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Abstract Synthetic cocaine analogs are designer drugs that recently emerged as non‐controlled substitutes for their parent drug. Among them, nitracaine is of particular concern for its psychoactive effect. In this work, we present a thorough characterization of the electrochemical behavior of nitracaine, with a final quantification performed by differential pulse voltammetry (DPV) in ethanol/lithium perchlorate 0.1 M. The selectivity of the method and reproducibility of results were assessed. LOQ of 0.3 μg mL−1 and a linear dynamic range of up to 400 μg mL−1 were obtained. In addition, recoveries from 85 % to 101 % were achieved on both simulated and real samples. For nitracaine analysis in urine, a clean‐up and a preconcentration step by solid phase extraction (SPE) using the adsorbent Florisil have been developed and optimized through the Design of Experiments (DoE) strategy, thus achieving an enrichment factor of 20.

Favipiravir, a pyrazine analog, is proposed as providential antiviral agent against the COVID-19 infection during 2020 pandemic emergency. For the first time, a fabric phase sorptive extraction (FPSE) combined with gas chromatography-mass spectrometry (GC-MS) has been developed and applied for the determination of favipiravir (FAV) in biological samples (human plasma, blood and urine), pharmaceutical and forensic samples. The method comprises of extraction of FAV by FPSE followed by its derivatization with N, O-bis (trimethylsilyl) trifluoroacetamide (BSTFA) and GC-MS analysis. Design of experiment-based optimization was performed using Placket-Burman Design (PBD) and Central Composite Design (CCD) for the screening of significant factors of FPSE and their optimization, respectively. Among all tested membranes, sol-gel polyethylene glycol (PEG) has offered the best extraction efficiency for FAV. Under optimum conditions, the proposed method was found to be linear in the range of 0.01–10 µg mL−1 by GC-MS. The LODs and LOQs were as low as 0.001-0.0026 µg mL−1 and 0.003-0.0086 µg mL−1, respectively by GC-MS. Intra-day and inter-day precisions were less than 5 and 10%, respectively, showing good method precision. The proposed method has been successfully applied to detect and quantify FAV in human urine, whole blood and plasma samples along with seized forensic samples. In addition, the proposed method has been evaluated for its green character by ComplexGAPI index.

The article identifies a number of problems that arose in the process of training students in chemistry at Ukrainian universities in the 19th – early 20th centuries. There were not enough chemistry teachers during this period, but they did a lot of work to find ways to stimulate students’ research, although chemical laboratories were insufficiently equipped and staffed. The role of university professors in public life and everyday problems of the population of Ukraine is shown. They participated in the preparation of literature for the population of Kharkiv and Odessa, provided assistance in studying the physical and chemical properties of products and non-product substances. During this period, new areas of focus emerged in the study of chemistry (agrochemistry, thermochemistry, electrochemistry, etc.). The problems of various scientific schools in chemistry, which led to conflicts among lecturers, university administrations and the Ministry of Public Education, are considered. During this period, the authorities tightened control over the national factor of university teachers. At the end of the 19th century the Ministry of Public Education demanded to strengthen the Russian element in the teaching staff, refrained from hiring teachers of the Jewish and Catholic religion. The article also considers the problems of scientific trips of teachers abroad and the use in teaching students of foreign experience in teaching chemistry.

Reports related to incidences of drug facilitated crimes (DFCs) have notably increased in recently. In such cases, victims report being assaulted or robbed while under the influence of drugs. Lorazepam (LZ) is frequently used in DFCs as it can easily make victims docile owing to its potent numbing effect. Therefore, a straightforward and green analytical method to analyze LZ in spiked food matrices in connection with criminal acts becomes important. The current study reports a simple, green, and high sample throughput analytical method for determining LZ in food and drink matrices commonly encountered in DFCs, based on recently introduced cellulose paper sorptive extraction (CPSE). For the extraction of LZ from food matrices, pristine cellulose paper (CP, commonly used laboratory filter paper) was used as a sorptive medium. Five pieces of CP (1.5″ × 1.5″ each) were dipped into diluted food matrices (cream biscuits and tea) and stirred on a rotary shaker for 30 min at 200 rpm. The CPs were then dried, and the adsorbed LZ was back-extracted into 2 mL of methanol. The extract was then subjected to GC–MS analysis in selected ion monitoring (SIM) mode. Several parameters, including CP size and number, back-extraction solvent type and volume, sample volume, extraction time and stirring speed, pH, ionic strength, elution time and speed, were thoroughly screened and optimized. Under the optimized conditions, the method was found to be linear in the range of 0.2–10 µg·mL−1 (or µg·g−1) with a coefficient of determination (R2) ranging from 0.996–0.998. The limit of detection and limit of quantification for cream biscuits were 0.054 and 0.18 µg·g−1 whereas they were 0.05 and 0.16 µg·mL−1 for tea samples. For all measurements, the relative standard deviations (%RSD) were always below 10%. Two mL of methanol per sample was used during the entire sample preparation process. The greenness of the proposed procedure was evaluated using Analytical Eco-Scale and GAPI greenness assessment tools. Finally, the CPSE–GC–MS method has been applied for the determination of LZ in forensic food samples which were used in DFCs.

The use of anabolic androgenic steroids is largely restricted worldwide since they are associated with innumerous side effects and health damage. However, apprehensions of formulations of anabolic agents have been extensively increasing throughout the world, making their analysis a common task in the forensic field. In this sense, a set of three experiments was developed and applied to undergraduate students of Forensic Chemistry dealing with visual inspection of apprehended formulations of anabolic androgenic steroids as well as chemical identification by Infrared Spectroscopy and Gas Chromatography-Mass Spectrometry. Moreover, the classroom evaluated the extraction of steroidal active ingredients by ultrasonic and microwave-assisted extraction. The experimental procedures allied with the theory behind these topics provided an important background to the students on distinct extraction methods and analytical techniques used in the analysis of anabolic agents. Finally, the classroom was led to critically evaluate and interpret the results as well as to question the adequacy of experimental methods used in forensic analysis to stimulate their critical thinking.

MDMA is the abbreviation for 3,4-methylenedioxymethamphetamine, which is commonly found in “ecstasy” pills. The psychoactive and euphoric effects that MDMA causes make this substance an illicit drug that is constantly seized by police forces. We describe a low-cost and fast voltammetric methodology that requires a carbon paste electrode (working electrode) in aqueous solution containing 0.1 mol L-1 LiClO4 as the supporting electrolyte. We conducted cyclic and square wave voltammetry and obtained limits of detection of 0.33 μg mL-1 and 0.36 μg mL-1, respectively, as others figures of merit for a complete validation. It includes the analysis main interfering substances, and results for seized samples were compared to those obtained by chromatography, which were close. An extended study of robustness were carried out by Youden’s test, that is inedited to electrochemical techniques when applied to forensic analysis. This test contributes to complete methodology validation and study of electrode cost and efficiency during electrochemical measurements involving a carbon paste electrode. In the end, this work presents a full validated methodology able to be applied in forensic laboratories.

The consequences of consuming and commercializing illicit drugs including cocaine, con­stitute a serious problem for authorities and the whole society. Cocaine is usually identified in the laboratory conditions by chromatographic or spectroscopic methods. Electro­che­mical techniques have also gained prominence because they are fast and easy to use, have many applications, and provide reproducible and reliable results. Therefore, in the present study, a voltammetric method was developed to detect freebase cocaine using carbon paste electrode and methanol as the main cocaine solvent. The developed method was applied to detect cocaine in the artificial saliva by the square wave voltammetry (SWV). The current values increased linearly with the concentration of cocaine, which afforded construction of the analytical curve. The limit of detection (LoD) and the limit of quantify­cation (LoQ) were determined as 0.90 µg/mL and 2.41 µg/mL, respectively. For compa­rison purposes, HPLC-DAD chromatographic method was also applied to detect cocaine. The corresponding analytical curve gave LoD = 0.043 µg/mL and LoQ = 0.130 µg/mL. Although showing better analytical results, HPLC-DAD method could not detect cocaine in saliva samples without previous treatment, what makes the electrochemical method much more attractive for this type of detection.

New Psychoactive Substances (NPS) present several identification and public health challenges. However, experimental studies with illicit substances can involve regulatory restrictions, and obtaining information about them can be time-consuming. In this scenario, in silico methods can help to monitor the emergence of new synthetic substances such as synthetic cathinones, some of the most seized NPS. Here, we study the cathinone alpha-PVP or Flakka by theoretical chemistry methods to evaluate its structure, possible conformers, and spectroscopic profile. Initially, we performed a systematic conformational analysis and an analysis based on the Boltzmann distribution. We determined the most probable experimental structure and compared it to the crystallographic structure, to verify similarity between the forms. Next, we applied the factorial design to the obtained structure so that we could decide on the most adequate computational method to obtain the spectrum in the infrared and NMR region. Then, we compared the results with experimental data available in the literature. Finally, we evaluated multivariate statistical methods to ensure that we would come to conclusions based on the responses of each step. All the steps indicated similarity between the theoretical data and the experimental results when we used the combination DFT B3LYP and the basis 6-31G**. Our results demonstrate the potential application of computer simulation in forensic chemistry and provide valuable spectroscopic and structural information about illegal substances.

Forensic chemistry deals with the analysis of various types of physical evidences related to crime, corresponding to the detection of target substances or elements in complex matrices. There is a vital need for highly selective, rapid, and sensitive biosensing technologies in heavy metal ions analysis especially those from living persons, autopsy, food, water, soil, and other identified substances at very preliminary stages. Fluorescent materials-based method for heavy metal ions detection is one of the most important analytical methods, resulting in the ability to measure analytes in complex matrices with unsurpassed selectivity and sensitivity. In this mini review, different fluorescent materials-based analytical methods aiming at several heavy metal ions detection are exclusively reviewed through a comprehensive literature survey. In addition, current challenges to achieve integrated evidence analysis process are briefly discussed to provide an outlook for heavy metal ions detection based on fluorescent analytical methods in the forensic chemistry field.

Promezio is a famous Italian chemistry professor who is searching for missing element n. 61. In 1924 his laboratory is partially destroyed by a fire and he disappears. Almost one hundred years later high school students are recruited to investigate this strange case. “The strange case of Professor Promezio” represents a unicum in the panorama of laboratory activities for high school students: it is a cold case in which students are asked to investigate a fact that took place almost a century ago. Through the chemical analysis of different findings, the connection with historical events of that period, the study of the suspects' interrogation reports, the reproduction of the experiments conducted by Professor Promezio, the students will identify the possible culprit. A complex scientific problem is solved exploring different areas of chemistry and, in addition, interconnections with history, geography, ethics and other school subjects are deepened.

Quinolin-8-yl 1-(5-fluoropentyl)-1H-indole-3-carboxylate (5-Fluoro-PB-22 or 5F-PB-22; QUPIC N-(5-fluoropentyl) analog), is a synthetic cannabinoid which mimics the effects of cannabis. Several countries have reported numerous detections of this compound and its abuse has led to adverse effects including death. The aim of this study was to separate and identify the fluoropentyl positional isomers of fluoro-PB-22 using gas chromatography-mass spectrometry, solid deposition gas chromatography-infrared detection spectroscopy and 1H and 13C nuclear magnetic resonance spectroscopy. Data acquired from these multiple techniques can assist forensic laboratories lacking the reference drug standard(s) to identify the specific isomer of fluoro-PB-22 in seized material. [ABSTRACT FROM AUTHOR]

In this paper, insight into forensic science students' experiences of a case-based scenario with an interdisciplinary guided-inquiry experience in chemistry and biology is presented. Evaluation of student experiences and interest showed that the students were engaged with all aspects of the case-based scenario, including the curriculum theory components as well as the active learning within interdisciplinary laboratories. Working in groups of three during laboratories was favored by students, but mixed responses for group assessment were observed. Since the introduction of the case-based scenario, sustained improvements in student assessment outcomes were observed. Questionnaire respondents indicated a strong interest in case-based learning. We propose a methodology framework for the case-based scenario investigation in forensic science and discuss the student experiences and improved learning occurring with the scenario involving an interdisciplinary guided-inquiry experience in chemistry and biology. This work suggests that an interdisciplinary guided-inquiry learning approach, ideally contextualized within a case-based scenario, is adaptable to other science discipline combinations. [ABSTRACT FROM AUTHOR]

Marijuana (Cannabis sativa L.) is the most cultivated, trafficked and consumed illicit drug worldwide. Estimates indicate 10% of individuals experiencing marijuana become daily users, and 20-30% use it weekly. Around 489 natural compounds have been identified in this plant, of which 70 are cannabinoids, responsible for psychic effects. The most relevant cannabinoid is Δ9-THC, recognized as the main chemical substance with psychoactive effects. The aims of this work was to investigate whether other drugs interfere with the colorimetric tests Fast Blue B and Duquenois-Levine, widely used for marijuana screening in forensic chemistry laboratories.

In cases of suspected arson, a body may be intentionally burnt to cause loss of life, dispose of remains, or conceal identification. A primary focus of a fire investigation, particularly involving human remains, is to establish the cause of the fire; this often includes the forensic analysis of fire debris for the detection of ignitable liquid residues (ILRs). Commercial containers for the collection of fire debris evidence include metal cans, glass jars, and polymer/nylon bags of limited size. This presents a complication in cases where the fire debris consists of an intact, or partially intact, human cadaver. This study proposed the use of a body bag as an alternative sampling container. A method was developed and tested for the collection and analysis of ILRs from burnt porcine remains contained within a body bag using dynamic headspace sampling (using an Easy-VOC™ hand-held manually operated grab-sampler and stainless steel sorbent tubes containing Tenax TA) followed by thermal desorption comprehensive two-dimensional gas chromatography–time-of-flight mass spectrometry (TD-GC×GC-TOFMS). The results demonstrated that a body bag containing remains burnt with gasoline tested positive for the presence of gasoline, while blank body bag controls and a body bag containing remains burnt without gasoline tested negative. The proposed method permits the collection of headspace samples from burnt remains before the remains are removed from the crime scene, limiting the potential for contamination and the loss of volatiles during transit and storage.

Fast and reliable information is crucial for first responders to draw correct conclusions at crime scenes. An ambient pressure laser desorption (APLD) mass spectrometer is introduced for this scenario, which enables detecting substances on surfaces without sample pretreatment. It is especially useful for substances with low vapor pressure and thermolabile ones. The APLD allows for the separation of desorption and ionization into two steps and, therefore, both can be optimized separately. Within this work, an improved version of the developed system is shown that achieves limits of detection (LOD) down to 500 pg while remaining fast and flexible. Furthermore, realistic scenarios are applied to prove the usability of this system in real-world issues. For this purpose, post-blast residues of a bomb from the Second World War were analyzed, and the presence of PETN was proven without sample pretreatment. In addition, the analyzable substance range could be expanded by various drugs and drug precursors. Thus, the presented instrumentation can be utilized for an increased number of forensically important compound classes without changing the setup. Drug precursors revealed a LOD ranging from 6 to 100 ng. Drugs such as cocaine hydrochloride, heroin, (3,4-methylendioxy-methamphetamine) hydrochloride (MDMA) hydrochloride, and others exhibit a LOD between 10 to 200 ng.