Chemical profiling: A tool to decipher the structure and organisation of illicit drug markets

A systematic approach to the analysis of illicit drugs for DNA with an overview of the problems encountered

Due to the restricted nature of illicit drugs, it is difficult to conduct research surrounding the analysis of this drug material for any potential DNA in sufficient quantities acceptable for high numbers of replicates. Therefore, the current research available in peer reviewed journals thus far regarding analysing illicit drugs for DNA has been performed under varying experimental conditions, often using surrogate chemicals in place of illicit drugs. The data presented within this study originated from the analysis of genuine illicit drugs prepared both in controlled environments and those seized at the Australian border (and therefore from an uncontrolled environment) to determine if DNA can be obtained from this type of material. This study has been separated into three main parts (total n=114 samples): firstly, methamphetamine synthesised within a controlled environment was spiked with both saliva and trace DNA to determine the yield following DNA extraction; secondly, methamphetamine also synthesised in a controlled environment but on a larger scale was tested for the amount of DNA added incidentally throughout the synthesis, including the additional steps of recrystallising, homogenising and "cutting" the drug material to simulate preparation for distribution; and thirdly, the detection of human DNA within samples of cocaine and heroin seized at the Australian border. The DNA Fast Flow Microcon Device was utilised to concentrate all replicates from the same source into one combined extract to improve the DNA profiles for the samples where no DNA spiking occurred. Full STR profiles were successfully obtained from drug samples spiked with both saliva and trace DNA. Methamphetamine was present in the final DNA extracts and caused incompatibilities with the quantification of DNA using Qubit. The yields of DNA from drugs not spiked with DNA sources were much lower, resulting in 36 % of samples yielding alleles where all others did not. These results were not unexpected given these were realistic drug samples where the history of the drug material was unknown. This is the first study to obtain DNA profiles from genuine illicit drug material in both controlled and uncontrolled environments and indicates that the analysis of illicit drugs for DNA is an avenue worth pursuing to provide information which can in turn assist with disrupting the supply of these drugs. Given that DNA profiling is carried out worldwide using essentially the same systems as described within this study, the potential for impact is on a national and international scale.

Comparison of three DNA extraction methods tested on illicit drug-related powders

The detection of human DNA on and within illicit drug preparations is novel and a focus of current research. Previous studies have indicated that certain drug-related powders present in illicit drug preparations can interfere with downstream DNA analysis when directly added to the PCR. Therefore, it is important to determine if these drug-related powders are effectively removed during the DNA extraction or whether traces of powder remain to interfere with DNA processing. Three extraction methods were selected to assess their efficiency at removing drug-related powders for downstream processes using DNA from both saliva and touch depositions. This is the first study to compare efficiencies of DNA extraction methods from drug-related powders. The extraction methods compared were the DNA IQ™ System, the QIAamp® DNA Investigator Kit and the combination of a simple lysis step followed by use of the Microcon® DNA Fast Flow device. Saliva was added to dimethylsulfone (DMS), nitrostyrene and PROSOLV® tablet mixture to determine the effect of powder type (based on solubility). Saliva was also added to 0, 50, 200 and 400 mg of DMS to determine the effect of an increase in DMS quantity. Trace DNA was deposited onto DMS using a worn glove approach. These samples were re-tested six months post-DNA deposition and profiled for further comparisons. Ten replicates were conducted for each condition with five replicates of saliva positive controls per method (n = 255 samples). A subset of samples was chemically analysed to determine if DMS was present in the final DNA eluant. The readily soluble DMS did not interfere with any of the extraction methods at lower amounts, however increasing the DMS to 400 mg reduced the relative DNA yields using the Microcon® and Investigator methods. The tablet mixture reduced the relative DNA yield of all three methods, however the nitrostyrene (which was relatively insoluble) only reduced the relative DNA yield of the DNA IQ™. The Investigator method performed the best with the trace samples, followed by the Microcon® method and then the DNA IQ™. DMS was detected in all extracts chemically analysed from the DNA IQ™ and Microcon®, whereas only one sample tested from the Investigator kit contained DMS in the extract and was in a relatively low amount compared to the other samples. Not one kit outperformed the others in all comparisons, however the Investigator kit was the most efficient overall at optimising the DNA yield whilst also removing the powders more effectively.

Comparison of Illicit Drug Seizures Products of Natural Origin Using a Molecular Networking Approach

Drug powder composition analysis is of particular interest in forensic investigations to identify illicit substance content, cutting agents and impurities. Powder profiling is difficult to implement due to multiple analytical methods requirement and remains a challenge for forensic toxicology laboratories. Furthermore, visualization tools allowing seizure products identification appear to be under-used to date. The aim of this study is to present the utility of molecular networking for the composition establishment of natural origin drugs. A powder suspected to contain heroin and three powders suspected to contain cocaine obtained from law enforcement agency seizures were analyzed using untargeted screening by liquid chromatography coupled with high-resolution mass spectrometry (LC-HRMS/MS). Molecular networking and metabolite annotation applied to suspected heroin sample allowed rapid confirmation of its illicit content (heroin), the identification of structurally related major impurities (6-monoacetylmorphine, 6-monoacetylcodeine, noscapine, and papaverine), as well as cutting agents (acetaminophen and caffeine). The cocaine powder profiling allowed the comparison of its constituents in a semi-quantitative manner (cocaine, benzoylecgonine, trans/cis-cinnamoylcocaine, trimethoxycocaine, hexanoylecgonine methylester, caffeine, hydroxyzine, levamisole, and phenacetin), bringing additional information for their identification, including geographically sourcing of natural product and their putative place in the supply chain. Although this approach does not replace the profiling techniques used by forensic laboratories, the use of molecular networks provides a visual overview of structurally related constituents which aids the comparison and investigation of seizure powders. Molecular networks offers here an ideal way to depict structurally related and unrelated compounds in these often complex mixtures of chemicals.

Impurities, adulterants and cutting agents in cocaine as potential candidates for retrospective mining of GC-MS data

Cocaine is one of the most widely used illicit drugs worldwide. Cocaine powders seized by the Police may contain numerous other substances besides the drug itself. These can be impurities originating from the coca plant or the production process, or be purposely added to the drug formulation as adulterants and cutting agents. In forensic laboratories, identification of cocaine is routinely done through GC-MS analysis, but other components are often ignored even if the method allows for their detection. Yet, they can provide valuable insight into the history of a seizure and its potential connection to other samples. To explore this idea, an extensive review of common impurities and adulterants encountered in cocaine is presented. Based on their incidence, concentration in the end product and compatibility with GC-MS methods, their overall usefulness as candidates for the statistical investigation of existing forensic data is evaluated. The impurities cis- and trans-cinnamoylcocaine, tropacocaine, norcocaine and N-benzoylnormethylecgonine as well as the adulterants lidocaine, procaine, tetracaine, benzocaine, caffeine, acetylsalicylic acid, phenacetin, ibuprofen, levamisole, hydroxyzine and diltiazem are promising candidates to provide additional forensic intelligence. Future research on optimized routine GC-MS methods, signal reproducibility, comparison, statistics and databases is suggested to facilitate this concept. Ultimately, such an approach may significantly advance the amount of information that is extracted from routine casework data, elucidate developments in the cocaine markets in the past and facilitate Police work in the future. Preliminary assessment of existing data from the forensic laboratory of the Amsterdam Police has been included to show that the detection of the identified target impurities is feasible, and that small adjustments to the analysis method could significantly increase the detectability of these analytes in prospective drug screenings. Forensic intelligence based on retrospective data mining of cocaine containing casework samples may thus be realized with minimal additional laboratory efforts by using already available instrumentation, samples and data.

Understanding Australian methylamphetamine drug markets through relational, temporal and spatial analyses

In the area of illicit drugs, forensic case data have proven effective at detecting links between seizures and providing greater insights into illicit drug markets. This research explored the application of mathematical and statistical techniques to several chemical profiles of Australian methylamphetamine seizures. The main aim was to create and deliver a method that would expand the use of illicit drug profiling for strategic intelligence purposes, contributing to the fight against illicit drug trafficking. The use of comparison metrics and clustering analysis to determine links between existing illicit drug specimens and subsequent new specimens was evaluated and automated. Relational, temporal and spatial analyses were subsequently used to gain an insight into illicit drug markets. Relational analysis identified clusters of seizures central to the network. Temporal analysis then provided insights into the behaviour of distribution markets, specifically the emergence and extinction of certain clusters of seizures over time. Spatial analysis aided the understanding of the inter-jurisdictional nature of illicit drug markets. These analyses allowed for the generation of strategic intelligence relating to when and where the Australian methylamphetamine illicit drug market was the most active. Additionally, the strategic level trends identified clusters of seizures that were worth investigating further. These clusters were explored through a case study, which exploited additional chemical profiling data to provide drug market knowledge at an operational level. In turn, the intelligence produced at various levels could allow relevant law enforcement agencies to take necessary measures in disrupting markets.

What is the future of illicit drug profiling in Switzerland? Condemned to disappear or forgotten treasure

Illicit drug profiling bears a long history. Developments in the field from mid-90s have led to several international profiling programs. Several countries have put their efforts to develop and implement the routine use of illicit drug profiling in the investigation and prosecution of illicit drug-related crimes. For more than 20 years, the School of Criminal Sciences (ESC) at the University of Lausanne has, through its illicit drug expertise laboratory, played a main role in promoting the use of illicit drug profiling. In Switzerland, there is no national illicit drug profiling practice and the ESC laboratory is the only one offering such service. However, only a limited number of Swiss jurisdictions send regularly all or part of their seized specimens for analysis to the ESC laboratory. Profiling results are furnished to investigators and prosecutors regardless if they have been requested or not and are stored in a database with limited contextual information with no further data treatment. In 2020, the interruption of a project intended to develop and implement an intercantonal database gathering traditional police data, forensic data (e.g., DNA, fingerprints, etc.), and physical and chemical links, to produce intelligence and support investigation, led to the fundamental question: Is illicit drug profiling in Switzerland condemned to disappear or is it a forgotten treasure, a neglected approach that deserves to be revalued? This paper reports the Swiss situation regarding illicit drug profiling practices and discusses some factors that are thought to impact its use in day-to-day work.

Revealing Unknown Controlled Substances and New Psychoactive Substances Using High-Resolution LC-MS/MS Machine Learning Models and the Hybrid Similarity Search Algorithm

High-resolution LC-MS/MS tandem mass spectra-based machine learning models are constructed to address the analytical challenge of identifying unknown controlled substances and new psychoactive substances (NPS's). Using a training set comprised of 770 LC-MS/MS barcode spectra (with binary entries 0 or 1) obtained generally by high-resolution mass spectrometers, three classification machine learning models were generated and evaluated. The three models are artificial neural network (ANN), support vector machine (SVM), and k-nearest neighbor (k-NN) models. In these models, controlled substances and NPS's were classified into 13 subgroups (benzylpiperazine, opiate, benzodiazepine, amphetamine, cocaine, methcathinone, classical cannabinoid, fentanyl, 2C series, indazole carbonyl compound, indole carbonyl compound, phencyclidine, and others). Using 193 LC-MS/MS barcode spectra as an external test set, accuracy of the ANN, SVM, and k-NN models were evaluated as 72.5%, 90.0%, and 94.3%, respectively. Also, the hybrid similarity search (HSS) algorithm was evaluated to examine whether this algorithm can successfully identify unknown controlled substances and NPS's whose data are unavailable in the database. When only 24 representative LC-MS/MS spectra of controlled substances and NPS's were selectively included in the database, it was found that HSS can successfully identify compounds with high reliability. The machine learning models and HSS algorithms are incorporated into our home-coded AI-SNPS (artificial intelligence screener for narcotic drugs and psychotropic substances) standalone software that is equipped with a graphic user interface. The use of this software allows unknown controlled substances and NPS's to be identified in a convenient manner.

Cocaine profiling method retrospectively developed with nontargeted discovery of markers using liquid chromatography with time-of-flight mass spectrometry data

Illicit drug profiling performed by forensic laboratories assists law enforcement agencies through providing information about chemical and/or physical characteristics of seized specimens. In this article, a model was developed for the comparison of seized cocaine based on retrospective analysis of data generated from ultrahigh performance liquid chromatography with time‐of‐flight mass spectrometry (UHPLC‐TOF‐MS) comprehensive drug screening. A nontargeted approach to discover target compounds was employed, which generated 53 potential markers using data from cocaine positive samples. Twelve marker compounds were selected for the development of the final profiling model. The selection included a mixture of commonly used cocaine profiling targets and other cocaine‐related compounds. Combinations of pretreatments and comparison metrics were assessed using receiver operating characteristic curves to determine the combination with the best discrimination between linked and unlinked populations. Using data from 382 linked and 34,519 unlinked distances, a classification model was developed using a combination of the standardization and normalization transformations with Canberra distance, resulting in a linked cut‐off with a 0.5% false positive rate. The present study demonstrates the applicability of retrospectively developing a cocaine profiling model using data generated from UHPLC‐TOF‐MS nontargeted drug screening without pre‐existing information about cocaine impurities. The developed workflow was not specific to cocaine and thus could potentially be applied to any seized drug in which there are both sufficient data and impurities present.

DNA on drugs! A preliminary investigation of DNA deposition during the handling of illicit drug capsules

DNA profiling from capsules and tablets offers a complementary tool to that of chemical profiling when investigating the manufacture and trade in illicit drugs. By sampling the outside of capsules, individuals who may have handled them during production, assembly or distribution may have deposited their DNA and can be identified if matched to a nominated profile or one on a relevant DNA database. The profiles can also be compared to those found on other capsules to potentially link various drug seizures. This study sampled the exterior of capsules after they had been handled in a controlled scenario to determine if informative DNA profiles could be generated from this brief contact. Two individuals of intermediate shedder status washed their hands and waited for 30 min before handling ten gelatine, vegetable, and enteric vegetable capsules each (n = 60). Contact was made for 15 s. Each capsule was swabbed and DNA isolated. The amount of recovered human DNA was quantified and profiled using the Verifiler Plus DNA profiling kit. Profiles were generated from 82% (49/60) of capsules tested with LR values above 1 × 10³ for the inclusion of the volunteer as a contributor. Inhibition of the PCR was detected in 24 of the 60 samples, however 16 of these still produced informative profiles when sufficient template DNA was available and only mild inhibition was detected, or by overcoming inhibition by dilution of the DNA extract. This pilot study demonstrates the potential for forensic science laboratories to recover human DNA from the exterior surface of capsules which are commonly used to encase illicit drugs such as MDMA, thus enabling both biological and chemical profiling methods to contribute to the investigation of clandestine drug production and distribution.

Illicit drug profiling practices in Finland: An exploratory study about end users' perceptions

Illicit drug profiling (i.e. chemical and/or physical profiling) to compare and relate illicit drugs samples has been actively used in routine case work at the National Bureau of Investigation (NBI) in Finland. This preliminary and exploratory work reviews NBI's illicit drug profiling practices. Particular emphasis is put on communication of forensic results and how the NBI has promoted the use of forensic data in an intelligence perspective by establishing a case coordination service. Moreover, our study evaluates the comprehension, integration and usefulness of illicit drug profiling from end users' point of view by means of an online survey and face-to-face interviews. Findings are compared with theoretical aspects as described in literature. Results show that in the Finnish context illicit drug profiling is used and useful in the investigation and in court. From end users' perspective, real practical relevance relies in its use as intelligence during the investigation. However, to be truly useful, illicit drug profiling results must be communicated promptly during the investigation, with sufficient clarity and interpreted correctly by end users. Factors influencing the integration of illicit drug profiling in the forensic process are addressed.

Combined Colorimetric and Electrochemical Measurement Paper-Based Device for Chemometric Proof-of-Concept Analysis of Cocaine Samples

Cocaine (COC) is one of the most widely consumed illegal drugs around the world. Street COC is commonly adulterated with pharmaceutical compounds that mimic or intensify the COC's sensory effect. Adulteration is performed to increase the profit of criminal organizations and each one has their own way of doing it. Therefore, determining the composition of seized COC samples (chemical profile) provides evidence for the police to track criminal organization networks and their activity patterns. Using filter paper as a substrate, we developed a multiple detection paper-based analytical device (PAD) that combines colorimetric and electrochemical measurements to discriminate COC samples according to adulterant's content. A regular graphite lead modified with a gold film made from Au leaf (graphite/Au) to improve electron transfer was used as a working electrode. Silver and Ag/AgCl were used as auxiliary and reference electrodes, respectively. The colorimetric device was patterned using a laser cutter and coupled to the electrochemical device using a double-sided tape, allowing simultaneous analysis to gather more analytical information about COC samples. Graphite/Au was characterized by scanning and transmission electron microscopies and electrochemical assays. The simultaneous colorimetric and electrochemical analyses combined to principal component analysis improved the analytical characterization of COC trial samples and provided a fast discrimination based on the assembled database.

Interpol review of controlled substances 2016-2019

This review paper covers the forensic-relevant literature in controlled substances from 2016 to 2019 as a part of the 19th Interpol International Forensic Science Managers Symposium. The review papers are also available at the Interpol website at: https://www.interpol.int/content/download/14458/file/Interpol%20Review%20Papers%202019.pdf.

When does the cutting of cocaine and heroin occur? The first large-scale study based on the chemical analysis of cocaine and heroin seizures in Switzerland

BACKGROUND

Illicit drug profiling can provide knowledge about illicit drug markets, informing on the level of distribution and its evolution in space and time. Illicit drug profiling is usually limited to impurities originally present in the illicit drug (e.g. alkaloids, co-extracted compounds or by-products). However, the benefit of a comprehensive analysis of cutting agents in drug seizures for law enforcement agencies, intelligence and health policy has not been thoroughly investigated in the literature and is the focus of this research.

AIM

This research aims at assessing when and how cutting (i.e. adulteration and dilution) occurs in the supply chain by analysing cocaine and heroin seizures made between 2006 and 2015 in Switzerland.

METHODS

Cocaine and heroin seizures made along the supply chain by law enforcement agencies in the Western region of Switzerland were investigated for adulteration and dilution. A total number of 7841 cocaine and 3476 heroin specimens coming from 1341 and 721 seizures, respectively, were analysed.

RESULTS

The results show that, for both illicit drugs, adulteration and/or dilution occur before arrival into Switzerland as well as in Switzerland. While cocaine is adulterated and diluted, heroin is only adulterated. Interestingly, the same mixture of adulterants (i.e. caffeine-paracetamol) is used to cut heroin at each step in the supply chain.

CONCLUSION

Gaining knowledge about adulteration and dilution at different stages in the supply chain enhances our understanding of drug markets. It also highlights differences along the supply chain and in the distribution of both drugs in Switzerland.

Chemometrics in forensic chemistry - Part I: Implications to the forensic workflow

The forensic literature shows a clear trend towards increasing use of chemometrics (i.e. multivariate analysis and other statistical methods). This can be seen in different disciplines such as drug profiling, arson debris analysis, spectral imaging, glass analysis, age determination, and more. In particular, current chemometric applications cover low-dimensional (e.g. drug impurity profiles) and high-dimensional data (e.g. Infrared and Raman spectra) and are therefore useful in many forensic disciplines. There is a dominant and increasing need in forensic chemistry for reliable and structured processing and interpretation of analytical data. This is especially true when classification (grouping) or profiling (batch comparison) is of interest. Chemometrics can provide additional information in complex crime cases and enhance productivity by improving the processes of data handling and interpretation in various applications. However, the use of chemometrics in everyday work tasks is often considered demanding by forensic scientists and, consequently, they are only reluctantly used. This article and following planned contributions are dedicated to those forensic chemists, interested in applying chemometrics but for any reasons are limited in the proper application of statistical tools - usually made for professionals - or the direct support of statisticians. Without claiming to be comprehensive, the literature reviewed revealed a sufficient overview towards the preferably used data handling and chemometric methods used to answer the forensic question. With this basis, a software tool will be designed (part of the EU project STEFA-G02) and handed out to forensic chemist with all necessary elements of data handling and evaluation. Because practical casework is less and less accompanied from the beginning to the end out of the same hand, more and more interfaces are built in through specialization of individuals. This article presents key influencing elements in the forensic workflow related to the most meaningful chemometric application and evaluation.

Cocaine adulteration

Cocaine is a naturally occurring and illicitly used psychostimulant drug. Cocaine acts at monoaminergic neurotransmitter transporters to block uptake of the monoamines, dopamine, serotonin and norepinephrine. The resulting increase of monoamines in the extracellular space underlies the positively reinforcing effects that cocaine users seek. In turn, this increase in monoamines underlies the development of addiction, and can also result in a number of severe side effects. Currently, cocaine is one of the most common illicit drugs available on the European market. However, cocaine is increasingly sold in impure forms. This trend is driven by cocaine dealers seeking to increase their profit margin by mixing ("cutting") cocaine with numerous other compounds ("adulterants"). Importantly, these undeclared compounds put cocaine consumers at risk, because consumers are not aware of the additional potential threats to their health. This review describes adulterants that have been identified in cocaine sold on the street market. Their typical pharmacological profile and possible reasons why these compounds can be used as cutting agents will be discussed. Since a subset of these adulterants has been found to exert effects similar to cocaine itself, we will discuss levamisole, the most frequently used cocaine cutting agent today, and its metabolite aminorex.