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1.
Photochem Photobiol Sci ; 23(7): 1239-1249, 2024 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-38739326

RESUMO

Δ9-THC, the psychotropic cannabinoid in Cannabis sativa L., for many years has been the focus of all the pharmacological attention as the main promising principle of the plant. Recently, however, cannabidiol (CBD) has brought a sudden change in the scenario, exponentially increasing the interest in pharmacology as the main non-psychotropic cannabinoid with potential therapeutic, cosmetical and clinical applications. Although the reactivity of CBD and Δ9-THC has been considered, little attention has been paid to the possible photodegradation of these cannabinoids in the vegetal matrix and the data available in the literature are, in some cases, contradictory. The aim of the present work is to provide a characterization of the photochemical behaviour of CBD and Δ9-THC in three cannabis chemotypes, namely I (Δ9-THC 2.50%w/w), II (CBD:Δ9-THC 5.82%w/w:3.19%w/w) and III (CBD 3.02%w/w).


Assuntos
Canabidiol , Cannabis , Dronabinol , Fotólise , Canabidiol/química , Cannabis/química , Dronabinol/química
2.
Molecules ; 28(2)2023 Jan 11.
Artigo em Inglês | MEDLINE | ID: mdl-36677803

RESUMO

Rice husk (RH) in the rice industry is often air-burnt to obtain energy in the form of heat and RH ash (RHA) residue. In this work, RHA was applied as a starting material to obtain silica-supported carbon nanomaterials, resulting in a new reuse of a globally produced industrial waste product, in a circular economy approach. The preparation involves ultrasound-assisted one-pot oxidation with a sulfonitric mixture followed by wet oven treatment in a closed vessel. A study of oxidation times and RHA amount/acid volume ratio led to a solid material (nC-RHA@SiO2) and a solution containing silica-supported carbon quantum dots (CQD-RHA@SiO2). TEM analyses evidenced that nC-RHA@SiO2 consists of nanoparticle aggregates, while CQD-RHA@SiO2 are carbon-coated spherical silica nanoparticles. The presence of oxygenated carbon functional groups, highlighted by XPS analyses, makes these materials suitable for a wide range of analytical applications. As the main product, nC-RHA@SiO2 was tested for its affinity towards steroid hormones. Solid-phase extractions were carried out on environmental waters for the determination of target analytes at different concentrations (10, 50, and 200 ng L−1), achieving quantitative adsorption and recoveries (RSD < 20%, n = 3). The method was successfully employed for monitoring lake, river, and wastewater treatment plant water samples collected in Northern Italy.

3.
Int J Mol Sci ; 23(12)2022 Jun 19.
Artigo em Inglês | MEDLINE | ID: mdl-35743260

RESUMO

We evaluate the effects of the methionine-choline-deficient (MCD) diet on serum and hepatic zinc (Zn) and iron (Fe) and their relationships with matrix metalloproteinases (MMPs) and their modulators (TIMPs and RECK) as well as hepatic fatty acids using male Wistar rats fed 2-, 4- and 8-week MCD diets. Serum and hepatic Zn decrease after an 8-week MCD diet. Serum Fe increases after an 8-week MCD diet and the same occurs for hepatic Fe. An increase in hepatic MMP activity, associated with a decrease in RECK and TIMPs, is found in the MCD 8-week group. Liver Fe shows a positive correlation versus MMPs and RECK, and an inverse correlation versus TIMPs. A positive correlation is found comparing liver Zn with stearic, vaccenic and arachidonic acids, and an inverse correlation is found with linolenic and docosatetraenoic acids. An opposite trend is found between liver Fe versus these fatty acids. During NAFLD progression from steatosis to steatohepatitis, MCD rats exhibit an increase in Zn and a decrease in Fe levels both in serum and tissue associated with alterations in hepatic MMPs and their inhibitors, and fatty acids. The correlations detected between Zn and Fe versus extracellular matrix modulators and fatty acids support their potential role as therapeutic targets.


Assuntos
Hepatopatia Gordurosa não Alcoólica , Animais , Colina , Dieta , Ácidos Graxos , Ferro , Fígado , Masculino , Metionina , Camundongos , Camundongos Endogâmicos C57BL , Hepatopatia Gordurosa não Alcoólica/etiologia , Ratos , Ratos Wistar , Zinco
4.
Molecules ; 27(19)2022 Oct 05.
Artigo em Inglês | MEDLINE | ID: mdl-36235134

RESUMO

In this work, a simple, quick and efficient analytical method for determination of human and veterinary fluoroquinolone antimicrobial residues in lettuce, cucumber and spinach is developed. The procedure entails a 6 min ultrasound-assisted extraction (UAE, 3 × 2 min) in an alkaline (2% v/v NH3) aqueous solution containing Mg2+ ions (3 × 6 mL), with no need for organic solvents. The extract is submitted to cleanup on the HLB™ cartridge and the fluoroquinolones are separated and quantified by HPLC-MS/MS in a 10 min chromatographic run, using a small amount of acetonitrile in the mobile phase. The method, entirely developed in real matrices, is validated according to the updated analytical guidelines and provided suitable recoveries in the range of 67-116% and precision (RSD ≤ 20%, n = 3) at different concentrations (15, 70 and 150 ng g-1), with method quantification limits of 2-10 ng g-1. Fluoroquinolones were detected and quantified at concentrations from few to hundreds of nanograms per gram in vegetables from supermarkets, demonstrating the applicability of the method for monitoring residues of these pharmaceuticals.


Assuntos
Frutas , Verduras , Acetonitrilas/análise , Antibacterianos/análise , Cromatografia Líquida de Alta Pressão/métodos , Fluoroquinolonas/análise , Frutas/química , Humanos , Preparações Farmacêuticas/análise , Extratos Vegetais/análise , Extração em Fase Sólida/métodos , Solventes/química , Espectrometria de Massas em Tandem/métodos , Verduras/química
5.
J Nat Prod ; 84(11): 2858-2865, 2021 11 26.
Artigo em Inglês | MEDLINE | ID: mdl-34668704

RESUMO

Cannabis is a plant with an astonishing ability to biosynthesize cannabinoids, and more than 100 molecules belonging to this class have been isolated. Among them in recent years cannabidiol (CBD) has received the interest of pharmacology as the major nonpsychotropic cannabinoid with many potential clinical applications. Although the reactivity of CBD has been widely investigated, only little attention has been given to the possible photodegradation of this cannabinoid, and the data available in the literature are outdated and, in some cases, conflicting. The aim of the present work is providing a characterization of the photochemical behavior of CBD in organic solvents, through a detailed GC-MS analyses, isolation, and NMR characterization of the photoproducts obtained.


Assuntos
Canabidiol/química , Fotólise , Cromatografia Gasosa-Espectrometria de Massas , Espectroscopia de Ressonância Magnética
6.
Molecules ; 26(7)2021 Apr 03.
Artigo em Inglês | MEDLINE | ID: mdl-33916782

RESUMO

A micron-sized sorbent, Magn-Humic, has been prepared by humic acids pyrolysis onto silica-coated magnetite. The material was characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), energy dispersive spectroscopy (EDS), thermogravimetric analysis (TGA), and Brunauer, Emmett, and Teller (BET) surface area measurements and applied for simultaneous magnetic solid-phase extraction (MSPE) of glucocorticoids, estrogens, progestogens, and androgens at ng mL-1 levels from human plasma followed by high-performance liquid chromatography coupled with mass spectrometry (HPLC-MS/MS). Due to the low affinity for proteins, steroids extraction was done with no need for proteins precipitation/centrifugation. As highlighted by a design of experiments, MSPE was performed on 250 µL plasma (after 1:4 dilution) by 50 mg Magn-Humic (reusable for eight extractions) achieving quantitative recovery and satisfying clean-up. This was improved by washing (2 mL 2% v/v formic acid) prior to analytes elution by 0.5 mL 1:1 v/v methanol-acetonitrile followed by 0.5 mL methanol; eluate reduction to 0.25 mL compensated the initial sample dilution. The accuracy was assessed in certified blank fetal bovine serum and in human plasma, gaining satisfactory recovery in the range 65-122%, detection limits in the range 0.02-0.3 ng mL-1 (0.8 ng mL-1 for 17-ß-estradiol) and suitable inter-day precision (relative standard deviation (RSD) <14%, n = 3). The method was evaluated in terms of selectivity, sensitivity, matrix-effect, instrumental carry-over, and it was applied to human plasma samples.


Assuntos
Carbono/química , Fenômenos Magnéticos , Plasma/química , Microextração em Fase Sólida , Espectrometria de Massas em Tandem , Cromatografia Líquida de Alta Pressão , Humanos , Substâncias Húmicas/análise , Soroalbumina Bovina/química
7.
Angew Chem Int Ed Engl ; 60(7): 3611-3618, 2021 Feb 15.
Artigo em Inglês | MEDLINE | ID: mdl-33047446

RESUMO

Water-stable metal halide perovskites could foster tremendous progresses in several research fields where their superior optical properties can make differences. In this work we report clear evidence of water stability in a lead-free metal halide perovskite, namely DMASnBr3 , obtained by means of diffraction, optical and X-ray photoelectron spectroscopy. Such unprecedented water-stability has been applied to promote photocatalysis in aqueous medium, in particular by devising a novel composite material by coupling DMASnBr3 to g-C3 N4 , taking advantage from the combination of their optimal photophysical properties. The prepared composites provide an impressive hydrogen evolution rate >1700 µmol g-1 h-1 generated by the synergistic activity of the two composite costituents. DFT calculations provide insight into this enhancement deriving it from the favorable alignment of interfacial energy levels of DMASnBr3 and g-C3 N4 . The demonstration of an efficient photocatalytic activity for a composite based on lead-free metal halide perovskite in water paves the way to a new class of light-driven catalysts working in aqueous environments.

8.
Anal Chem ; 91(15): 10110-10115, 2019 08 06.
Artigo em Inglês | MEDLINE | ID: mdl-31251032

RESUMO

The parameters characterizing the formation of complexes with albumin (in particular, human serum albumin (HSA)) are fundamental for the characterization of a drug for commercialization purposes and for the determination of common pharmacokinetic parameters. Electrochemical methods appear particularly attractive for the determination of the complexation constant, complex stoichiometry, and percentage of free/bound drug, due to the ease of operation and the wide availability. In this article, we propose an electrochemical method based on differential pulse voltammetry for the determination of albumin-drug interaction parameters, including the replacement of the drug-albumin adduct by a competitive compound, sulfanilamide. The formation of either single or multiple complexes between the considered drug and albumin has been considered. Typically, the method operates with a glassy carbon electrode in NaCl 0.9% as the supporting electrolyte.


Assuntos
Albuminas/metabolismo , Eletroquímica , Eletrodos , Sulfanilamida/metabolismo , Albuminas/química , Animais , Bovinos , Humanos , Concentração de Íons de Hidrogênio , Ligação Proteica , Ovinos , Sulfanilamida/química
9.
Sensors (Basel) ; 19(23)2019 Nov 28.
Artigo em Inglês | MEDLINE | ID: mdl-31795303

RESUMO

Highly sensitive plasmonic optical fiber platforms combined with receptors have been recently used to obtain selective sensors. A low-cost configuration can be obtained exploiting a D-shaped plastic optical fiber covered with a multilayer sensing surface. The multilayer consists of a gold film, functionalized with a specific receptor, where the surface plasmon resonance (SPR) occurs. The signal is produced by the refractive index variation occurring as a consequence of the receptor-to analyte binding. In this work, a selective sensor for copper(II) detection in drinking water, exploiting a self-assembled monolayer (SAM) of d,l-penicillamine as the sensing layer, has been developed and tested. Different concentrations of copper(II) in NaCl 0.1 M solutions at different pH values and in a real matrix (drinking water) have been considered. The results show that the sensor is able to sense copper(II) at concentrations ranging from 4 × 10-6 M to 2 × 10-4 M. The use of this optical chemical sensor is a very attractive perspective for fast, in situ and low-cost detection of Cu(II) in drinking water for human health concerns. Furthermore, the possibility of remote control is feasible as well, because optical fibers are employed.

10.
Anal Bioanal Chem ; 410(29): 7635-7643, 2018 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-30255326

RESUMO

Silica-supported pyrolyzed lignin (pLG@silica) was investigated as a solid sorbent for the pre-concentration of rare earth elements (REE) from natural waters followed by inductively coupled plasma mass spectrometry (ICP-MS) analysis. The carbon-based material was easily prepared by pyrolytic treatment of lignin at 600 °C after its adsorption onto silica micro-particles. pLG@silica was characterized by scanning electron microscopy (SEM), surface area measurements (BET method), thermogravimetric analysis (TGA), Fourier transform infrared spectroscopy (FT-IR), point of zero charge measurement, and X-ray photoelectron spectroscopy (XPS). The as-prepared material (50 mg) was tested as fixed-bed sorbent for the solid-phase extraction (SPE) of tap, river, and sea water samples spiked with REE in the 10-150 ng L-1 range, followed by ICP-MS analysis. A quantitative adsorption was observed for all REE with recoveries in the range of 72-118%. A suitable inter-day precision (RSDs 5-12%, n = 3) was obtained. Sample volumes up to 250 mL provided enrichment factors up to 100. The method detection and quantification limits (MDLs and MQLs) were in the range of 0.4-0.6 ng L-1 and 1-2 ng L-1, respectively. The batch-to-batch reproducibility was verified on four pLG@silica independent preparations. As remarkable advantages, pLG@silica proved to be of easy preparation using a waste material, inexpensive, and reusable for at least 20 SPE cycles.

11.
Anal Bioanal Chem ; 409(28): 6709-6718, 2017 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-29071365

RESUMO

This work shows a novel analytical method for the simultaneous extraction of environmental emerging contaminants as benzenesulfonamides (BSAs), benzotriazoles (BTRs), and benzothiazoles (BTs) from water samples. Pristine multi-walled carbon nanotubes (MWCNTs), not yet tested for such analytes, are here employed as the sorbent phase for dispersive solid-phase extraction (d-SPE) followed by high-performance liquid chromatography/electrospray ionization tandem mass spectrometry (HPLC-HESI-MS/MS). Quantitative sorption is gained by treating 50 mL sample with 100 mg MWCNTs (2 g L-1) in 10 min contact, both in tap and raw river water. After sorption, the analytes are quantitatively desorbed by microwaves (20 min, 160 °C, 250 W) by using 5 mL methanol-ethylacetate-acetic acid (10:70:20, v/v), according to the indications obtained by a chemometric study. The extract is reduced to small volume before analysis, thus reaching overall enrichment factors up to 400. Recovery of the entire procedure, evaluated on tap and surface water samples spiked with 0.1/0.5-50 µg L-1 of each analyte, was in the range 70-116%, with excellent inter-day precision (RSD < 7%). Selectivity and firm analyte identification were assured by MRM detection, and suitable sensitivity was obtained for determination of these pollutants in actual matrices (experimental MDLs 30-170 ng L-1). The proposed analytical method was applied to the analysis of surface water samples, containing concentrations of these contaminants ranging from 100 ng L-1 to 2 µg L-1. Pristine MWCNTs proved to be a valid alternative to other commercial sorbents, both in terms of cost and sorption capacity. Graphical abstract Determination of benzenesulfonamides, benzotriazoles, and benzothiazoles in environmental waters by dispersive multi-walled carbon nanotube extraction prior HPLC-MS.

12.
Int J Legal Med ; 130(4): 1045-1052, 2016 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-27179646

RESUMO

The identification and quantification of metallic residues produced by gunshots, called gunshot residues (GSR), provide crucial elements in forensic investigations. The research has been largely focused on their collection onto the hands of suspected shooters, but the method is often burdened by risks of contamination. This research was focused on the possibility of sampling GSR trapped inside the nasal mucus of consenting shooters. Samples of the nasal mucus of "blank" control subjects and shooters were chemically analysed by Instrumental Neutron Activation Analysis (INAA), for residues of antimony (Sb) and barium (Ba), while lead (Pb) was excluded as ubiquitously environmental contaminant and due to high instrumental quantification limit (IQL) of INAA for this element. Shots were fired using two types of weapons (pistols and revolvers) and different firing sequences. The mucus was sampled at different times: immediately after the shots, after 30-60-120 and 180 min. Different amounts of Sb and Ba were detected between controls and shooters, witnessing the ability of the nasal mucus to retain GSR at concentrations significantly different even from the highest basal levels. Moreover, in order to simulate actual cases, nasal mucus from five groups of shooters was sampled after different shots with the same weapon and cartridges, immediately and after 1, 3, 12, and 24 h. The highest values were always found in the first 3 h from firing, for both weapons. Interestingly, for all the weapons, significant Sb and Ba concentrations were also found up to 12 h after firing, contrary to what occurs on hands, even though a progressive decrease was detected, with values below the detection threshold only after 24 h, thus demonstrating that GSR are persistent in nasal mucus. These first results proving that both Sb and Ba were qualitatively detectable in the nasal mucus of shooters indicate that the chemical analysis of the nasal mucus of suspected shooters may represent a promising tool in the forensic field since it is less burdened by problems related to sampling or contamination than the usual sampling on hand, providing that ammunitions employed contain Ba and Sb.


Assuntos
Antimônio/análise , Bário/análise , Armas de Fogo , Chumbo/análise , Muco/química , Mucosa Nasal/química , Estudos de Casos e Controles , Humanos
13.
Orig Life Evol Biosph ; 46(2-3): 223-31, 2016 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-26680445

RESUMO

Despite its importance in the prebiotic and biochemical fields, a complete theoretical study of the formation of hexamethylenetetramine (HMT) starting from its precursors ammonia and formaldehyde has not received due considerations in the literature with regard to the thermodynamic feasibility of many of the mechanistically proposed intermediates in its formation. Most of the studies in this area have been mostly concerned with the initial steps of the reaction between formaldehyde and ammonia, while poor attention is dedicated to successive steps. In this article, different results from published literature were critically considered and the most probable hypothesis regarding the mechanism of HMT formation is discussed on the basis of B3LYP calculations of free energies.


Assuntos
Amônia/química , Formaldeído/química , Metenamina/síntese química , Origem da Vida , Evolução Química , Modelos Químicos , Teoria Quântica , Termodinâmica
14.
Biochim Biophys Acta ; 1834(1): 197-204, 2013 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-22999980

RESUMO

Human prolidase, the enzyme responsible for the hydrolysis of the Xaa-Pro/Hyp peptide bonds, is a key player in the recycling of imino acids during the final stage of protein catabolism and extracellular matrix remodeling. Its metal active site composition corresponding to the maximal catalytic activity is still unknown, although prolidase function is of increasing interest due to the link with carcinogenesis and mutations in prolidase gene cause a severe connective tissue disorder. Here, using EPR and ICP-MS on human recombinant prolidase produced in Escherichia coli (hRecProl), the Mn(II) ion organized in a dinuclear Mn(II)-Mn(II) center was identified as the protein cofactor. Furthermore, thermal denaturation, CD/fluorescence spectroscopy and limited proteolysis revealed that the Mn(II) is required for the proper protein folding and that a protein conformational modification is needed in the transition from apo- to Mn(II)loaded-enzyme. The collected data provided a better knowledge of the human holo-prolidase and, although limited to the recombinant enzyme, the exact identity and organization of the metal cofactor as well as the conformational change required for activity were proven.


Assuntos
Dipeptidases/química , Precursores Enzimáticos/química , Manganês/química , Espectrometria de Fluorescência , Catálise , Domínio Catalítico , Dicroísmo Circular , Dipeptidases/metabolismo , Precursores Enzimáticos/metabolismo , Humanos , Hidrólise , Manganês/metabolismo , Desnaturação Proteica , Dobramento de Proteína
15.
Photochem Photobiol Sci ; 13(10): 1410-9, 2014 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-25051203

RESUMO

This work presents a systematic study of cellulose (CLS) as a sacrificial biomass for photocatalytic H2 evolution from water. The idea is indeed to couple a largely available and not expensive biomass, and water, with a renewable energy like solar radiation. An aqueous CLS suspension irradiated either at 366 nm (UV-A) or under sunlight in the presence of Pt/TiO2 behaves as a H2 evolving system. The effects of irradiation time, catalyst and CLS concentrations, pH and water salinity are studied. Addition of CLS to the sample significantly improved H2 evolution from water splitting, with yields up to ten fold higher than those observed in neat water. The mechanism of the photocatalytic process relies on the TiO2-mediated CLS hydrolysis, under irradiation. The polysaccharide depolymerisation generates water-soluble species and intermediates, among them 5-hydroxymethylfurfural (HMF) was identified. These intermediates are readily oxidized following the glucose photoreforming, thus enhancing water hydrogen ion reduction to give gas-phase H2. The formation of "colored" by-products from HMF self-polymerization involves a sort of "in situ dye sensitization" that allows an effective photoreaction even under solar light. The procedure is evaluated and successfully extended on cellulosic biomasses, i.e. rice husk and alfalfa (Medicago sativa) stems, not previously investigated for this application.


Assuntos
Celulose/química , Hidrogênio/química , Hidrogênio/efeitos da radiação , Processos Fotoquímicos , Luz Solar , Água/química , Biomassa , Catálise/efeitos da radiação , Suspensões
16.
Anal Bioanal Chem ; 406(15): 3657-65, 2014 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-24652153

RESUMO

This is the first report on the analytical application of multiwalled carbon nanotubes (MWCNTs) as solid-phase extraction (SPE) sorbents for determination in surface waters, at the nanograms per litre level, of perfluorooctanoic acid (PFOA) and perfluorooctane sulfonate (PFOS), the two predominant contaminants among the perfluorinated compounds detected. After the preconcentration step, the quantification was achieved by ultraperformance liquid chromatography-electrospray ionization mass spectrometry. To increase the extraction efficiency towards these amphiphilic compounds, MWCNTs were derivatized with amino-terminated alkyl chains, thus producing a mixed-mode material (MWCNT-R-NH2) combining hydrophobic affinity and anion-exchange properties. Experiments with distilled, tap and river water (pH 3) spiked at different concentrations (10, 15, 30, 100, 200 and 500 ng L(-1)) provided absolute recoveries in the range 71-102% (n = 3, relative standard deviations less than 10%). Analytes were eluted in a single fraction with 6 mL methanol (3 × 10(-4) M NaOH). The within-laboratory reproducibility of the MWCNT-R-NH2 SPE sorbent was evaluated with raw river water, and relative standard deviations less than 15% were obtained (n = 4). Preconcentration factors up to 125 (500-mL sample) made it possible to quantify PFOA and PFOS at low nanograms per litre levels in naturally contaminated river water. The method quantification limits of 10 ng L(-1) for PFOA and 15 ng L(-1) for PFOS were well below the advisory levels for drinking and surface waters. Comparison with non-derivatized MWCNTs highlighted the role of functionalization in improving the adsorption affinity towards these contaminants. MWCNT-R-NH2 maintained their extraction capability for at least eight repeated adsorption/desorption cycles.

17.
Artigo em Inglês | MEDLINE | ID: mdl-39014139

RESUMO

The occurrence of sex steroid hormones, viz. oestrogens and progestins, in aquatic ecosystems is of global concern due to their role as endocrine disrupting chemicals, even at low concentration (µg L-1 or less). Thus, it is essential to monitor these organic pollutants to get a realistic picture of their presence and to control their contamination levels in environmental water bodies. In this respect, we have explored the use of self-prepared polymeric films as novel sorptive phase for the microextraction of 17ß-estradiol, 17α-ethinylestradiol, estrone, progesterone, medroxyprogesterone acetate and hydroxyprogesterone. The thin film microextraction procedure has been developed, evaluating different film compositions, sample volumes and elution conditions to recover the sorbed analytes. The overall method provides good reproducibility (RSD < 12%) and recoveries higher than 60%. The final method has been applied to environmental monitoring in surface waters (river and lake samples) and urban wastewater treatment plant effluents and influents from Northern Italy, to get a contamination snapshot of this highly urbanized area.

18.
J Forensic Sci ; 69(3): 1035-1044, 2024 May.
Artigo em Inglês | MEDLINE | ID: mdl-38332695

RESUMO

Memory effect in firearms that is, the possibility for a weapon to release inorganic particles whose elemental composition depends on its entire shooting history, is responsible for most of the interpretation difficulties encountered in forensic gunshot residue analysis. The presence of residues chemically inconsistent with the last discharged round, the creation of particles having unusual elemental profiles, and the dependence of residue population composition on the collection point are all manifestations of memory effect. The experimental results reported in this paper highlight the ineffectiveness of a wide number of gun cleaning procedures in reducing memory effect. Moreover, the common alternative of discharging batches of rounds having a "new" primer mixture does not fully eliminate the possibility to recover "old" residues at least from the shooter's hands. Two brand new pistols and ammunition having lead-based, leadless and heavy metal free primers were used. Specimens, collected both from the shooters' hands and from cotton targets set nearby the gun muzzle, were analyzed by SEM-EDS and by ICP-OES. After discharging 10's of new ammunitions, the number of old residues ejected from the gun muzzle indeed showed an asymptotic decrease to zero. In spite of this, the number of old residues recovered from the shooter's hands did not follow any predictable trend. These different behaviors suggest that all internal components of a gun, and not just the barrel, play a role in memory effect.

19.
Anal Chim Acta ; 1288: 342151, 2024 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-38220285

RESUMO

BACKGROUND: Synthetic cannabinoids (SCs) are a broad class of illicit drugs that are classified according to the chemical structure of the aromatic core that they present (i.e., indole, imidazole, pyrrole) and their detection is still a challenge, despite their widespread diffusion. The identification of a specific class of SC in complex matrices, such as real samples with a rapid, economic analytical device useable directly in the field, is highly desirable, as it can provide immediate and reliable information that eventually addresses more targeted analyses. RESULTS: The present paper proposes a Molecularly Imprinted Polymer (MIP)-based voltammetric sensor for the rapid and selective detection of indazole-type SCs. In this context, a polyacrylate-based MIP was used to functionalize a Pt electrode. The MIP composition was optimized through a Design of Experiments approach, and for the sake of safety, a non-psychotropic compound structurally related to the selected SCs was employed as the template in the MIP formulation. A complete characterization of the electrochemical behavior of the selected SCs was performed, and differential pulse voltammetry (DPV) in acetonitrile/lithium perchlorate 0.1 M was the technique applied for their quantification. LOD around 0.01 mM and linearity up to 0.8 mM were found. Comparison with the non-imprinted (NIP) modified and bare electrodes showed better selectivity and reproducibility of the MIP-based sensor. Recovery tests (in the 70-115 % range) were performed on simulated pills and smoking mixtures to test the reliability of the proposed method. SIGNIFICANCE: The method proposed allows the identification and quantification of indazole-based SCs as a class in complex matrices. Due to the selectivity of the obtained device, no clean-up of the sample before analyses is needed. For the same reason, the interference of cutting substances and natural cannabinoids was negligible.


Assuntos
Canabinoides , Impressão Molecular , Polímeros Molecularmente Impressos , Polímeros/química , Reprodutibilidade dos Testes , Aminoácidos , Impressão Molecular/métodos , Técnicas Eletroquímicas/métodos , Eletrodos , Limite de Detecção
20.
Anal Chim Acta ; 1308: 342658, 2024 Jun 15.
Artigo em Inglês | MEDLINE | ID: mdl-38740458

RESUMO

BACKGROUND: The environmental impact of sample preparation should be minimized through simplification of the procedures and the use of natural, renewable and/or reusable materials. In such scenario, thin-film microextraction fulfils the former criteria, as it enables few steps and miniaturization, thus small amount of extraction phase. At the same time, the use of sorbents such as biochars obtained from biomass waste is even more promoted due to their availability at low cost and increased life-cycle in a circular economy vision. However, it is not always easy to combine these criteria in sample preparation. RESULTS: A thin film microextraction was developed for the determination of steroids in aqueous samples, entailing a membrane made of cellulose triacetate and a wood-derived biochar (Nuchar®) as carbon precursor. Different characterization techniques showed the successful preparation, whereas the sorption kinetics experiments demonstrated that biochar is responsible for the extraction with the polymer acting as a smart support. After a study about membranes' composition in terms of biochar amounts (4 %, 10 %, 16 % wt) and type of synthesis set up, the ceramic 3D-mold was selected, achieving reproducible and ready-to-use membranes with composition fixed as 10 %. Different elution conditions, viz. type and time of agitation, type, composition and volume of eluent, were evaluated. The final microextraction followed by HPLC-MS/MS quantification was successfully validated in river and wastewater treatment plant effluent samples in terms of accuracy (R% 64-123 %, RSD<19 % in river; R% 61-118 %, RSD <18 % in effluent, n = 4), sensitivity (MQLs 0.2-8.5 ng L-1) and robustness. SIGNIFICANCE: This novel biochar-based polymeric film proved to be a valid and sustainable sorbent, in terms of extraction capability, ease of preparation and greenness. By comparison with literature and the greenness evaluation with the most recent metric tools, this method expands the potential applicability of the thin-film microextraction and opens up innovative scenarios for sustainable procedures entailing the use of biochars entrapped in bio-polymers.


Assuntos
Carvão Vegetal , Polímeros , Águas Residuárias , Poluentes Químicos da Água , Carvão Vegetal/química , Águas Residuárias/análise , Águas Residuárias/química , Poluentes Químicos da Água/análise , Poluentes Químicos da Água/isolamento & purificação , Polímeros/química , Adsorção , Esteroides/análise , Esteroides/química , Esteroides/isolamento & purificação , Microextração em Fase Sólida/métodos
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