Gabriela Vanini

Qualitative analysis of designer drugs by paper spray ionisation mass spectrometry (PSI-MS)

The application of ambient ionization mass spectrometry such as paper spray ionisation (PSI) is a fast, powerful, and simple method to analyze designer drugs directly on the surface of blotters. PSI-MS does not require nebulizing gas and heating temperature as well as complex protocols for sample preparation. Herein, it was possible to identify and elucidate the chemical structure of designer drugs using tandem mass spectrometry experiments from a triangular blotter. Substances such as lysergic acid diethylamide (LSD), and five new designer drugs (2,5-dimethoxy-4-chloroamphetamine (DOC), 2,5-dimethoxy-4-bromoamphetamine (DOB), 25C-NBOMe, 25B-NBOMe, and 25I-NBOMe) were characterized by PSI-MS. The PSI(+)-MS and PSI(+)-MS/MS data confirmed the assignments of the designer drugs and fragmentation mechanisms have been proposed. From losses of 17 Da (NH3), which is typical of primary amines, the CID results suggest the presence of isomers in the chemical composition of the NBOMe class. Additionally, the data were compared to those of ultra-high-resolution mass spectroscopy (positive-ion electrospray ionization coupled with Fourier transform ion cyclotron mass spectrometry, ESI(+)FT-ICR MS).

2-(4-iodo-2,5-dimetoxifenil)-n-[(2-metoxifenil)metil]etamina ou 25i-nbome: caracterização química de uma designer drug

Drug trafficking and the introduction of new drugs onto the illicit market are one of the main challenges of the forensic community. In this study, the chemical profile of a new designer drug, 2-(4-iodine-2,5-dimethoxyphenyl)-n-[(2-methoxyphenyl)methyl]etamine or 25I-NBOMe was explored using thin layer chromatography (TLC), ultraviolet-visible spectrophotometry (UV-Vis), attenuated total reflection with Fourier transform infrared spectroscopy(ATR-FTIR), gas chromatography mass spectrometry (GC-MS) and electrospray ionization Fourier transform ion cyclotron resonance mass spectrometry (ESI-FT-ICR MS). First, the TLC technique was effective for identifying spots related to 25C-, 25B- and 25I-NBOMe compounds, all with the same retention factor, Rf ≈ 0.50. No spot was detected for 2,5-dimethoxy-4-bromoamphetamine, 2,5-Dimethoxy-4-chloroamphetamine or lysergic acid diethylamide compounds. ATR-FTIR preserved the physical-chemical properties of the material, whereas GC-MS and ESI-MS showed better analytical selectivity. ESI(+)FT-ICR MS was used to identify the exact mass (m/z428.1706 for the [M + H]+ ion), molecular formula (M = C18H22INO3), degree of unsaturation (DBE = 8) and the chemical structure (from collision induced dissociation, CID, experiments) of the 25I-NBOMe compound. Furthermore, the ATR-FTIR and CID results suggested the presence of isomers, where a second structure is proposed as an isomer of the 25I-NBOMe molecule.

Chemical profiling and classification of cannabis through electrospray ionization coupled to Fourier transform ion cyclotron resonance mass spectrometry and chemometrics

Cannabis sativa is chemically characterized as containing terpenophenolic structures, named cannabinoids, which are exclusively found in this plant. In Brazil, the international trafficking of small amounts of cannabis seeds by transport companies has significantly grown in recent years. In this context, combining the chemical profiling data of cannabis with chemometric techniques provides investigative forces with information towards interrupting such illegal activities. In this paper, 68 samples of cannabis seeds from seizures performed by the Brazilian Federal Police were germinated, planted, and cultivated under controlled conditions in a greenhouse, and analyzed by positive and negative electrospray ionization coupled to Fourier transform ion cyclotron resonance mass spectrometry (ESI(±)-FT-ICR MS and ESI(±)MS/MS) techniques considering different growth periods. The chemical profiling using ESI(+)FT-ICR MS enabled the detection of 123 species as cannabinoid compounds or metabolites and 8 non-cannabinoid constituents. The multivariate techniques applied to FT-ICR MS data yielded satisfactory results to predict the plant growth time by means of a combination of the genetic algorithm with partial least squares regression (GA-PLS). The combined information of the positive and negative modes allowed the construction of the PLS regression model with a prediction error of approximately 1 week to determine the growth time of the plants.

Secondary metabolites from leaves of Manilkara subsericea (Mart.) Dubard

Background: Manilkara subsericea (Sapotaceae) is a species widely spread in the sandbanks of Restinga de Jurubatiba National Park (Rio de Janeiro, Brazil). It is commonly known as “maçaranduba”, “maçarandubinha” and “guracica”, being used in this locality as food, and timber. However, M. subsericea remains almost unexplored regarding its chemical constituents, including secondary metabolites from the leaves. Objective: Identify the chemical constituents from the leaves of M. subsericea. Materials and Methods: Leaves were macerated with ethanol (96% v/v), and dried crude ethanolic extract was sequentially washed with the organic solvents in order to obtain an ethyl acetate fraction. Substances from this fraction were identified by different techniques, such as negative-ion electrospray ionization Fourier and 1H and 13C nuclear magnetic resonance (NMR). Fresh leaves from M. subsericea were also submitted to hydrodistillation in order to obtain volatile substances, which were identified by gas chromatograph coupled to mass spectrometer. Results: NMR1H and 13C spectra allowed for the identification of the compounds myricetin, quercetin, and kaempferol from the ethyl acetate fraction. The negative-ion electrospray ionization Fourier transform ion cyclotron resonance mass spectrometry mass spectrum also revealed the presence in this fraction of a polyhydroxytriterpene acid (pomolic acid), and some flavonoids, such as quercitrin, and myricitrin. In all 34 volatile compounds were identified by gas chromatography-mass spectrometry, including monoterpenes, sesquiterpenes, and long chain hydrocarbons. Conclusion: This study describes the first reports concerning the phytochemical information about leaves from M. subsericea. SUMMARY Manilkara subsericea fruits proved to be a rich source of triterpenes. However, no phytochemical studies were carried out with leaves. Thus, we described identification of volatile substances from its essential oils, in addition to non-reported triterpene and flavonoids from this species.

Detection of Pb, Ba, and Sb in Blowfly Larvae of Porcine Tissue Contaminated with Gunshot Residue by ICP OES

Lead (Pb), barium (Ba), and antimony (Sb) concentrations were monitored in flies larvae (immature Chrysomya albiceps) contaminated with gunshot residue (GSR) from .40 caliber Taurus pistols during the period of 2 to 12 days after the death of a female pig in decomposition, during the winter, under the influence of rain and high relative humidity. The samples were also analyzed by the colorimetric test using sodium rhodizonate (Feigl-Suter reaction). It was possible to detect and quantify the three metals of interest by inductively coupled plasma-optical emission spectrometry (ICP OES), where the concentrations of all three elements kept practically constant during the putrefaction stage. Minimum ([Pb] = 382.26 μg L−1; [Ba] = 140.50 μg L−1; [Sb] = 39.18 μg L−1) and maximum ([Pb] = 522.66 μg L−1; [Ba] = 190.30 μg L−1; [Sb] = 56.14 μg L−1) concentrations were found during the third and fifth days after death, respectively. ICP OES presented higher sensitivity in metals determination when compared to the conventional colorimetric test, which showed negative result for the GSR extracts obtained from the immature Chrysomya albiceps.