Suchergebnisse

et al. ; The efficient conversion between thermal and electrical energy by means of durable, silent and scalable solid-state thermoelectric devices has been a long standing goal. While nanocrystalline materials have already led to substantially higher thermoelectric efficiencies, further improvements are expected to arise from precise chemical engineering of nanoscale building blocks and interfaces. Here we present a simple and versatile bottom-up strategy based on the assembly of colloidal nanocrystals to produce consolidated yet nanostructured thermoelectric materials. In the case study on the PbS-Ag system, Ag nanodomains not only contribute to block phonon propagation, but also provide electrons to the PbS host semiconductor and reduce the PbS intergrain energy barriers for charge transport. Thus, PbS-Ag nanocomposites exhibit reduced thermal conductivities and higher charge carrier concentrations and mobilities than PbS nanomaterial. Such improvements of the material transport properties provide thermoelectric figures of merit up to 1.7 at 850 K. ; At IREC, work was supported by European Regional Development Funds and the Framework 7 program under project UNION (FP7-NMP 310250). M.I. and S.O. thank AGAUR for their Beatriu i Pinos post-doctoral grant (2013 BP-A00344) and the PhD grant, respectively. A.G. thanks to the Turkish Ministry of National Education for the PhD grant. A.G. and J.A. acknowledge the Spanish MINECO MAT2014-51480-ERC (e-ATOM) and the ICN2 Severo Ochoa Excellence Program. Z.L. and Y.L. thanks the China Scholarship Council for their PhD grant. IREC and ICN2 groups acknowledge the funding from Generalitat de Catalunya 2014SGR1638. The work performed at Rutgers was supported by NSF grant number 1400246. M.V.K. acknowledges partial financial support by the European Union (EU) via FP7 ERC Starting Grant 2012 (Project NANOSOLID, GA No. 306733). ; Peer Reviewed

The herbicide bromacil has been extensively used in the Spanish Mediterranean region, and although plant protection products containing bromacil have been withdrawn by the European Union, this compound is still frequently detected in surface and ground water of this area. However, the fast and complete disappearance of this compound has been observed in water intended for human consumption, after it has been subjected to chlorination. There is a concern about the possible degradation products formed, since they might be present in drinking water and might be hazardous. In this work, the sensitive full-spectrum acquisition, high resolution and exact mass capabilities of hybrid quadrupole time-of-flight (QTOF) mass spectrometry have allowed the discovery and proposal of structures of transformation products (TPs) of bromacil in water subjected to chlorination. Different ground water samples spiked at 0.5 µg/mL were subjected to the conventional chlorination procedure applied to drinking waters, sampling 2-mL aliquots at different time intervals (1, 10 and 30 min). The corresponding non-spiked water was used as control sample in each experiment. Afterwards, 50 μL of the water was directly injected into an ultra-high-pressure liquid chromatography (UHPLC)/electrospray ionization (ESI)-(Q)TOF system. The QTOF instrument enabled the simultaneous recording of two acquisition functions at different collision energies (MSE approach): the low-energy (LE) function, fixed at 4 eV, and the high-energy (HE) function, with a collision energy ramp from 15 to 40 eV. This approach enables the simultaneous acquisition of both parent (deprotonated and protonated molecules) and fragment ions in a single injection. The low mass errors observed for the deprotonated and protonated molecules (detected in LE function) allowed the assignment of a highly probable molecular formula. Fragment ions and neutral losses were investigated in both LE and HE spectra to elucidate the structures of the TPs found. For those compounds that displayed ...

The presence of a wide variety of organic pollutants with different physico-chemical characteristics has been investigated in wastewater samples from a municipal solid waste treatment plant placed at Castellón, Spain. An advanced analytical strategy has been applied, consisting on the combined used of two powerful and complementary techniques, GC and LC, both hyphenated with tandem mass spectrometry with triple quadrupole analyzers. The GC-MS/MS method was based on sample extraction using C18 SPE cartridges and allowed the determination of around 60 compounds from different chemical families, such as PAHs, octyl/nonyl phenols, PCBs, organochlorine compounds, insecticides, herbicides and PBDEs. Most of compounds selected are included as priority contaminants in the European Union (EU) Water Directive. The UHPLC-MS/MS method, which provided high chromatographic resolution and sensitivity and short analysis time, used a sample extraction with OASIS HLB SPE cartridges and allowed the determination of 37 (more polar) pesticides. The methodology developed has been applied to the analysis of 41 water samples (20 non-treated, raw leachates, and 21 treated) collected between March 2007 and February 2009. Treated (reverse osmosis) water samples analyzed rarely exceeded 0.5 μg/L for the contaminants investigated. As expected, in non-treated leachates the number of detections and the concentration levels found were notably higher than in treated waters. The most commonly detected pollutants were herbicides (simazine, terbuthylazine, terbutryn, terbumeton, terbacil and diuron), together with fungicides (thiabendazole and carbendazim) and 4-t-octylphenol. In the light of data obtained, it has been proven that reverse osmosis process used for water treatment was efficient and notably reduced the levels of organic contaminants found in raw leachate samples. 2 In order to investigate the presence of other non-target contaminants, water samples were also analyzed by using GC-TOF MS and LC-QTOF MS. Several organic pollutants that ...

A suspicious white powder labeled "idanyl-biphenyl-amninone," which was seized by customs officials at the "channel island" of Jersey, UK, was brought to our laboratory for identification and characterization of its structure. The elucidation process required the use of several complementary analytical techniques, including gas chromatography–mass spectrometry, liquid chromatography coupled with high-resolution mass spectrometry, nuclear magnetic resonance spectroscopy, and X-ray crystallography. The unknown compound was ultimately identified as 1-(2,3-dihydro-1H-inden-5-yl)-2-phenyl-2-(pyrrolidin-1-yl)-ethanone, a novel cathinone derivative. To the best of our knowledge, this compound has not been registered in the CAS or IUPAC databases. However, it has recently been marketed on the Internet as "indapyrophenidone," and we therefore propose this as the common name of the compound. The results of this study may serve forensic and clinical laboratories in the identification of its related compounds with similar backbone structure using the information reported in this article obtained by the application of advanced analytical techniques. It may also lead to timely and effective response on the part of legislators and law enforcement.

To examine the impact of the second legal ban on synthetic cannabinoids (SCs) in the UK in February 2013, we surveyed the UK legal high market just before and after the change in legislation, looking for new SCs. The technique gas chromatography–mass spectrometry (GC–MS) in electron ionization mode, most widely applied for analysis, was found to be insufficient for the identification of several SCs, and therefore liquid chromatography–high-resolution mass spectrometry (LC–HR-MS) was required. LC–HR-MS(/MS) measurements of the protonated molecules and product ions allowed the detection of up to 27 compounds as the third-generation SCs in the samples analysed as part of this study, including two unknown compounds that were tentatively identified as F2201 and dealkyl-SDB-006. Our results showed that banned compounds were removed from the market on the day when the ban was in place, and were replaced by other SCs immediately after the ban. In only one occasion, a banned compound (UR-144) was detected after the date when the new legislation came into place. It is also noteworthy that regardless of the change in legislation, new compounds continued to enter the market. Product ion spectral information on the third-generation SCs at different collision energies given in this paper will be of help for forensic and clinical laboratories and will facilitate the detection and identification of new SCs by laboratories of control. This information is very valuable for law enforcement and policymakers and will be of help in future prevention programs.

In the quest for more efficient thermoelectric material able to convert thermal to electrical energy and vice versa, composites that combine a semiconductor host having a large Seebeck coefficient with metal nanodomains that provide phonon scattering and free charge carriers are particularly appealing. Here, we present our experimental results on the thermal and electrical transport properties of PbS-metal composites produced by a versatile particle blending procedure, and where the metal work function allows injecting electrons to the intrinsic PbS host. We compare the thermoelectric performance of composites with microcrystalline or nanocrystalline structures. The electrical conductivity of the microcrystalline host can be increased several orders of magnitude with the metal inclusion, while relatively high Seebeck coefficient can be simultaneously conserved. On the other hand, in nanostructured materials, the host crystallites are not able to sustain a band bending at its interface with the metal, becoming flooded with electrons. This translates into even higher electrical conductivities than the microcrystalline material, but at the expense of lower Seebeck coefficient values. ; This work was supported by the European Regional Development Funds, the Framework 7 program under project UNION (No. FP7-NMP-2012-310250), and the Spanish MINECO Project BOOSTER (No. ENE2013-46624-C4-3-R). Y.L. thanks the China Scholarship Council (No. CSC 201406500003) for the scholarship support. M.I., O.D., and S.O. thank AGAUR for their Beatriu de Pinós postdoctoral Grant No. (2013 BP-A00344) and Ph.D. grants. M.V.K. acknowledges the partial financial support from the European Union (EU) via FP7 ERC Starting Grant 2012 (Project NANOSOLID, GA No. 306733). Authors also acknowledge the funding from Generalitat de Catalunya 2014 SGR 1638. ; Peer Reviewed

The bottom-up assembly of colloidal nanocrystals is a versatile methodology to produce composite nanomaterials with precisely tuned electronic properties. Beyond the synthetic control over crystal domain size, shape, crystal phase, and composition, solution-processed nanocrystals allow exquisite surface engineering. This provides additional means to modulate the nanomaterial characteristics and particularly its electronic transport properties. For instance, inorganic surface ligands can be used to tune the type and concentration of majority carriers or to modify the electronic band structure. Herein, we report the thermoelectric properties of SnTe nanocomposites obtained from the consolidation of surface-engineered SnTe nanocrystals into macroscopic pellets. A CdSe-based ligand is selected to (i) converge the light and heavy bands through partial Cd alloying and (ii) generate CdSe nanoinclusions as a secondary phase within the SnTe matrix, thereby reducing the thermal conductivity. These SnTe-CdSe nanocomposites possess thermoelectric figures of merit of up to 1.3 at 850 K, which is, to the best of our knowledge, the highest thermoelectric figure of merit reported for solution-processed SnTe. ; This work was financially supported by the European Union (EU) via FP7 ERC Starting Grant 2012 (Project NANOSOLID, GA No. 306733). M.I. was supported by IST Austria, and by ETH Zurich via ETH career seed grant (SEED-18 16-2). Y.L. acknowledges funding from the European Union's Horizon 2020 research and innovation programme under the Marie Sklodowska-Curie grant agreement No. 754411. IREC acknowledges funding from Generalitat de Catalunya (2014SGR1638). J.A. acknowledge funding from Generalitat de Catalunya 2017 SGR 327 and the Spanish MINECO coordinated projects between IREC and ICN2 ENE2017-85087-C3. ICN2 acknowledges support from the Severo Ochoa Program (MINECO, Grant SEV-2017-0706) and is funded by the CERCA Programme/Generalitat de Catalunya. ; Peer reviewed

This work presents a strategy for elucidation of unknown migrants from plastic food contact materials (baby bottles) using a combination of analytical techniques in an untargeted approach. First, gas chromatography (GC) coupled to mass spectrometry (MS) in electron ionisation mode was used to identify migrants through spectral library matching. When no acceptable match was obtained, a second analysis by GC-(electron ionisation) high resolution mass spectrometry time of flight (TOF) was applied to obtain accurate mass fragmentation spectra and isotopic patterns. Databases were then searched to find a possible elemental composition for the unknown compounds. Finally, a GC hybrid quadrupole-TOF-MS with an atmospheric pressure chemical ionisation source was used to obtain the molecular ion or the protonated molecule. Accurate mass data also provided additional information on the fragmentation behaviour as two acquisition functions with different collision energies were available (MSE approach). In the low-energy function, limited fragmentation took place, whereas for the high-energy function, fragmentation was enhanced. For less volatile unknowns, ultra-high pressure liquid chromatography-quadrupole-TOF-MS was additionally applied. Using a home-made database containing common migrating compounds and plastic additives, tentative identification was made for several positive findings based on accurate mass of the (de)protonated molecule, product ion fragments and characteristic isotopic ions. Six illustrative examples are shown to demonstrate the modus operandi and the difficulties encountered during identification. The combination of these techniques was proven to be a powerful tool for the elucidation of unknown migrating compounds from plastic baby bottles. ; Federal Government Service for Public Health of Belgium through project: ALTPOLYCARB Generalitat Valenciana (Group of Excellence Prometeo) II/2014/023 ; ISIC/2012/016 Envi-Food

The Water Framework Directive 2000/60/EC implemented by the European Union established as the main objectives to achieve a "good ecological and chemical status" of the surface water and a "good quantitative and chemical status" of groundwater bodies. One of the major pressures affecting water bodies comes from the use of pesticides and their potential presence in the water ecosystems. For this purpose, the reliable determination of pesticides and their transformation products (TPs) in natural waters (both surface and groundwater) is required. The high number of compounds potentially reaching the aquatic environment makes extraordinary difficult, if not impossible, to investigate all these compounds even using the most powerful analytical techniques. Among these, liquid chromatography coupled to high-resolution mass spectrometry is emphasized due to its strong potential for detection and identification of many organic contaminants thanks to the accurate-mass full spectrum acquisition data. This work focuses on wide-scope screening of many pesticides and their TPs in surface water and groundwater samples, collected between March and May 2017, in the Júcar River Hydrographical Basin, Spain. For this purpose, a home-made database containing more than 500 pesticides and TPs was employed. Analyses performed by liquid chromatography coupled to quadrupole-time of flight mass spectrometry (LC-QTOF MS) allowed the identification of up to 27 pesticides and 6 TPs. The most detected compounds in groundwater were the herbicides atrazine, simazine, terbuthylazine, and their TPs (atrazine-desethyl, terbumeton-desethyl and terbuthylazine-desethyl). Regarding surface water, the fungicides carbendazim, thiabendazole and imazalil, the herbicide terbutryn and the TP terbumeton-desethyl were also detected. These results illustrate the wide use of these compounds (in the present or in the recent past) in the area under study and the vulnerability of the water bodies, and are in accordance with previous findings in other water bodies ...

SnSe has emerged as one of the most promising materials for thermoelectric energy conversion due to its extraordinary performance in its single-crystal form and its low-cost constituent elements. However, to achieve an economic impact, the polycrystalline counterpart needs to replicate the performance of the single crystal. Herein, we optimize the thermoelectric performance of polycrystalline SnSe produced by consolidating solution-processed and surface-engineered SnSe particles. In particular, the SnSe particles are coated with CdSe molecular complexes that crystallize during the sintering process, forming CdSe nanoparticles. The presence of CdSe nanoparticles inhibits SnSe grain growth during the consolidation step due to Zener pinning, yielding a material with a high density of grain boundaries. Moreover, the resulting SnSe-CdSe nanocomposites present a large number of defects at different length scales, which significantly reduce the thermal conductivity. The produced SnSe-CdSe nanocomposites exhibit thermoelectric figures of merit up to 2.2 at 786 K, which is among the highest reported for solution-processed SnSe. ; This work was financially supported by IST Austria and the Werner Siemens Foundation. Y.L. acknowledges funding from the European Union's Horizon 2020 research and innovation program under the Marie Sklodowska-Curie grant agreement No. 754411. S.L. and M.C. received funding from the European Union's Horizon 2020 research and innovation program under the Marie Skłodowska-Curie Grant Agreement No. 665385. J.D. acknowledges funding from the European Union's Horizon 2020 research and innovation program under the Marie Sklodowska-Curie grant agreement no. 665919 (P-SPHERE) cofunded by Severo Ochoa Programme. C.C. acknowledges funding from the FWF "Lise Meitner Fellowship" grant agreement M 2889-N. Y.Y. and O.C.-M. acknowledge the financial support from DFG within the project SFB 917: Nanoswitches. M.C.S. received funding from the European Union's Horizon 2020 research and innovation programme under ...

Bottom-up approaches for producing bulk nanomaterials have traditionally lacked control over the crystallographic alignment of nanograins. This limitation has prevented nanocrystal-based nanomaterials from achieving optimized performances in numerous applications. Here we demonstrate the production of nanostructured BixSb2–xTe3 alloys with controlled stoichiometry and crystallographic texture through proper selection of the starting building blocks and the adjustment of the nanocrystal-to-nanomaterial consolidation process. In particular, we hot pressed disk-shaped BixSb2–xTe3 nanocrystals and tellurium nanowires using multiple pressure and release steps at a temperature above the tellurium melting point. We explain the formation of the textured nanomaterials though a solution–reprecipitation mechanism under a uniaxial pressure. Additionally, we further demonstrate these alloys to reach unprecedented thermoelectric figures of merit, up to ZT = 1.96 at 420 K, with an average value of ZTave = 1.77 for the record material in the temperature range 320–500 K, thus potentially allowing up to 60% higher energy conversion efficiencies than commercial materials. ; This work was supported by the European Regional Development Funds. Y.L. and Y.Z. thank the China Scholarship Council for scholarship support. M.V.K. acknowledges partial financial support by the European Union (EU) via FP7 ERC Starting Grant 2012 (Project NANOSOLID, GA No. 306733). S.M.-S. acknowledges funding from "Programa Internacional de Becas 'la Caixa'-Severo Ochoa". IREC and ICN2 acknowledge funding from Generalitat de Catalunya 2014 SGR 1638. ICN2 acknowledges support from the Severo Ochoa Programme (MINECO, Grant No. SEV-2013-0295) and is funded by the CERCA Programme/Generalitat de Catalunya. ; Peer reviewed

Background: Meniere disease (MD) is an inner ear disorder associated with comorbidities such as autoimmune diseases or migraine. This study describes clinical and cytokine profiles in MD according to the age of onset of the condition. Methods: A cross-sectional study including 83 MD patients: 44 with early-onset MD (EOMD, 50 years old), 64 patients with migraine and 55 controls was carried out. Clinical variables and cytokines levels of CCL3, CCL4, CCL18, CCL22, CXCL,1 and IL-1β were compared among the different groups. Results: CCL18 levels were higher in patients with migraine or MD than in controls. Elevated levels of IL-1β were observed in 11.4% EOMD and in 10.3% LOMD patients and these levels were not dependent on the age of individuals. EOMD had a longer duration of the disease (p = 0.004) and a higher prevalence of migraine than LOMD (p = 0.045). Conclusions: Patients with EOMD have a higher prevalence of migraine than LOMD, but migraine is not associated with any cytokine profile in patients with MD. The levels of CCL18, CCL3, and CXCL4 were different between patients with MD or migraine and controls. ; ISCIII and European Regional Funds (Grants PI17/01644 and PI20/01126) ; Andalusian Health Government (Grant PE-0356-2018). ; Andalusian Health Government (Grant PI-0027-2020).

In this article, a dataset from a collaborative nontarget screening trial organised by the NORMAN Association is used to review the state-of-the-art and discuss future perspectives of non-target screening using high-resolution mass spectrometry in water analysis. A total of 18 institutes from 12 European countries analysed an extract of the same water sample collected from the River Danube with either one or both of liquid and gas chromatography coupled with mass spectrometry detection. This article focuses mainly on the use of high resolution screening techniques with target, suspect, and non-target workflows to identify substances in environmental samples. Specific examples are given to emphasise major challenges including isobaric and co-eluting substances, dependence on target and suspect lists, formula assignment, the use of retention information, and the confidence of identification. Approaches and methods applicable to unit resolution data are also discussed. Although most substances were identified using high resolution data with target and suspect-screening approaches, some participants proposed tentative non-target identifications. This comprehensive dataset revealed that nontarget analytical techniques are already substantially harmonised between the participants, but the data processing remains time-consuming. Although the objective of a Bfullyautomated identification workflow^ remains elusive in the short term, important steps in this direction have been taken, exemplified by the growing popularity of suspect screening approaches. Major recommendations to improve non-target screening include better integration and connection of desired features into software packages, the exchange of target and suspect lists, and the contribution of more spectra from standard substances into (openly accessible) databases. ; This work was supported in part by the SOLUTIONS project, which received funding from the European Union's Seventh Framework Programme for research, technological development and demonstration under Grant Agreement No. 603437.