML) methods for the first time. A total of 146 authentic opium samples were analyzed by mid-IR (MIR) and near-IR (NIR), within them 116 were used for model training and 30 were used for model validation. Six ML methods, including partial least squares discriminant analysis (PLS-DA), orthogonal PLS-DA (OPLS-DA), k-nearest neighbour (KNN), support vector machine (SVM), random forest (RF), and artificial neural networks (ANNs) were constructed and compared to get the best classification effect. For MIR data, the average of precision, recall and f1-score for all classification models were 1.0. For NIR data, the average of precision, recall and f1-score for different classification models ranged from 0.90 to 0.94. The comparison results of six ML models for MIR and NIR data showed that MIR was more suitable for opium geography classification. Compared with traditional chromatography and mass spectrometry profiling methods, the advantages of MIR are simple, rapid, cost-effective, and environmentally friendly. The developed IR chemical profiling methodology may find wide application in classification of opium from Afghanistan and Myanmar, and also to differentiate them from opium originating from other opium producing countries. This study presented new insights into the application of IR and ML to rapid drug profiling analysis.

Geographical classification of opium samples from Myanmar and Afghanistan by NMR profiling and chemometrics.

This study presents a new strategy to discriminate between opium samples obtained from different geographical regions. Nuclear magnetic resonance (NMR) profiling and chemometrics were applied to geographical classification of opium originating from Myanmar and Afghanistan, which are two major opium producing countries in the world. A total of 50 Myanmar and 46 Afghanistan authentic opium samples were analyzed by 1 H-NMR, and the chemical profiles were characterized. Different sample preparation procedures, data processing methods, and chemometrics were compared to obtain the best classification effect. It was found that drying and the addition of buffer solutions were unnecessary for classification purposes; thus, the gum opium samples were extracted directly with CD3 OD, which shortened sample preparation time. A full discrimination between the two geographical origins was achieved by 1 H-NMR profiling and orthogonal partial least squares discriminant analysis. All 30 opium samples were classified correctly by the developed orthogonal partial least squares discriminant analysis model. Compared with traditional chromatography and mass spectrometry profiling methods, the 1 H-NMR profiling method was faster (with instrument analysis time of less than 3 min) and reproducible. This study provides new insights into the applying of NMR profiling and chemometrics to rapid drug profiling analysis.

Qualitative and Quantitative Analysis of Five Indoles or Indazole Amide Synthetic Cannabinoids in Suspected E-Cigarette Oil by GC-MS.

OBJECTIVES: To establish the GC-MS qualitative and quantitative analysis methods for the synthetic cannabinoids, its main matrix and additives in suspicious electronic cigarette (e-cigarette) oil samples. METHODS: The e-cigarette oil samples were analyzed by GC-MS after diluted with methanol. Synthetic cannabinoids, its main matrix and additives in e-cigarette oil samples were qualitatively analyzed by the characteristic fragment ions and retention time. The synthetic cannabinoids were quantitatively analyzed by using the selective ion monitoring mode. RESULTS: The linear range of each compound in GC-MS quantitative method was 0.025-1 mg/mL, the matrix recovery rate was 94%-103%, the intra-day precision relative standard deviations (RSD) was less than 2.5%, and inter-day precision RSD was less than 4.0%. Five indoles or indazole amide synthetic cannabinoids were detected in 25 e-cigarette samples. The main matrixes of e-cigarette samples were propylene glycol and glycerol. Additives such as N,2,3-trimethyl-2-isopropyl butanamide (WS-23), glycerol triacetate and nicotine were detected in some samples. The content range of synthetic cannabinoids in 25 e-cigarette samples was 0.05%-2.74%. CONCLUSIONS: The GC-MS method for synthesizing cannabinoid, matrix and additive in e-cigarette oil samples has good selectivity, high resolution, low detection limit, and can be used for simultaneous qualitative and quantitative analysis of multiple components; The explored fragment ion fragmentation mechanism of the electron bombardment ion source of indole or indoxamide compounds helps to identify such substances or other compounds with similar structures in cases.

New trends of new psychoactive substances (NPS)-infused chocolate: Identification and quantification of trace level of NPS in complex matrix by GC-MS and NMR.

For the first time, the identification and quantification of trace level of new psychoactive substances (NPS) in a complex chocolate matrix have been reported. Since the beginning of 2022, suspected NPS-infused chocolate samples confiscated in inbound packages have been continuously sent to our laboratory for analysis. The qualitative gas chromatography-mass spectrometry (GC-MS) results were verified by 1H nuclear magnetic resonance (1H NMR) and 19F NMR to distinguish between potential aromatic isomers. A total of 11 NPS including deoxymethoxetamine, 3-OH-PCP, 6-APB, 4-APB, 4-OH-MiPT, 3-FEA, 2-FEA, 3-MMC, bromazolam, 2-FDCK, and ADB-BUTINACA were detected in 65 seized chocolate samples. A general 1H quantitative NMR (1H qNMR) method for quantification of 297 types of NPS in complex chocolate matrixes was devised for the first time after rigorous analysis of various critical features of merit, including suitable deuterated solvent, internal standard, quantitative peaks, and instrument acquisition parameters. Validation of the method using six different types of NPS afforded limits of detection of 0.05-0.1 mg/mL, limits of quantification of 0.01-0.03 mg/mL, repeatability and reproducibility lower than 0.5% and 3.6%, recoveries of 91.7%∼104.4%, and absence of matrix effect. The quantitative analysis of 65 seized chocolate samples by 1H qNMR and 19F qNMR showed that the content of NPS was in the range of 0.5 mg/g∼44.1 mg/g. Generally, the developed qNMR method was simple, fast, precise, and can be performed without reference materials of NPS. Since the type and content of NPS are relatively random, chocolate consumers will face huge health risks. Therefore, this new trend of NPS-infused chocolate deserves and requires more attention from national NPS monitoring departments as well as forensic laboratories.

Identification and analytical characterization of N-propyl norbutylone, N-butyl norbutylone, N-benzyl norheptedrone, and N-pyrrolidinyl-3,4-DMA.

In this study, the analytical characterization of three cathinones and one N-pyrrolidinyl-substituted amphetamine derivative is described: 1-([3,4-methylenedioxyphenyl])-2-(propylamino)butan-1-one (N-propyl norbutylone 1), 1-([3,4-methylenedioxyphenyl])-2-(butylamino)butan-1-one (N-butyl norbutylone 2), 2-(benzylamino)-1-phenylheptan-1-one (N-benzyl norheptedrone 3), and 1-(1-[3,4-dimethoxyphenyl]propan-2-yl)pyrrolidine (N-pyrrolidinyl-3,4-DMA 4). The identification was based on ultra-high-performance liquid chromatography-quadrupole time-of-flight-mass spectrometry (UHPLC-QTOF-MS), gas chromatography-orbitrap MS (GC-Orbitrap-MS), nuclear magnetic resonance spectroscopy (NMR), and Fourier transform infrared (FT-IR). GC-Orbitrap-MS, with higher mass accuracy, benefit more on the accurate structure elucidation of product ions compared with the low-resolution GC-MS. The collision-induced dissociation (CID) and electron ionization (EI) pathways of these compounds were examined to assist forensic laboratories in elucidating the structure of new psychoactive substances (NPS) with similar structure in their case work. In addition, electron activated dissociation (EAD) was applied to analyze N-benzyl norheptedrone, which showed only one product ion in the CID mode. The result showed that for compound with limited product ions in the CID mode, the EAD mode can give more complementary information for structure elucidation. In addition, quantitative NMR (qNMR) was applied for the quantification of four powdered/crystal and two herbal blend seized samples. To our knowledge, no analytical data about the compounds 3 and 4 have appeared until now, making this the first report on these compounds.

The application of 19F NMR spectroscopy for the analysis of fluorinated new psychoactive substances (NPS).

In this study, fluorine-19 nuclear magnetic resonance spectroscopy (19F NMR) served as a highly specific tool for identification of fluorinated new psychoactive substances (NPS) as well as a suitable analytical method for the accurate quantification of fluorinated NPS in different seized samples. In the first part of the study, 19F NMR spectroscopy of a number of different fluorinated NPS, including 51 synthetic cannabinoids, 8 synthetic cathinones, 7 phenethylamines, 8 fentanyl analogues, and 9 other types of compounds was conducted. The chemical shifts and multiplet of the primary fluorides (RCH2F), fluorobenzenes (ortho-ArF, meta-ArF, and para-ArF), and trifluoromethylbenzenes (ArCF3) were discussed in detail to illustrate the role of 19F signals as special fingerprints in assisting the structure identification of fluorine-containing NPS. To the best of our knowledge, this study is the largest evaluation of fluorinated NPS compounds by 19F NMR. The second part of this study dealt with the problems encountered in the 19F quantification procedure and the criteria to be considered for successful quantification by 19F NMR. General high field (HF)- and low field (LF)- 19F qNMR methods for the quantification of fluorinated NPS were established after the thorough discussion of NMR spectrum acquisition and processing parameters such as: transmitter frequency offset (O1P), spin-lattice relaxation time (T1), and different baseline correction methods. The limit of quantifications (LOQs) for HF-19F qNMR varied between 0.1 mg/mL and 0.2 mg/mL, and for LF-19F qNMR varied between 1.0 mg/mL and 2.0 mg/mL. The limit of detections (LODs) for HF-19F qNMR varied between 0.03 mg/mL and 0.06 mg/mL, and for LF-19F qNMR varied between 0.3 mg/mL and 0.6 mg/mL. Finally, the developed methods were applied for the quantification of fluorinated-NPS in seventeen herbal blends, e-liquid, tablet, and powder NPS seizures.

Characterization of 17 unknown ketamine manufacturing by-product impurities by UHPLC-QTOF-MS.

This study initially reported the selection and characterization of 17 unknown impurities attributed to the manufacture process of ketamine. A total of 150 seized ketamine samples were investigated through ultra-high-performance liquid chromatography-quadrupole-time of flight (UHPLC-Q-TOF). Seventeen characteristic impurities were selected in accordance with four criteria: The compound was detected in over 10% of all 150 seized ketamine samples, the compound had at least one nitrogen, the unsaturation of the compound was more than 5, and the compound was stable in the dilution solvent solution for 48 h. The accurate masses of the protonated molecules and product ions of the target impurities were obtained based on the full scan mode and the product ion mode of Q-TOF, respectively. Lastly, the possible structures of the above impurities were tentatively elucidated in accordance with the synthetic route of ketamine, protonated molecules, and MS2 product ions. All 17 impurities had the same skeleton of deschloroketamine (DCK), but were substituted with additional chlorine, hydroxyl, methyl, cyclohexane, and o-chlorophenyl cyclopentyl ketone substituents. Under the electrospray ionization (ESI), the above impurities showed similar characteristic fragment ions through the dissociation of the CH3 NH2, C2 H6 NH, H2 O, CO, C2 H4 O, C4 H6 , and C2 H2 moieties. The above impurities have been routinely used for the profiling analysis of seized ketamine samples in the National Narcotics Laboratory of China and employed to establish the tactical intelligence for law enforcement agencies.

Identification of AD-18, 5F-MDA-19, and pentyl MDA-19 in seized materials after the class-wide ban of synthetic cannabinoids in China.

To curb the manufacturing, trafficking, and abuse of synthetic cannabinoids, China implemented a class-wide regulation on synthetic cannabinoids in July 2021. Recently, three different types of synthetic cannabinoid analogs that were not covered by the generic definitions were detected in seized powdered and e-liquid materials. These derivatives included 2-(2-(1-(4-fluorobenzyl)-1H-indol-3-yl)acetamido)-3,3-dimethylbutanamide (AD-18), N'-(1-(5-fluoropentyl)-2-oxoindolin-3-ylidene)benzohydrazide (5F-MDA-19), and N'-(2-oxo-1-pentylindolin-3-ylidene)benzohydrazide (pentyl MDA-19). Identification was based on ultra-high-performance liquid chromatography-quadrupole time-of-flight-mass spectrometry (UHPLC-QTOF-MS), gas chromatography-mass spectrometry (GC-MS), nuclear magnetic resonance spectroscopy (NMR), and Fourier transform infrared spectroscopy (FT-IR). AD-18 is a methylene analog of ADB-FUBICA. No chemical or pharmacological data about AD-18 and 5F-MDA-19 have appeared until now, making this the first report on these two compounds. Pentyl MDA-19 has previously been reported to have high affinity for cannabinoid CB1 and CB2 receptors, but this is the first report of its presence in the recreational drug market. Moreover, the collision-induced dissociation (CID) and electron ionization (EI) characteristic fragmentation routes of AD-18 and the other two MDA-19 derivatives were also discussed to facilitate forensic laboratories in their identification of other substances with a similar structure in their case work.

Structure Analysis of the Interfering Substance N-methyl-2-phenylpropan-1-amine of Methamphetamine in Wastewater.

OBJECTIVES: To analyze the chemical structure of the interfering substance that affects the result of methamphetamine analysis in wastewater. METHODS: A combination of GC-MS and liquid chromatography-quadrupole time-of-flight mass spectrometry (LC-QTOF-MS) was used to analyze the mass spectrum characteristics of the interfering substance that affects the result of methamphetamine analysis and to infer its possible structure. Liquid chromatography-triple quadrupole-mass spectrometry (LC-TQ-MS) was used to confirm the control material. RESULTS: Using LC-QTOF-MS in positive electrospray ionization (ESI+) mode, the mass-to-charge ratio (m/z) of quasi-molecular ion in the MS1 mass spectrometry of interfering substance was identical to that of methamphetamine, indicating that the interfering substance was probably an isomer of methamphetamine. The MS2 mass spectra obtained at three collision energies of 15 V, 30 V and 45 V were highly similar to methamphetamine, suggesting that the interfering substance contained methylamino and benzyl groups. Further analysis using GC-MS in electron impact (EI) ionization mode showed that the base peak in the mass spectrum of the interfering substance was at m/z 44. The interfering substance was confirmed to be N-methyl-2-phenylpropan-1-amine by compared with the standard reference. CONCLUSIONS: The chemical structure of N-methyl-2-phenylpropan-1-amine is highly similar to methamphetamine, which is easy to cause interference for the detection of trace amounts of methamphetamine in wastewater using LC-TQ-MS. Therefore, in the actual analysis, the chromatographic retention time can be used to distinguish between N-methyl-2-phenylpropan-1-amine and methamphetamine.

Identification and quantification of 10 indole/indazole carboxamide synthetic cannabinoids in 36 herbal blends by gas chromatography-mass spectrometry and nuclear magnetic resonance spectroscopy.

Herbal blends containing synthetic cannabinoids have become popular alternatives to marijuana. The number of synthetic cannabinoids and speed of their emergence enable this group of compounds particularly challenging in terms of detection, monitoring, and responding. In this work, both gas chromatography-mass spectrometry (GC-MS) and nuclear magnetic resonance spectroscopy (NMR) methods were developed for the identification and quantification of synthetic cannabinoids in herbal blends. Ten types of indole/indazole carboxamide synthetic cannabinoids, which showed different types of substitutions connected to nitrogen of the indole/indazole carboxamide, were detected in 36 herbal blends. The GC-MS fragmentation routes of indole/indazole carboxamide synthetic cannabinoids were discussed in detail for structure identification purpose. The concentration range of synthetic cannabinoid in 36 herbal blends was 1.9-50.6 mg/g using GC-MS method, while 1.5-49.0 mg/g by NMR method. Nicotine in herbal blends was quantified by NMR method without using reference material, and showed a variation of 5.3-44.7 mg/g. For quantitative analysis, NMR method showed great advantage in the absence of reference material, while GC-MS method showed great merit for multiple-compound analysis when reference material was available. Therefore, for the quantitative analysis of new emerged synthetic cannabinoid in herbal blends, different methods could be chosen by considering whether reference material is available, as well as the number and types of synthetic cannabinoids detected in a single sample.

Discrimination of phenethylamine regioisomers and structural analogues by Raman spectroscopy.

In this study, the Raman spectra of 21 phenethylamines were obtained using far-red excitation (785 nm). The distinguishing ability of Raman for phenethylamines, especially for phenethylamine regioisomers and structural analogues, was investigated. Here, the evaluation of a cross section of Raman spectra demonstrated that all types of phenethylamines were distinguishable, even for certain structural analogues with high spectrum similarity. Raman exhibited high distinguishing ability for phenethylamine regioisomers that differ in the substitution position of halogen, methoxy, alkyl, or other substituted groups; as well as for structural analogues containing different groups, such as furanyl, 2,3-dihydrofuranyl, halogen, and alkyl substituted at the same position. The Raman spectra for homologues with differences in only a methyl group were found to be highly similar; however, their spectra demonstrated small but detectable differences. Four analogue mixtures and 59 seized samples were also analyzed to study the practical use of the Raman method in forensic field. 95% of the seized samples were correctly identified, which significantly validated the ability of Raman method in identifying the correct isomers. Accordingly, this study provides a non-destructive, high-throughput and minimal sample preparation technique for the discrimination of phenethylamines.

New qualitative analysis strategy for illicit drugs using Raman spectroscopy and characteristic peaks method.

Performing fast qualitative identification of seized illegal drugs by Raman spectroscopy is challenging due to fluorescence interference as well as chemical complexity. Spectrometers with 785-nm excitation, 1,064-nm excitation, and sequentially shifted excitation (SSE) were compared for their effect on fluorescence reduction. The characteristic peaks method, which is independent of cutting agents, was tested as a new strategy to broaden the application of the Raman technique. The suitability of the characteristic peaks method was fully examined by analyzing a large amount of seized illegal drugs, including 72 methamphetamine hydrochloride (concentration range of 13.9%-99.4%), 68 ketamine hydrochloride (17.7%-99.8%), 176 heroin hydrochloride (5.2%-79.5%), 51 cocaine hydrochloride (21.1%-94.5%), and 33 cocaine base (30.9%-92.5%) samples. The results showed that seized methamphetamine, ketamine, and cocaine samples had no or little fluorescence. Hence, in regard to detection of these samples, the advantage of using 1,064-nm excitation and SSE compared with 785-nm excitation was quite limited. Regarding the heroin samples, a significant improvement of the "high" confident positive detected rate was evident for 1,064 nm excitation (60.8%) and SSE (61.4%), compared with 785-nm excitation (13.1%). However, it was also seen that even if 1,064-nm excitation and SSE were applied, the fluorescence of heroin samples was still unable to be fully overcome. By using the characteristic peaks method, low LOD results of 5%-20% were acquired for 40 types of drug mixtures, and lower LODs were obtained for the 60% of the drug mixtures compared with library searching method. Raman spectroscopy in conjunction with the characteristic peaks method was shown to be fast, simple, accurate, and sensitive in the qualitative analysis of seized drug samples.

[Distribution Characteristics of Drugs of Abuse and Their Metabolites in Aqueous Environment of Beijing, China].

This work investigated the occurrence and distribution of six drugs of abuse and their metabolites, i.e. methamphetamine(METH), amphetamine(AMP), ketamine(KET), ephedrine(EPH), methcathinone(MC) and hydroxylimine(HY) in the surface water and groundwater in Beijing, China. Forty-three samples were collected and analyzed by solid-phase extraction and high performance liquid chromatography coupled to tandem mass spectrometry(SPE-HPLC-MS/MS). The result showed that KET, MC and HY were not detected in any of the analyzed samples. EPH was the most abundant and ubiquitous compound in the surface water, with the detection frequency of 42% and average concentration of 10.1 ng·L-1, followed by METH(25%, average 1.8 ng·L-1). Only trace amount of AMP was detected in some groundwater samples(n.d.-2.2 ng·L-1), with detection frequency of 21%. Spatial variation of target drug concentrations in the aqueous environment was also studied, and the highest levels of METH and EPH were observed in Liangshui River. Risk assessment suggested that the RQ values of target compounds were lower than 0.10. Although no toxic effects could be expected at the current levels, further studies are needed to assess the long-term effect of drugs of abuse and their metabolites on organisms as well as the joint toxic effect.