61. Development of a simple method for the extraction of pharmaceuticals from fishTopić Jelena, Klančar Anita, Trontelj Jurij, Roškar Robert, 2016, published scientific conference contribution abstract Abstract: Pharmaceuticals are considered as emerging pollutants of particular concern due to their continuous release into the environment and the potential impact on aquatic organisms. The selection of the target compounds for evaluation in fish tissue was based on physico-chemical properties, bioaccumulation potential and the results of the screening of pharmaceuticals in the effluent of WWTP Sevnica in March 2015. We chose tramadol, risperidone, desipramine, carbamazepine, irbesartan, naproxen, valsartan, atorvastatin, triclosan, simvastatin and diclofenac. The method was developed on muscle tissue and is based on the tissue homogenization with stainless steel beads, followed by extraction with acetonitrile, centrifugation and sample clean-up with solid-phase extraction (SPE). The instrumental analysis was performed with LC-MS/MS. The best and the most reproducible recoveries were observed for the samples that were diluted to 25 mL with 50 mM phosphate buffer pH 7. The method was validated and the linearity range was established, which was in the range of 0.1 – 1000 ng/g, depending of the compound. The recoveries for the target pharmaceuticals were in the range of 24.0 – 108.5 %, with good reproducibility as the relative RSD values for all compounds were below 7.5 %. LOQ values for the compounds were in the 0.1 – 50 ng/g range. We applied the method to the fish tissue samples from the river Sava and from the aquaculture establishment. We chose muscle, liver, skin and kidney tissue samples. The results showed presence of tramadol and carbamazepine in some tissue, but the concentrations were below the LOQ.
Keywords: pharmaceuticals, fish, SPE, LC-MS/MS
Published in RUNG: 16.11.2016; Views: 5669; Downloads: 0
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62. The filter loading effect by ambient aerosols in filter absorption photometers depends on the mixing state of the sampled particlesLuka Drinovec, Asta Gregorič, Peter Zotter, Robert Wolf, Emily Anne Bruns, Andre S.H. Prevot, Jean-Eudes Petit, Olivier Favez, JEAN SCIARE, Ian J. Arnold, Rajan K. Chakrabarty, Hans Moosmüller, Agnes Fülöp-Miller, Griša Močnik, 2016, original scientific article Keywords: black carbon, mixing state, Aethalometer, filter-loading effect
Published in RUNG: 02.11.2016; Views: 5557; Downloads: 281
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63. Study of Li-S batteries by S K-edge RIXS spectroscopyMatjaž Kavčič, Matjaž Žitnik, Klemen Bučar, Marko Petrič, Iztok Arčon, Robert Dominko, Alen Vižintin, 2016, published scientific conference contribution abstract Abstract: Li-S batteries are considered as one of the most promising candidates for future batteries in applications where high energy density is required [1]. Despite that the general principle of operation is known for a long time [2], the lack of detailed understanding of relevant operation mechanisms has so far prevented their extensive use. A Li-S battery is composed of a lithium metal anode and a sulfur based cathode, separated by a porous separator wetted with electrolyte. During the battery cycle the reduction and oxidation of S to Li2S and back proceeds through a complicated equilibrium mixture of compounds that are typically dissolved in the electrolyte in the form of long and short chain polysulfides. In order to improve our understanding of polysulfide formation and its interactions within electrode, which are essential to achieve the long term cycling stability, development and application of new analytical tools is required.
In this work sulfur K-edge resonant X-ray emission (RXES) measurements were performed on the Li-S battery in operando mode. The experiment was performed at the ID26 beamline at ESRF using the Johansson type tender x-ray emission spectrometer [3]. Full K-L RIXS maps were recorded on a set of chemically prepared Li2Sx sample standards characterized by different Li:S stoichiometric ratio, followed by the operando measurements on Li-S battery. Using the spectra recorded on Li2Sx standards two excitation energies were chosen and RXES spectra from the back of the battery cathode were sequentially acquired during one discharge cycle (C20). The relative amounts of each sulfur compound in the cathode during the discharge cycle were determined from the linear combination fit using measured reference standard spectra. Because of resonant excitation conditions the sensitivity for the polysulfide detection was significantly enhanced. Our work sets up S K-edge RIXS spectroscopy as an important analytical tool to study the mechanism of Li-polysulfide formation in the cathode and their interaction with the host matrix and electrolyte.
Keywords: RIXS, RXES, Li-S battery, operando, Sulphur K-edge XANES, Lithium polysulphides, Li2S
Published in RUNG: 28.06.2016; Views: 5682; Downloads: 0
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70. Electrical conductivity in 3,4,9,10-perylenetetracarboxylic dianhidride (PTCDA)Gvido Bratina, Robert Hudej, Marko Zavrtanik, John Nimly Brownell, 2001, original scientific article Abstract: The transient photoresponse in 3,4,9,10-perylenetetracarboxylic dianhydride was examined in metal/organic semiconductor/metal heterostructures. Electron-hole pairs are generated within the structure for fields higher than 5 X 10[sup]4 V/cm as a consequence of the exciton dissociation. The mobility of the electrons perpendicular to the molecular layers increases with the applied electric field and saturates for fields higher than 5 X 10[sup]4 V/cm.
Keywords: organic semiconductor, thin films, transient photoconductivity
Published in RUNG: 10.07.2015; Views: 6602; Downloads: 40
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