cometadata/datacite-titles-descriptions-related-identifiers huggingface dataset:
DOI: 10.6084/m9.figshare.14304080.v1
title: X-ray Scattering and Chemometrics as Tools to Assist in the Identification of Gunshot Residues by Wavelength Dispersive X-ray Fluorescence Spectrometry

description: Wavelength dispersion X-ray fluorescence spectrometry (WDXRF) is a non-destructive technique and therefore attractive for gunshot residues (GSR) analysis. It is well known for determination of inorganic constituents of samples. However, X-ray scattering region spectral data is not commonly used, although it may provide information about organic constituents and their interactions. This work employed X-ray scattering region and inorganic elements spectral data for a better characterization of GSR. Swabs containing residues collected from the hand of people who fired (shooters group) and also from the hands of people which did not fire (control group) with guns were analyzed directly by the WDXRF. Brake pad and people who perform activities that favor the accumulation of characteristic elements of GSR on their hands were chosen to compose the control group. Principal components analysis (PCA) discriminated the GSR according to the firearm/cartridge used. However, similar GSR clustering did not occur without X-ray scatter data, showing the importance of X-ray scattering spectrum for GSR evaluation. The k-nearest neighbors (k-NN) method correctly classified all samples from shooters and control groups, employing from 1 to 5 nearest neighbors. No anomalous behavior was detected by PCA and hierarchical cluster analysis (HCA).
DOI: 10.6084/m9.figshare.14304078.v1
title: Optimization of Methodology for Determination of Inorganic Chromium Species in Sewage Sludge Samples by HPLC-ICP-MS/MS

description: This study developed a methodology for extracting and speciating CrIII and CrVI in sewage sludge by high performance liquid chromatography, inductively coupled plasma tandem mass spectrometry (HPLC-ICP-MS/MS). The optimal procedure was solid-liquid extraction in a water bath with stirring at 50 °C for 16 h and 50 mmol L−1 ethylenediaminetetraacetic acid (EDTA) extraction phase at pH 9.5. In the validated method, the recovery in the fortification experiment was greater than 70% and the relative standard deviation was less than 7%. Speciation analyses showed that all CrVI was spontaneously reduced to CrIII in the sludge sample. The limits of detection and quantification were 0.060 and 0.20 µg L−1, respectively, and the analyses of CrIII by means of ICP-MS/MS were linear from 0.20 to 50 µg L−1. The extraction efficiency of Cr specie in this validated method improved from 4.09 to 53.3% compared to the EPA 1311 method. The methodology was successfully applied to quantify CrIII in a sludge sample with a lower concentration than that established by European legislation 80568/4225/91.
DOI: 10.6084/m9.figshare.14304075.v1
title: Development of a First-Order Derivative UV Spectrophotometric Method for the Assay and Solubility Evaluation of Lamotrigine and Nicotinamide Cocrystals

description: Pharmaceutical cocrystals are composed of a drug and a coformer and are currently gaining attention due to their possibility of improving drug solubility. Quantitative determination of cocrystals is usually carried out by liquid chromatography method, but an alternative for the same is derivative UV spectrophotometry. Cocrystals of lamotrigine (LAM) were formed with nicotinamide (NIC) in order to improve the solubility of LAM. The aim of this study was to develop and validate a simple, low-cost, environment friendly, first-order derivative spectrophotometric method for simultaneous determination of LAM and NIC in cocrystals. Determination of LAM and NIC was performed at 244.4 and 271.6 nm, respectively. The method was accurate with recovery values of 98.21-101.52%, and precise (relative standard deviation (RSD) &lt; 1.88%). Robustness evaluated by Plackett-Burman design showed no significant influence of the factors (pH, scanning speed, and sonication time) on LAM and NIC assays. The developed method was compared with a high performance liquid chromatography (HPLC) method and applied to study the cocrystal stoichiometry and solubility. The results indicated a molar ratio of 1:1 and that the cocrystal is more soluble than the drug. This study demonstrated that the first-order derivative method is feasible for drug and coformer determination in cocrystals and is a suitable alternative to chromatographic methods.
DOI: 10.6084/m9.figshare.14304074.v1
title: Evaluation of Dog Food Authenticity through Lipid Profile Using GC-FID and ESI-MS

description: Considering the increasing number of low cost vegetable oil product adulterations, it is necessary to assess the authenticity of the lipid sources used in the dog food manufacture, consequently different brands and classifications of feed were analyzed to verify the product authenticity by gas chromatography (GC) with flame ionization detector (FID) and by electrospray ionization mass spectrometry (ESI-MS). Fatty acid (FA) composition analysis was performed to compare the FAs amount in samples with the respective guarantee levels stated by the manufacturers on its product label. Gas chromatography with flame ionization detector (GC-FID) results for omega-3 and 6 percentages are within the limits presented by each manufacturer, while the timnodonic + cervonic acids amount information presented on feed sample labels is not in accordance with GC-FID results. Consequently, the samples were analyzed by ESI-MS, the results exposed the chicken oil presence in the feed and eicosapentaenoic (EPA) + docosahexaenoic (DHA) acids absence, since no lipid profiles similar to fish oils or triacylglycerols (TAGs) containing these two FAs were found. Thus, the information presented on labels are in disagreement with the results obtained both by GC-FID FA composition analysis and by ESI-MS lipid profile analysis. Principal component analysis (PCA) confirmed that the main contribution was from FAs found by GC-FID.
DOI: 10.6084/m9.figshare.14304071.v1
title: Calibration Strategies Applied to Laser-Induced Breakdown Spectroscopy: A Critical Review of Advances and Challenges

description: Over the years, laser-induced breakdown spectroscopy (LIBS) has been reported in the literature as an alternative to traditional methods of analysis, becoming well established among spectroanalytical techniques. LIBS is a technique widely used for qualitative approaches; however, it is necessary considerable effort for use in quantitative analysis, mainly due to severe matrix effects. These limitations make it difficult to broaden the application of LIBS in quantitative analysis. In this sense, this review discusses recent advances in calibration strategies applied in LIBS for minimizing matrix effects and enabling determination with satisfactory accuracy and precision. Applications, advantages, and limitations of the calibration strategies, such as matrix-matching calibration (MMC), internal standardization (IS), standard addition (SA), multi-energy calibration (MEC), one-point gravimetric standard addition (OP GSA), one-point and multi-line calibration (OP MLC), slope ratio calibration (SRC), two-point calibration transfer (TP CT), single-sample calibration (SSC), multiple linear regression (MLR), principal component regression (PCR), partial least squares (PLS) and artificial neural networks (ANN) are discussed.
DOI: 10.6084/m9.figshare.14304069.v1
title: Blue-Emitting MWO4:Tm3+ (M: Sr, Ba) Phosphors Prepared by Coprecipitation Method at Room Temperature

description: MWO4 host matrices (M: Sr, Ba) doped with different Tm3+ concentrations (0.02, 0.04, 0.06, 0.08 and 0.10 mol%) have been successfully prepared by the coprecipitation method at room temperature. The as-prepared nanophosphors were characterized by infrared spectroscopy showing intense absorption bands in the range of 700-1000 cm-1 attributed to the symmetrical and asymmetrical stretching vibrations (ν) of the tetrahedral [WO4]2- group. The X-ray diffraction (XRD) measurements reveal the tetragonal scheelite phase with the I41/a (No. 88) space group. The emission spectra of the MWO4:Tm3+ materials are dominated by the highest intensity narrow band of the intraconfigurational 1D2 → 3F4 transitions in the blue region (ca. 456 nm) arising from the Tm3+ ions. Additional low-intensity emission bands originated from the 1G4 → 3H6 (ca. 475 nm), 1G4 → 3F4 (660 nm) and 3H4 → 3H6 (700 nm) transitions are also observed. These optical results indicate that the materials can be used as an alternative to blue-emitting markers.
DOI: 10.6084/m9.figshare.14304066.v1
title: Synthesis of 1,2,3-Triazole Derivatives of Hydnocarpic Acid Isolated from Carpotroche brasiliensis Seed Oil and Evaluation of Antiproliferative Activity

description: Carpotroche brasiliensis is a tree native to Brazil, belonging to the family Flacurtiaceae, whose seeds contain a group of cyclopentenyl fatty acids: gorlic (12%), chaulmugric (27%), and hydnocarpic (48.7%). These compounds are considered the main therapeutic agents in the treatment of leprosy. In the present study, a series of novel triazole compounds were obtained by conjugation between hydnocarpic acid and functionalized azides via copper(I)-catalyzed azide-alkyne cycloaddition reaction (CuAAC). Hydnocarpic acid and its derivatives were tested against estrogen-positive breast carcinoma (MCF-7), hepatocellular carcinoma (HepG2), and non-small cell lung cancer (A549) cell lines. The (R)-(1-(pyridin-2-ylmethyl)-1H-1,2,3-triazol-4-yl)methyl-11-(cyclopent-2-en-1-yl)undecanoate (8) displayed promising antiproliferative activity against A549 cells. We demonstrated that this compound selectively inhibited the viability of A549 cell cultures. Furthermore, compound 8 inhibited the clonogenic capacity of A549 cells, and this effect was associated to its ability to inhibit cell cycle progression at G1 phase. These findings indicate that 8 is a promising antitumor agent on A549 cells and support further studies to evaluate the molecular mechanisms underlying its antiproliferative activity. In addition, hydnocarpic acid should be considered as a promising chemical prototype to obtain novel antineoplastic agents.
DOI: 10.6084/m9.figshare.14304065.v1
title: A Straightforward Synthesis of Enantiopure (1S,2R)-Ephenamine

description: An enantioselective six-step synthesis of (1S,2R)-ephenamine starting from readily available chiral amino acid is disclosed presenting 26% overall yield and high optical purity. The use of chiral phenylglycine as starting material was also studied and did not present satisfactory results due to a very sensitive a-carbonyl/benzylic stereogenic center that, in our hands, led to racemization.
DOI: 10.6084/m9.figshare.14304062.v1
title: Photoluminescent Investigation of the Doping Site of Eu3+-Doped [Zn3(BTC)2·12H2O] Metal-Organic Framework Prepared by Microwave-Assisted Hydrothermal Synthesis

description: The [Zn3(BTC)2·12H2O] (BTC = 1,3,5-tricarboxylate) metal-organic framework (MOF) was successfully synthesized using a microwave-assisted hydrothermal synthesis technique, which allowed for significantly decreased reaction time compared to the production of the same compound via conventional heating. In situ doping with Eu3+ ions at concentrations ranging from 1.0 to 5.0 mol% produced doped materials whose emission ranged from blue to red color. The Eu3+ spectroscopic properties were used to study the incorporation of the dopant into the structure of [Zn3(BTC)2·12H2O], even at very low concentrations. These experiments confirmed the usefulness of this ion as a luminescent probe, as it permitted the identification of small variations in structure not perceptible by X-ray diffraction. The variation in the coordination environment induced by increases in doping percentage was analyzed by evaluating changes in the characteristic Eu3+ excitation and emission profiles, using them to calculate luminescence lifetimes, experimental intensity parameters Ωλ (λ: 2 and 4) as well as the intrinsic quantum yield (QEu+3Eu+3) of the 5D0 emitting level of each doped MOF. The excitation and luminescence spectra show that intramolecular energy transfer from the BTC linker to Eu3+ ion, and we could observe the emission color tuning originated from the emissions of the BTC ligand and Eu3+ ion.
DOI: 10.6084/m9.figshare.14304059.v1
title: Synergistic Supramolecular Effect on the Electro-Oxidation of Biological Relevant Molecules: A Novel Sensor for Simultaneous Determination of Epinephrine and Uric Acid in Human Urine Using MWCNT and a Copper(II) Complex

description: In this paper a novel supramolecular strategy to improve the efficiency of a voltammetric sensor to determine two biologically relevant molecules (epinephrine (EP) and uric acid (UA)) is presented. The strategy is based on the use of a glassy carbon electrode modified with a copper(II) complex ([Cu(H2dimpy)Cl]PF6) adsorbed on multi-walled carbon nanotubes (MWCNTs). The [Cu(H2dimpy)Cl]PF6/MWCNT composite-supported electrode was characterized by electrochemical impedance spectroscopy, scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS). The electrocatalytic oxidation of EP and UA using the sensor was investigated by cyclic voltammetry and square wave voltammetry. Under optimized conditions, voltammetric peak currents showed a linear response for the EP and UA concentrations in the ranges 0.5-159.2 and 0.2-58.5 µmol L−1, whereas the limits of detection were 0.2 and 0.05 µmol L−1, respectively. The sensor was successfully applied in the selective and simultaneous determination of EP and UA in human urine samples. Thus, our results showed that the supramolecular strategy was successful to build an efficient sensor for simultaneous detection of these molecules in biological samples.
DOI: 10.6084/m9.figshare.14304057.v1
title: Sunlight-Driven Dehydrogenative Oxidation Photocatalysis by a Mononuclear Complex Acting as both Chromophore and Catalyst

description: Under simulated solar irradiation in the visible spectral region, the catalytically active RuIV-oxo species [Ru(O)(bpy)(tppz)]2+ (tppz = tetrapyridylpyrazine, a strongly π-accepting tridentate N, N, N-ligand) is produced directly from a single metal-to-ligand charge-transfer (MLCT) photoexcitation of the resting RuII-aquo complex [Ru(H2O)(bpy)(tppz)]2+ in aqueous media containing an electron acceptor. This photoinduced path to 2-electron/2-proton activation of a mononuclear catalyst (i.e., without a paired chromophoric unit) is enabled by the thermodynamic instability of the intermediate RuIII-hydroxo species [Ru(OH)(bpy)(tppz)]2+, which promptly disproportionates into the RuIV-oxo and RuII-aquo states as electrochemically observed by cyclic and pulse voltammetries in a wide range of pH. The proton-coupled multielectron photocatalytic capability of the complex in neutral aqueous solutions, at room conditions, was demonstrated through the dehydrogenative oxidation of benzyl alcohol into benzaldehyde with a product selectivity of about 100%. The performance of this mononuclear complex acting as chromophore/catalyst is comparable to that of the previously reported dinuclear complex [(tpy)Ru(tppz)Ru(HxO)(bpy)]4+. In addition to the characterization of redox and spectroscopic properties for the [Ru(L)(bpy)(tppz)]n+ derivatives with L = Cl- or HxO, structural analysis of the precursor chloro complex [RuCl(bpy)(tppz)](PF6) was also performed by single-crystal X-ray diffraction in this work.
DOI: 10.6084/m9.figshare.14304054.v1
title: Where’s the Spin? A DFT Study of Mixed-Valence Cyanide-Bridged Ruthenium Polypyridines

description: This article discusses the use of density functional theory (DFT) calculations in classifying and characterizing bimetallic ruthenium mixed-valence systems in terms of their electronic localization/delocalization degree. A standard B3LYP/LanL2DZ methodology including integral equation formalism-polarizable continuum model (IEF-PCM) solvent model is evaluated for a set of 16 non-symmetric mixed-valence cyanide-bridged ruthenium polypyridines. This procedure reproduces well the features of the observed electronic and vibrational spectra, with better agreement for the more delocalized systems, and therefore provides an appropriate description of the electronic structures. Computed spin densities support class II or class III Robin-Day assignments and allow to quantify the electronic delocalization degree. The applied methodology yields good results due to the nature of the systems explored, which display a strong electronic coupling promoted by the cyanide-bridge and a lack of strong specific solvation effects. This procedure is not only useful in the study of ground state mixed-valence systems, but also provides a powerful insight into photoinduced mixed-valence excited states of related complexes.
DOI: 10.6084/m9.figshare.14304051.v1
title: Application of Nickel Ferrite Nanoparticles in Adsorption of Amoxicillin Antibiotic

description: According to the World Health Organization, amoxicillin (AMX) is the most widely consumed antibiotic in the world. Consequently, there is great interest in the development of new technologies that allow the removal of this type of contaminant, as exposure to antibiotic residues can cause a variety of adverse effects, such as toxicity and antimicrobial resistance. In this work, AMX adsorption from aqueous solution was investigated using nickel ferrite nanoparticles. The nanoadsorbents were prepared by the coprecipitation method, annealed at 300 to 700 °C, and characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), Mössbauer spectroscopy (ME) and vibratory sample magnetometry (VSM). Nanoparticle size, pH and temperature were found to significantly affect the amount of adsorbed AMX. The pseudo-second order kinetic model described the adsorption process and the adsorption isotherm fitted to the Freundlich model. AMX adsorption capacity was 104-45 mg g−1 (miligram of AMX per gram of ferrite) for ferrite annealed at 300-700 °C, respectively. The nanoadsorbents employed showed higher AMX removal efficiency when compared to other iron oxides. Moreover, the good reuse results obtained showed their great potential for antibiotic removal by adsorption.
DOI: 10.6084/m9.figshare.14304050.v1
title: Zeolite-SPION Nanocomposite for Ammonium and Heavy Metals Removal from Wastewater

description: Minimizing the emission of industrial effluents and realizing the recovery/extraction of key elements such as the rare earths from low concentration solutions, or during water decontamination processes, are some of the biggest challenges of modern society. Accordingly, the preparation and characterization of a low cost recyclable and reusable superparamagnetic iron oxide nanoparticles (SPION)/zeolite nanocomposite (Zmag) is described, and the possibility of their use for removal of heavy metals and ammonium/ammonia is discussed, generating water whose quality is in compliance with the more strict modern environmental laws. Such materials are suitable for realization of a more efficient dispersion method for adsorption in combination with magnetically aided concentration/separation processes for removal of contaminants. In fact, Zmag was shown to efficiently remove PbII and HgII, as well as NH4+ from water, generating effluents that can be directly disposed in water bodies according to the current environmental law requirements, as stated by EPA (North America Environmental Protection Agency). That nanocomposite material has a competitive production cost and allowed a cutback in the nitrogen (NH3) content from 300 mg L-1 (diluted slurry source) to less than 36 mg L-1. Furthermore, Zmag demonstrated high capacity to concentrate and recover in a cyclic way LaIII.
DOI: 10.6084/m9.figshare.14304047.v1
title: Nickel-Cerium Layered Double Hydroxide as Electrocatalyst for Glycerol Oxidation

description: A new nickel based layered double hydroxide nanomaterial, Ni0.8Ce0.2-LDH, constituted by about 3 nm large nanoparticles exhibiting enhanced electrocatalytic properties towards oxidation of glycerol in alkaline media, was prepared by incorporation of 20 wt.% of CeIII ions into α-nickel hydroxide. This can be oxidized to CeIV, as demonstrated by X-ray photoelectron spectroscopy, a much electron withdrawing and oxidizing species responsible for electronic interactions and additional electrocatalytic active sites giving rise to synergic effects. High-resolution transmission electron microscopy images and the X-ray diffractograms indicated a material with a significantly lower size and degree of crystallinity than α-Ni(OH)2, one of the factors contributing to its enhanced electrochemical and electrocatalytic activity, as demonstrated by cyclic voltammetry and electrochemical impedance spectroscopy, suggesting a good potentiality for development of glycerol fuel cells.
DOI: 10.6084/m9.figshare.14304041.v1
title: Heterostructured Langmuir-Blodgett Films of Ruthenium Bipyridine with 1,3,4-Naphthooxadiazole-Derived Amphiphile Complex as a Charge Storage Electrode

description: The molecular control in Langmuir-Blodgett (LB) films may be exploited in charge storage electrodes provided a suitable choice of molecular architecture and components is made. In this paper, we employed a naphtyl-1,3,4-oxadiazole amphiphile (NFT1) and its complex [Ru(bpy)2NFT1]PF6 (RuNFT1) (bpy = 2,2’-bipyridine) in heterostructured LB films in a proof-of-principle production of charge storage. The optimized architecture contained a one-layer RuNFT1 deposited on a 9-layer NFT1 LB film, where the efficient packing of NFT1 inferred from spectroscopic measurements and Brewster angle microscopy (BAM) images was considered as relevant for ion diffusion. This packing was achieved owing to the π-stacking warranted by the planarity of the NFT1 naphtyl 1,3,4-oxadiazole ring, as confirmed with density functional theory (DFT) calculations. The top layer of the redox-active RuNFT1 provided an additional contribution with its Faradaic charge storage to the double layer capacitance of NFT1. Taken together, these results demonstrate that synergy may be achieved in combining distinct compounds in LB films toward efficient charge storage.
DOI: 10.6084/m9.figshare.14304039.v1
title: NO Photorelease from a Ruthenium Complex Assisted by Formation of a Supramolecular Dimer

description: This work presents the NO release from compound [Ru(biq)2(H2O)(NO)](PF6)3 (biq = 2,2’-biquinoline) with visible light irradiation (λirrad = 660 nm), assisted by the low-absorbing photosensitizer [Ru(biq)2Cl2]. The structure of both compounds were characterized by means of ESI-MS (electrospray ionization mass spectrometry). The NO+ stretching, ν(NO) = 1995 cm-1, is atypically shifted to higher energy. This observation, along with the E1/2 = 0.49 V (vs. Ag/AgCl) assigned to the Ru2+/3+ redox pair observed for compound [Ru(biq)2Cl2] and its photoreactivity in solution suggest that the RuII ion, when coordinated to two biquinolines, behaves as a hard Pearson acid. Molecular modelling results confirmed the typical geometry distortion of ruthenium-polypyridine complexes bearing sterically hindered ligands. They also suggest the formation of a supramolecular dimer, assembled by weak interaction between biquinoline ligands from each compound, that is claimed to be responsible for the high efficiency of the NO photorelease bimolecular sensitization.