25 research outputs found

    Determination of cadmium in used engine oil, gasoline and diesel by electrothermal atomic absorption spectrometry using magnetic ionic liquid-based dispersive liquid-liquid microextraction

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    In this study, a sensitive and matrix-effect free analytical method for Cd determination in engine oils and fuel samples by dispersive liquid-liquid microextraction with electrothermal atomic absorption spectrometry has been successfully developed. The extractant solvent used for the microextraction procedure was a magnetic ionic liquid (MIL) (i.e., bis(1-ethyl-3-methylimidazolium) tetrathiocyanatocobaltate (II) [Emim]2[Co(SCN)4]), which presents a paramagnetic property, and allows an easy phase separation using a magnet. In order to eliminate the well-known drawbacks of direct introduction of MIL in the graphite furnace, a back-extraction procedure was performed to transfer the analyte into an aqueous phase. The main experimental factors affecting the extraction of Cd (i.e., amount of sample and MIL, extraction and back-extraction time and concentration and amount of nitric acid) were optimized using a multivariate analysis consisting in two steps: a Plackett-Burman design followed by a circumscribed central composite design. Under optimum conditions (i.e., amount of sample: 6.2 g; amount of MIL: 119 mg; extraction time: 1 min; amount of nitric acid: 200 mg; nitric acid concentration: 1 mol L-1 and back-extraction time: 1 min), the proposed analytical method was validated and successfully used to analyze three real-world samples (i.e., used engine oil, gasoline and diesel). The three samples were spiked at two levels (i.e., 10 and 20 μg kg-1 of Cd for used engine oil and 1 and 3 μg kg-1 of Cd for gasoline and diesel). RSD and recovery values were within the range of 6–11% and 95–110%, respectively.The authors would like to thank the Spanish Government (projects n. CTQ2016-79991-R and PGC 2018-098363-100), Fundación Séneca (Project n. 19888/GERM/15) and European Union (FEDER funds) for the financial support

    Compensation of inorganic acid interferences in ICP-OES and ICP-MS using a Flow Blurring® multinebulizer

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    A new and easy method has been proposed for compensation of inorganic acid matrix effects in ICP-OES and ICP-MS. The method consists on an on-line standard addition calibration using a Flow Blurring® multinebulizer (FBMN-based system). Experimental conditions of the FBMN-based system are optimized for both ICP-OES and ICP-MS. Under optimized conditions recovery values obtained in the analysis of synthetic acid samples were close to 100% for HNO3 and HCl (with acid concentrations of up to 15% (w w-1)) and H2SO4 (up to 10% (w w-1)) for both plasma-based spectrochemical techniques. The applicability of the proposed method has been evaluated analyzing two whole milk powders, certified reference material and a commercial product, showing excellent recovery values. Compared with other calibration strategies and experimental setups used, the on-line standard addition calibration using the FBMN-based system is faster, easier to handle and significantly reduces reagents and sample consumption.The authors express their gratitude to the Spanish Ministry of Science and Innovation (projects n. CTQ2008 06730-C02-01 and PHB-2010-0018-PC), to the Coordenação de Aperfeiçoamento de Pessoal de Nível Superior in Brazil (Grant CAPES-DGU 243/11), and the Regional Government of Valencia (Spain) (projects n. ACOMP/2009/144 and ACOMP/2010/047) for financial support. The authors gratefully acknowledge OneNeb® (Division of Ingeniatrics Tecnologías S.L.) for the FBMN prototype provided. M.A.A. thanks the University of Alicante for his PhD fellowship. This work is part of the Ph.D. degree of M.A.A

    Aerosol generation of As and Se hydrides using a new Flow Blurring® multiple nebulizer for sample introduction in inductively coupled plasma optical emission spectrometry

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    A new Flow Blurring® multiple nebulizer (FBMN) has been used for the efficient generation of As and Se hydrides directly into the aerosol formed inside the spray chamber before detection by inductively coupled plasma optical emission spectrometry (ICP OES). The FBMN allowed the hydride generation directly into the spray chamber without using any additional device either for solution and gas control or for gas phase separation. Synthetic solutions containing As and Se plus Ca, Mg and K were used for evaluating matrix effects and Ge was suggested as internal standard. Limits of detection of 2.7 and 5.8 μg L− 1 were obtained for As and Se, respectively, when keeping the nebulization gas flow rate at 0.60 L min− 1 and the liquid flow rate at 0.67 mL min− 1. The developed procedure was applied for spiked digests of food samples and quantitative recoveries were attained. The combination of FBMN, internal standard and hydride generation is a robust and simple approach for generating As and Se hydrides directly into the aerosol.The authors express their gratitude to the Spanish Government (Grant CTQ2008-06730-C02-01, CTQ2011-23968 and PHB-2010-0018-PC) and to the Coordenação de Aperfeiçoamento de Pessoal de Nível Superior in Brazil (Grant CAPES-DGU 243/11) for financial support

    Analysis of waste electrical and electronic equipment (WEEE) using laser induced breakdown spectroscopy (LIBS) and multivariate analysis

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    This study shows the application of laser induced breakdown spectroscopy (LIBS) for waste electrical and electronic equipment (WEEE) investigation. Several emission spectra were obtained for 7 different mobiles from 4 different manufacturers. Using the emission spectra of the black components it was possible to see some differences among the manufacturers and some emission lines from organic elements and molecules (N, O, CN and C2) led to the highest contribution for this differentiation. Some polymeric internal parts in contact with the inner pieces of the mobiles and covered with a special paint presented a strong emission signal for Cr. The white pieces presented mainly Al, Ba and Ti in their composition. Finally, this study developed a procedure for LIBS emission spectra using chemometric strategies and suitable information can be obtained for identification of manufacturer and counterfeit products. In addition, the results obtained can improve the classification for establishing recycling strategies of e-waste.The authors are grateful to Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES- DGU, Grant 243/11), to the Spanish Government (Projects CTQ2008-06730-C02-01, CTQ2011-23968 and PHB2010-0018-PC), to Conselho Nacional de Desenvolvimento Científico e Tecnológico, CNPq (grants 304772/2012-7 and 474357/2012-0), and to Grant 2012/01769-3, São Paulo Research Foundation (FAPESP) for the financial support

    Aparatos y métodos para el diagnóstico de cáncer colorrectal

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    Número de Patente: ES 2881 149 B2La presente invención está relacionada con un aparato de extracción y análisis preciso, simple, sensible y eficaz de compuestos orgánicos volátiles (COVs) y de biomarcadores del cáncer colorrectal (CCR) en muestras sólidas y/o semisólidas, más concretamente en muestras de heces. Así mismo, la presente invención está relacionada con un método de diagnóstico y pronóstico de CCR ex vivo que comprende el análisis de COVs que son biomarcadores relacionados con el CCR en muestras de heces, mediante el uso de dicho aparato

    Disentangling microglia and astrocytes activation and neurodegeneration non-invasively using diffusion MRI

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    Póster presentado al 19th Meeting Spanish Society of Neuroscience (SENC), celebrado en Lleida del 3 al 5 de noviembre de 2021.This work was supported by European Research Council through a Marie Skłodowska-Curie Individual Fellowship (Grant #749506), Sybil-AA Europrean project and FEDER funds under the grant: PGC2018-101055-B-I00.Peer reviewe

    Enhancing Trace Metal Extraction from Wastewater: Magnetic Activated Carbon as a High-Performance Sorbent for Inductively Coupled Plasma Optical Emission Spectrometry Analysis

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    A new fast, sensitive, and environmentally friendly analytical method has been developed for the simultaneous determination of Ba, Be, Cd, Cr, Cu, Fe, Hg, Mn, Ni, Pb, and Zn in wastewater samples using inductively coupled plasma optical emission spectroscopy (ICP OES). A preconcentration step using a magnetic dispersive solid-phase extraction (MDSPE) technique with a new magnetic sorbent was performed. The new sorbent material was a carbon containing magnetic cobalt and nitrogen groups. This material was synthetized using controlled pyrolysis of a zeolitic imidazolate framework (i.e., ZIF-67). In order to optimize the experimental parameters that affect the MDSPE procedure, a multivariate optimization strategy, using Plackett–Burman and circumscribed central composite designs (CCD), was used. The method has been evaluated employing optimized experimental conditions (i.e., sample weight, 10 g; sample pH, 7.6; amount of sorbent, 10 mg; dispersive agent, vortex; complexing agent concentration, 0.5%; ionic concentration, 0%; eluent, HCl; eluent concentration, 0.5 M; eluent volume, 300 μL; elution time, 3 min and extraction time, 3 min) using external calibration. Limits of detection (LODs) in a range from 0.073 to 1.3 μg L−1 were obtained, and the repeatability was evaluated at two different levels, resulting in relative standard deviations below 8% for both levels (n = 5). An increase in the sensitivity was observed due to the high enrichment factors (i.e., 3.2 to 13) obtained compared with direct ICP OES analysis. The method was also validated through carrying out recovery studies that employed a real wastewater sample and through the analysis of a certified reference material (ERM®-CA713). The recovery values obtained with the real wastewater were between 94 and 108% and between 90 and 109% for the analysis of ERM®-CA713, showing negligible matrix effects

    The determination of V and Mo by dispersive liquid–liquid microextraction (DLLME) combined with laser-induced breakdown spectroscopy (LIBS)

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    Laser-induced breakdown spectroscopy (LIBS) is a promising analytical technique with well-known advantages and limitations. However, despite its growing popularity, this technique has been applied mainly to solid samples and there have been a smaller number of studies devoted to liquid samples. This lack of studies is mainly due to experimental difficulties in the analysis of liquid matrices. Sensitivity can be improved and matrix effects minimized in the LIBS analysis of aqueous samples by using a dispersive liquid–liquid microextraction (DLLME) procedure followed by drying the extract on a suitable surface prior to laser irradiation. The combination of DLLME-LIBS is fast, easy to use, and inexpensive. The small volume of the final extract is sufficient for LIBS analysis, and the procedure generates little waste. It is likely that this combination could be automated during future work. The limits of detection (LOD) and quantification (LOQ) achieved using the proposed method were 30 and 70 μg L−1 for Mo and 5 and 20 μg L−1 for V, respectively. Using this method, we analyzed samples of pharmaceutical, multimineral formulation, soil, mineral water and a reference material NCS ZC 85005 (Beef Liver). In the latter, the concentration of V was below the LOQ, and the recovery of Mo was 103%.The authors are grateful to Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES-DGU and grants 243/11 and 1267/01-2), the Spanish Government (Projects CTQ2011-23968 and PHB2010-0018-PC), the Regional Government of Valencia (Spain) (ACOMP/2013/072), Conselho Nacional de Desenvolvimento Científico e Tecnológico, CNPq (grants 304772/2012-7 and 474357/2012-0) and Grants 2012/01769-3 and 2012/50827-6, São Paulo Research Foundation (FAPESP), for the financial support

    Experimental and computational biophysics to identify vasodilator drugs targeted at TRPV2 using agonists based on the probenecid scaffold

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    CatedresAltres ajuts: Ministerio de Universidades Margarita Salas Award (MGSD2021-10 to M.L.-M.); Universitat Autònoma De Barcelona Predoctoral Fellowship (B21P0033 to E.C.-H.); the Royal Society of Chemistry for Financial Support through a RS International Exchanges award (IES\R\193089 to C.D.); Deutsche Forschungsgemeinschaft (DFG, German Research Foundation) through the collaborative research center 1507 “Membrane-associated Protein Assemblies, Machineries, and Supercomplexes” – Project ID 450648163 (to UAH); Cluster of Excellence “Balance of the Microverse” EXC2051 – Project-ID 390713860 (to UAH).TRP channels are important pharmacological targets in physiopathology. TRPV2 plays distinct roles in cardiac and neuromuscular function, immunity, and metabolism, and is associated with pathologies like muscular dystrophy and cancer. However, TRPV2 pharmacology is unspecific and scarce at best. Using in silico similarity-based chemoinformatics we obtained a set of 270 potential hits for TRPV2 categorized into families based on chemical nature and similarity. Docking the compounds on available rat TRPV2 structures allowed the clustering of drug families in specific ligand binding sites. Starting from a probenecid docking pose in the piperlongumine binding site and using a Gaussian accelerated molecular dynamics approach we have assigned a putative probenecid binding site. In parallel, we measured the EC50 of 7 probenecid derivatives on TRPV2 expressed in Pichia pastoris using a novel medium-throughput Ca influx assay in yeast membranes together with an unbiased and unsupervised data analysis method. We found that 4-(piperidine-1-sulfonyl)-benzoic acid had a better EC50 than probenecid, which is one of the most specific TRPV2 agonists to date. Exploring the TRPV2-dependent anti-hypertensive potential in vivo, we found that 4-(piperidine-1-sulfonyl)-benzoic acid shows a sex-biased vasodilator effect producing larger vascular relaxations in female mice. Overall, this study expands the pharmacological toolbox for TRPV2, a widely expressed membrane protein and orphan drug target
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