Identification of Different Forms of Cocaine and Substances Used in Adulteration Using Near‐infrared Raman Spectroscopy and Infrared Absorption Spectroscopy

Identification of cocaine and subsequent quantification immediately after seizure are problems for the police in developing countries such as Brazil. This work proposes a comparison between the Raman and FT‐IR techniques as methods to identify cocaine, the adulterants used to increase volume, and possible degradation products in samples seized by the police. Near‐infrared Raman spectra (785 nm excitation, 10 sec exposure time) and FT‐IR‐ATR spectra were obtained from different samples of street cocaine and some substances commonly used as adulterants. Freebase powder, hydrochloride powder, and crack rock can be distinguished by both Raman and FT‐IR spectroscopies, revealing differences in their chemical structure. Most of the samples showed characteristic peaks of degradation products such as benzoylecgonine and benzoic acid, and some presented evidence of adulteration with aluminum sulfate and sodium carbonate. Raman spectroscopy is better than FT‐IR for identifying benzoic acid and inorganic adulterants in cocaine.     

The Discrimination of Colored Acrylic,Cotton, and Wool Textile Fibers Using Micro‐Raman Spectroscopy. Part 1: In situ Detection and Characterization of Dyes

Raman spectroscopy has been applied to characterize fiber dyes and determine the discriminating ability of the method. Black, blue, and red acrylic, cotton, and wool samples were analyzed. Four excitation sources were used to obtain complementary responses in the case of fluorescent samples. Fibers that did not provide informative spectra using a given laser were usually detected using another wavelength. For any colored acrylic, the 633‐nm laser did not provide Raman information. The 514‐nm laser provided the highest discrimination for blue and black cotton, but half of the blue cottons produced noninformative spectra. The 830‐nm laser exhibited the highest discrimination for red cotton. Both visible lasers provided the highest discrimination for black and blue wool, and NIR lasers produced remarkable separation for red and black wool. This study shows that the discriminating ability of Raman spectroscopy depends on the fiber type, color, and the laser wavelength.     

Evaluation and classification of fentanyl-related compounds using EC-SERS and machine learning

Multiple analytical techniques for the screening of fentanyl-related compounds exist. High discriminatory methods such as GC–MS and LC–MS are expensive, time-consuming, and less amenable to onsite analysis. Raman spectroscopy provides a rapid, inexpensive alternative. Raman variants such as electrochemical surface-enhanced Raman scattering (EC-SERS) can provide signal enhancements with 10¹⁰ magnitudes, allowing for the detection of low-concentration analytes, otherwise undetected using conventional Raman. Library search algorithms embedded in instruments utilizing SERS may suffer from accuracy when multicomponent mixtures involving fentanyl derivatives are analyzed. The complexing of machine learning techniques to Raman spectra demonstrates an improvement in the discrimination of drugs even when present in multicomponent mixtures of various ratios. Additionally, these algorithms are capable of identifying spectral features difficult to detect by manual comparisons. Therefore, the goal of this study was to evaluate fentanyl-related compounds and other drugs of abuse using EC-SERS and to process the acquired data using machine learning—convolutional neural networks (CNN). The CNN was created using Keras v 2.4.0 with Tensorflow v 2.9.1 backend. In-house binary mixtures and authentic adjudicated case samples were used to evaluate the created machine-learning models. The overall accuracy of the model was 98.4 ± 0.1% after 10-fold cross-validation. The correct identification for the in-house binary mixtures was 92%, while the authentic case samples were 85%. The high accuracies achieved in this study demonstrate the advantage of using machine learning to process spectral data when screening seized drug materials comprised of multiple components.     

莫达非尼药片的激光共聚焦显微拉曼光谱快速检验

目的建立莫达非尼药片的拉曼光谱快速定性检验方法。方法莫达非尼对照品和药片检材分别研磨后经拉曼光谱检验得到拉曼谱图。结果经比较,二者图谱一致,确定检出莫达非尼成分,结果可靠。结论莫达非尼药片在本文所述的条件下有较好的响应,峰型较好,峰位准确,同时药片中的淀粉等物质干扰较小。本文所建立的拉曼光谱检验方法,简便、高效、准确,可供一线执法、检验部门对查获的莫达非尼药片进行快速的定性检验。     

Screening tablets for DOB using surface-enhanced Raman spectroscopy

2,5,-Dimethoxy-4-bromoamphetamine (DOB) is of particular interest among the various "ecstasy" variants because there is an unusually long delay between consumption and effect, which dramatically increases the danger of accidental overdose in users. Screening for DOB in tablets is problematic because it is pharmacologically active at 0.2-3 mg, which is c. 50 times less than 3,4-methylenedioxy-N-methylamphetamine (MDMA) and makes it more difficult to detect in seized tablets using conventional spot tests. The normal Raman spectra of seized DOB tablets are dominated by the bands of the excipient with no evidence of the drug component. Here we report the first use of on-tablet surface-enhanced Raman spectroscopy (SERS) to enhance the signal from a low concentration drug. Raman studies (785-nm excitation) were carried on series of model DOB/lactose tablets (total mass c. 400 mg) containing between 1 mg and 15 microg of DOB and on seized DOB tablets. To generate surface-enhanced spectra, 5 microL of centrifuged silver colloid was dispensed onto the upper surface of the tablets, followed by 5 microL of 1.0 mol/dm(3) NaCl. The probe laser was directed onto the treated area and spectra accumulated for c. 20 sec (10 sec x 2). It was found that the enhancement of the DOB component in the model tablets containing 1 mg DOB/tablet and in the seized tablets tested was so large that their spectra were completely dominated by the vibrational bands of DOB with little or no contribution from the unenhanced lactose excipient. Indeed, the most intense DOB band was visible even in tablets containing just 15 microg of the drug. On-tablet surface-enhanced Raman spectroscopy is a simple method to distinguish between low dose DOB tablets and those with no active constituent. The fact that unique spectra are obtained allows identification of the drug while the lack of sample preparation and short signal accumulation times mean that the entire test can be carried out in <1 min.     

GC-MS and GC-IRD analysis of 2-, 3- and 4-methylmethamphetamine and 2-, 3- and 4-methylamphetamine

4-Methylmethamphetamine has been detected in samples submitted for analysis in several states throughout Australia. Six ring substituted methyl isomers of methamphetamine and amphetamine were synthesised and analysed. As the regioisomeric 2-, 3- and 4-methylmethamphetamine and 2-, 3- and 4-methylamphetamine have virtually identical mass spectra, the use of MS is an ineffective technique to discriminate between these closely related compounds. We set out to determine whether the regioisomers could be differentiated by a combination of GC-MS, acetyl derivatisation and GC-IRD. We demonstrate that the three isomers of methylmethamphetamine and methylamphetamine can be separated by GC, and a combination of acetyl derivatisation and vapour phase IR can identify the specific ring substituted compound.     

A real-time PCR assay for the relative quantification of the tetrahydrocannabinolic acid (THCA) synthase gene in herbal Cannabis samples

In this study, we wanted to investigate whether or not the tetrahydrocannabinolic acid (THCA) synthase gene, which codes for the enzyme involved in the biosynthesis of THCA, influences the production and storage of tetrahydrocannabinol (THC) in a dose-dependent manner. THCA is actually decarboxylated to produce THC, the main psychoactive component in the Cannabis plant. Assuming as the research hypothesis a correlation between the gene copy number and the production of THC, gene quantification could be useful in forensics in order to complement or replace chemical analysis for the identification and classification of seized Cannabis samples, thus distinguishing the drug-type from the fibre-type varieties. A real-time PCR assay for the relative quantification of the THCA synthase gene was then validated on Cannabis samples; some were seized from the illegal drug market and others were derived from experimental cultivation. In order to determine the gene copy number to compare high vs. low potency plants, we chose the ΔΔCt method for TaqMan reactions. The assay enabled single plants with zero, one, and two copies of the gene to be distinguished. As a result of this first part of the research on the THCA synthase gene (the second part will cover a study of gene expression), we found no correlation between THCA synthase gene copy number and the content of THC in the herbal Cannabis samples tested.     

Characterization of Blue Pigments Used in Automotive Paints by Raman Spectroscopy

Micro‐Raman spectroscopy was applied to forensic identification of pigments in paint chips and provided differentiation between paint samples. Sixty‐six blue automotive paint samples, 26 solid and 40 metallic were examined. It was found that the majority of the collected Raman spectra provided information about the pigments present. However, in some cases, fluorescence precluded pigment identification. Using laser excitation at longer wavelengths or pretreatment to effect photobleaching often resulted in reduced fluorescence, particularly for solid color samples, and allowed pigment identification. The examined samples were compared pairwise taking into account number, location, and intensity of absorption bands in their infrared spectra. The estimated discrimination power ranged from 97% for solid paint samples to 99% for metallic paint samples.     

Synthesis and Analysis of Glucuronic Acid‐Conjugated Metabolites of 4‐Bromo‐2,5‐Dimethoxyphenethylamine

In the study reported here, two glucuronic acid‐conjugated metabolites of 4‐bromo‐2,5‐dimethoxyphenethylamine (2C‐B)—a ring‐substituted psychoactive phenethylamine—were chemically synthesized for the first time and a method for analyzing them in urine was developed. β‐D‐Glucuronide of 4‐bromo‐2,5‐dimethoxyphenylethylalcohol was successfully synthesized using methyl 2,3,4‐tri‐Ο‐acetyl‐1‐O‐(trichloroacetimidoyl)‐α‐D‐glucuronate as a glucuronyl donor and boron trifluoride diethylether complex as a Lewis acid catalyst. β‐D‐Glucuronide of 4‐bromo‐2,5‐dimethoxyphenylacetic acid was synthesized by condensing 4‐bromo‐2,5‐dimethoxyphenylacetic acid and benzyl D‐glucuronate followed by benzyl group deprotection based on catalytic hydrogenation. Two glucuronic acid‐conjugated metabolites of 2C‐B in urine were qualitatively and semiquantitatively evaluated via direct liquid chromatography/mass spectrometry (LC/MS) analysis of a diluted urine sample. The simple method proposed is expected to be useful for studying the metabolic fate of 2C‐B.     

Detection of Acetone Processing of Castor Bean Mash for Forensic Investigation of Ricin Preparation Methods*

Abstract: Samples containing the toxic castor bean protein ricin have been recently seized in connection with biocriminal activity. Analytical methods that enable investigators to determine how the samples were prepared and to match seized samples to potential source materials are needed. One commonly described crude ricin preparation method is acetone extraction of crushed castor beans. Here, we describe the use of solid‐phase microextraction and headspace analysis to determine whether castor beans were processed by acetone extraction. We prepared acetone‐extracted castor bean mash, along with controls of unextracted mash and mash extracted with nonacetone organic solvents. Samples of acetone‐extracted mash and unextracted mash were stored in closed containers for up to 109 days at both room temperature and ?20°C, and in open containers at room temperature for up to 94 days. Acetone‐extracted bean mash could consistently be statistically distinguished from controls, even after storage in open containers for 94 days.     

The Analysis of Colored Acrylic,Cotton, and Wool Textile Fibers Using Micro‐Raman Spectroscopy. Part 2: Comparison with the Traditional Methods of Fiber Examination

In the second part of this survey, the ability of micro‐Raman spectroscopy to discriminate 180 fiber samples of blue, black, and red cottons, wools, and acrylics was compared to that gathered with the traditional methods for the examination of textile fibers in a forensic context (including light microscopy methods, UV‐vis microspectrophotometry and thin‐layer chromatography). This study shows that the Raman technique plays a complementary and useful role to obtain further discriminations after the application of light microscopy methods and UV‐vis microspectrophotometry and assure the nondestructive nature of the analytical sequence. These additional discriminations were observed despite the lower discriminating powers of Raman data considered individually, compared to those of light microscopy and UV‐vis MSP. This study also confirms that an instrument equipped with several laser lines is necessary for an efficient use as applied to the examination of textile fibers in a forensic setting.     

The analysis of substituted cathinones. Part 1: chemical analysis of 2-, 3- and 4-methylmethcathinone

The ring substituted methyl isomers of methcathinone, 2-, 3- and 4-methylmethcathinone were analysed. The 2- and 3-isomers were synthesized. The 4-methylmethcathinone isomer is also known as mephedrone and has been widely studied. We present GCMS, NMR and IR data for the three isomers. We show that the three isomers can be separated by GCMS and that the IR spectra for the three compounds can be used to distinguish between them. A seized sample was analysed and it was found to contain 4-methylmethcathinone and benzocaine.     

Experimental Study on the Postmortem Redistribution of the Substituted Phenethylamine, 25B‐NBOMe

2‐(4‐Bromo‐2,5‐dimethoxyphenyl)‐N‐(2‐methoxybenzyl)ethanamine (25B‐NBOMe) is a substituted phenethylamine, which has become highly prevalent worldwide since 2014. Recently, in an autopsy case involving fatal 25B‐NBOMe intoxication, we found the postmortem increase of 25B‐NBOMe concentration in the cardiac blood approximately 2 days after death. The aim of this study was to investigate the distribution of 25B‐NBOMe and reproduce the postmortem redistribution using a rat model. Sprague‐Dawley rats were killed 30 min after intraperitoneal injection of 25B‐NBOMe (0.5 mg/kg) and left for 0, 3, 6, 9, 15, or 24 h (six rats at each time point). Postmortem 25B‐NBOMe concentrations in the cardiac blood increased by more than 10‐fold at 6‐h postmortem. 25B‐NBOMe accumulated primarily in the lung. Moreover, this postmortem redistribution occurred even in rats that had died 1 week following the 25B‐NBOMe administration. These findings indicate that attention should be paid to sample collection and data interpretation in the toxicological analysis of 25B‐NBOMe.     

红外光谱法用于安钠咖中咖啡因和苯甲酸钠快速定性和定量分析

目的 建立安钠咖样品中咖啡因和苯甲酸钠快速定性和定量分析的红外光谱方法.方法 采用高纯度咖啡因和苯甲酸钠混合制样的方法制备定性和定量建模样品,通过分析混合样品的红外光谱图,确定安钠咖样品中咖啡因和苯甲酸钠的特征吸收峰.采用偏最小二乘法(partial least squares,PLS)建立红外光谱定量模型.结果 通过...     

Comparison and classification of methamphetamine seized in Japan and Thailand using gas chromatography with liquid-liquid extraction and solid-phase microextraction

Methamphetamine (MA) is one of the most frequently abused drugs worldwide. The aim of this study is to improve the analytical method for profiling MA impurity in order to compare and classify MA crystals seized in different countries and to investigate the relationships between seizures. To compare MA samples seized in Japan and Thailand, the following analytical method was adopted. A 50mg sample of MA.HCl was dissolved in 1ml of buffer solution (four parts 0.1M phosphate buffer, pH 7.0, and one part 10% Na(2)CO(3)), impurities were extracted with 0.5ml of ethyl acetate containing four internal standards (n-decane, n-pentadecane, n-eicosane and n-octacosane) and analyzed by gas chromatography with a flame ionization detector on a DB-5 capillary column (0.32mm i.d.x30m, film thickness 1.0mum). Fourteen characteristic peaks on chromatograms were selected for the comparison and classification of samples, and the data were evaluated by the Euclidean distance of the relative peak areas after logarithmic transformation. Sixty-nine samples seized in Japan and 42 seized in Thailand were analyzed. The samples were classified into four groups roughly by cluster analysis. In addition, when it was difficult to compare samples that had fewer impurities on chromatograms obtained from liquid-liquid extraction (LLE), solid-phase microextraction (SPME) was effective. Because many characteristic peaks were detected using SPME, SPME made it easy to compare samples of high purity. The combination of LLE and SPME was useful for impurity profiling of MA samples seized in different countries.     

Surface-enhanced Raman spectroscopy for trace identification of controlled substances: Morphine, codeine, and hydrocodone

We obtain the normal Raman and surface-enhanced Raman spectrum of three controlled substances: morphine, codeine, and hydrocodone. The spectra are assigned with the aid of density functional theory. Because of rather intense fluorescence, normal Raman spectra suffer from poor signal-to-noise, even when differential subtraction techniques are employed. On the other hand, surface enhancement by Ag nanoparticles both enhances the Raman signal and suppresses the fluorescence, enabling far more sensitive detection and identification. We also present a set of discriminant bands, useful for distinguishing the three compounds, despite the similarities in their structures.     

Raman Spectroscopy as a Simple,Rapid, Nondestructive Screening Test for Methamphetamine in Clandestine Laboratory Liquids

Raman spectroscopy has found increased use in the forensic controlled substances laboratory in recent years due to its rapid and nondestructive analysis capabilities. Here, Raman spectroscopy as a screening test for methamphetamine in clandestine laboratory liquid samples is discussed as a way to improve the efficiency of a laboratory by identifying the most probative samples for further workup among multiple samples submitted for analysis. Solutions of methamphetamine in ethanol, diethyl ether, and Coleman fuel were prepared in concentrations ranging from 0.5% to 10% w/v, and Raman spectra of each were collected. A concentration‐dependant Raman peak was observed at 1003 per cm in each solution in 4% w/v and greater solutions. Case samples were analyzed and also found to reliably contain this diagnostic peak when methamphetamine was present. The use of this diagnostic indicator can save the forensic controlled substances laboratory time and materials when analyzing clandestine laboratory liquid submissions.     

Quantification of the amphetamine content in seized street samples by Raman spectroscopy

A Raman spectroscopy method for determining the drug content of street samples of amphetamine was developed by dissolving samples in an acidic solution containing an internal standard (sodium dihydrogen phosphate). The Raman spectra of the samples were measured with a CDD-Raman spectrometer. Two Raman quantification methods were used: (1) relative peak heights of characteristic signals of the amphetamine and the internal standard; and (2) multivariate calibration by partial least squares (PLS) based on second derivative of the spectra. For the determination of the peak height ratio, the spectra were baseline corrected and the peak height ratio (h(amphetamine at 994 cm(-1) )/h(internal standard at 880 cm(-1) )) was calculated. For the PLS analysis, the wave number interval of 1300-630 cm(-1) (348 data points) was chosen. No manual baseline correction was performed, but the spectra were differentiated twice to obtain their second derivatives, which were further analyzed. The Raman results were well in line with validated reference LC results when the Raman samples were analyzed within 2 h after dissolution. The present results clearly show that Raman spectroscopy is a good tool for rapid (acquisition time 1 min) and accurate quantitative analysis of street samples that contain illicit drugs and unknown adulterants and impurities.     

Stable Isotope Ratios of Marijuana. I. Carbon and Nitrogen Stable Isotopes Describe Growth Conditions*

Abstract: There remains significant uncertainty in illicit marijuana cultivation. We analyzed the δ¹³C and δ¹⁵N of 508 domestic samples from known U.S.A. counties, 31 seized from a single location, 5 samples grown in Mexico and Colombia, and 10 northwest border seizures. For a subset, inflorescences and leaves were analyzed separately. These data revealed a strong correspondence, with inflorescences having slightly higher δ¹³C and δ¹⁵N values than leaves. A framework for interpreting these results is introduced and evaluated. Samples identified as outdoor‐grown by δ¹³C were generally recorded as such by the Drug Enforcement Administration (DEA). DEA‐classified indoor‐grown samples had the most negative δ¹³C values, consistent with indoor cultivation, although many were also in the outdoor‐grown domain. δ¹⁵N indicated a wide range of fertilizers across the dataset. Samples seized at the single location suggested multiple sources. Northwest border δ¹³C values suggested indoor growth, whereas for the Mexican and Colombian samples they indicated outdoor growth.     

Novel O‐propyl,S‐propyl,and N‐propyl substituted 1,4‐naphthoquinones and 1,4‐anthraquinones as potential fingermark development reagents for porous surfaces

Lawsone is a 2‐substituted‐1,4‐naphthoquinone derivative, which has been proposed as an alternative to the reagents currently used for fingermark detection on porous surfaces. 2‐substituted‐anthraquinones, which contain an additional conjugated benzene ring, have a similar chemical structure to that of lawsone. In this study, a new series of 2‐substituted‐1,4‐naphthoquinones and 2‐substituted‐1,4‐anthraquinones were synthesized and completely characterized by¹H NMR,¹³C NMR, IR, and HPLC‐TOF/MS analyses. All newly synthesized 2‐substituted‐1,4‐quinones were investigated for their ability to develop latent fingermarks on porous surfaces, and this ability was compared with that of lawsone. Each fingermark developed was graded using an established method; thus, quantitative data were attributed to each fingermark. It has been demonstrated that the 1,4 ‐ quinones react with amino acids present in latent fingermarks on selected paper surfaces to produce faint yellow‐orange impressions, which exhibit strong photoluminescence when illuminated with a forensic light source at 440 nm and observed through a red filter. None of the compounds caused background darkening. The results obtained were generally similar to those of lawsone, however, 8‐dibromo‐2‐(propylamino)naphthalene‐1,4‐dione and 5,8‐dibromo‐2‐(propylthio)naphthalene‐1,4‐dione yielded better results for copier paper and colored (blue) copier paper used in this analysis. To the best of our knowledge, this is the first study to examine the role of 1,4‐anthraquinone derivatives as potential fingermark development reagents. The results indicate that 1,4‐quinones have a potential to be used as reagents for enhancement of latent fingermarks.