Luiz F.C. Sinhorini
Bio: Luiz F.C. Sinhorini is an academic researcher from Faculdade de Filosofia, Ciências e Letras de Ribeirão Preto. The author has contributed to research in topics: Identification (biology). The author has an hindex of 1, co-authored 2 publications receiving 3 citations.
Topics: Identification (biology)
29 Sep 2021
TL;DR: The main characteristics of each group and certain aspects of presumptive and confirmatory tests regarding these groups are presented, and obstacles in developing methodologies that can correctly identify these substances are shown.
Abstract: Correct identification of substances is essential to understand drug use and trafficking trends and guide measures for harm reduction and treatment. Two steps are needed to verify the nature of a substance properly: a presumptive test and a confirmatory test. There are presumptive tests which presents deficiencies, such as providing false-positive and false-negative results. Confirmatory tests are more reliable, but they are more expensive. With the appearance of New Psychoactive Substances (NPS), identifying and characterizing illicit substances has become more challenging. This paper focuses on presenting information about NPS characteristics and analysis. For this purpose, we have reviewed the literature to address the main aspects of five groups of NPS: amphetamine-type stimulants, synthetic cannabinoids, N-methoxybenzyl-methoxyphenylethylamine (NBOMe), synthetic opioids, and benzodiazepines. We present the main characteristics of each group and certain aspects of presumptive and confirmatory tests regarding these groups. Our findings show obstacles in developing methodologies that can correctly identify these substances, and problems can increase as new structures appear. This information can be helpful to drive research into identifying NPS and inform law enforcement and law practitioners about the main characteristics of each group and the main questions involving their identification.
TL;DR: In this article, the authors applied factorial design to decide the best conditions to perform quantum calculations to obtain the infrared spectra of 46 seized nonpharmaceutical fentanyls (NPFs) and used multivariate classification to establish the main spectral characteristics of these substances.
Abstract: Non-pharmaceutical fentanyls (NPFs) are synthetic substances analogous to fentanyl that have not been approved for medical use. Their clandestine synthesis involves chemical modification of an existing drug, which may cause unpredictable pharmacological effects. New structures are emerging rapidly, and there is a lack of information for characterization. It makes their chemical identification difficult. In this scenario, in silico methods have become an alternative to study these systems. Here, we have applied factorial design to decide the best conditions to perform quantum calculations to obtain the infrared spectra of 46 seized NPFs. A multivariate classification was used to establish the main spectral characteristics of these substances. Similarities between theoretical and experimental spectra were determined through vibrational frequencies comparison, Kullback-Leibler divergence, and SIMCA evaluation. The in silico methods provided valuable information about illegal substances and proved helpful in predict the spectroscopic properties of new fentanyl analogous drugs.
01 Jan 2013
TL;DR: In this paper, a presumptive test for synthetic cannabinoids was proposed using benzophenone (BP) and its ketone as a possible reaction site, and the results showed that the ketones on BP and JWH-019 were reluctant to react.
Abstract: Synthetic cannabinoids (SC’s) began to gain popularity around the world in 2009. Since then, many of the compounds have been outlawed and methods developed to detect them and their metabolites using mass spectrometry. Our work investigated the possibility of developing a colorimetric presumptive test. The SC JWH-019 was synthesized and its ketone targeted as a possible reaction site. Many SC’s contain ketones and thus a reaction at this site would be applicable to many of the compounds. Since JWH-019 is costly and time consuming to synthesize, much of the experimental work was done using benzophenone (BP). BP contains a diaryl ketone making it comparable to JWH-019. Our initial work studied existing presumptive tests, one for SC’s and one for cannabis. Both gave negative results for JWH-019. From there, we looked at synthesizing imines that might be colored. We studied reactions using dinitrophenylhydrazone, hydrazine, aniline and neutral red. Through these reactions it became apparent that the ketones on BP and JWH-019 were reluctant to react. Finally, we studied forming imines of BP with either ethylenediamine (en) or semicarbazide. The resulting product was then used to produce a metal complex. A complex formed between the en-BP product and Cu 2+ provided a change in color, but the en-BP imine proved difficult to obtain and the results were not consistent.
TL;DR: A silica gel thin-layer chromatography (TLC) plate with the lower third impregnated with Ag(I) ions enabled within minutes a digital chromatographic separation of strongly retained CBD analogues and poorly retained THC analogues, which would allow rapid distinction between high and low THC varieties of cannabis, with the potential for on-site applicability.
Abstract: With the ever-evolving cannabis industry, low-cost and high-throughput analytical methods for cannabinoids are urgently needed. Normally, (potentially) psychoactive cannabinoids, typically represented by Δ9-tetrahydrocannabinol (Δ9-THC), and nonpsychoactive cannabinoids with therapeutic benefits, typically represented by cannabidiol (CBD), are the target analytes. Structurally, the former (tetrahydrocannabinolic acid (THCA), cannabinol (CBN), and THC) have one olefinic double bond and the latter (cannabidiolic acid (CBDA), cannabigerol (CBG), and CBD) have two, which results in different affinities toward Ag(I) ions. Thus, a silica gel thin-layer chromatography (TLC) plate with the lower third impregnated with Ag(I) ions enabled within minutes a digital chromatographic separation of strongly retained CBD analogues and poorly retained THC analogues. The resolution (Rs) between the closest two spots from the two groups was 4.7, which is almost 8 times higher than the resolution on unmodified TLC. After applying Fast Blue BB as a chromogenic reagent, smartphone-based color analysis enabled semiquantification of the total percentage of THC analogues (with a limit of detection (LOD) of 11 ng for THC, 54 ng for CBN, and 50 ng for THCA when the loaded volume is 1.0 μL). The method was validated by analyzing mixed cannabis extracts and cannabis extracts. The results correlated with those of high-performance liquid chromatography with ultraviolet detection (HPLC-UV) (R2 = 0.97), but the TLC approach had the advantages of multi-minute analysis time, high throughput, low solvent consumption, portability, and ease of interpretation. In a desiccator, Ag(I)-TLC plates can be stored for at least 3 months. Therefore, this method would allow rapid distinction between high and low THC varieties of cannabis, with the potential for on-site applicability.
01 Jan 2018
TL;DR: In this article, the synthesis of a number of fluorinated and non-fluorinated diphenidine and ephenidine derivatives is presented, with results confirmed by GC-MS.
Abstract: In recent years Novel Psychoactive Substances (NPS), including diphenidine and ephenidine, have emerged and an increase in the number of substances encountered each year has increased, even with the introduction of the Psychoactive Substances Act (2016).1 More derivatives are also reported containing fluorine substituents due to the increased stability.2 The appearance of novel fluorinated substances creates analytical challenges for their detection. This results in the need for the development of new rapid, selective and inexpensive analytical methods for both their separation and detection. Colour test reagents are commonly used for the presumptive testing of these emerging substances, however as the number of encountered compounds increases so does the number of false positives produced with these tests.3 Gas Chromatography-Mass Spectroscopy (GC-MS) is also a commonly used method for the detection and separation of controlled substances, with methods reported previously for fluorinated cathinones.4 However, it also reports on the tailing of peaks through thermal degradation, which makes separation of regioisomers difficult. This thesis demonstrates the synthesis of a number of fluorinated and non- fluorinated diphenidine and ephenidine derivatives. Synthesis of fluorinated diphenidine analogues will also outline the ease of production of NPS along with the difficulties in their detection and separation. The use of presumptive colour testing shows the difficulty of distinguishing between regioisomers, as well as the increase to the number of false positives. The development of GC-MS methods has aided with the separation and detection of diphenidine and ephenidine derivatives. A method has also been developed and validated for the identification of fluorinated cathinones and amphetamines with improved symmetry and a removal of any tailing/fronting. Runs for all separation and identification last 20 minutes or longer. 60 MHz NMR has the ability to perform 1H and 19F NMR experiments, while still providing matching spectrum patterns and splitting to higher-powered magnets. This is utilised for the detection of diphenidine, ephenidine, cathinone and amphetamine derivatives with the ability to distinguish between regioisomers. 2D NMR experiments can also allow for further identification of difluorinated ephenidine derivatives. This allows for the possibility of using 60 MHz NMR as a presumptive test for NPS. The use of 19F NMR experiments also provides an ability to perform quantitative analysis. Street samples can then be analysed both quantitatively and quantitatively, using 60 MHz NMR, with results confirmed by GC-MS. All 1H and 19F NMR experiments occur within 5 minutes meaning detection can occur rapidly which aids with forensic testing and shows that 60 MHz instrumentation can be utilised at locations such as festivals, airport security and police custody.