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Determination of 136 pharmaceuticals and hormones in sewage sludge using quick, easy, cheap, effective, rugged and safe extraction followed by analysis with liquid chromatography-time-of-flight-mass spectrometry.
The aim of this study was to develop an analytical method for the analysis of a wide range of hormonal steroids and pharmaceutical compounds in sewage sludge. Thus, 136 substances were selected, including 119 pharmaceuticals and 17 hormonal steroids. An innovative sample preparation procedure based on the quick, easy, cheap, effective, rugged and safe (QuEChERS) method was developed. The analysis was then performed using liquid chromatography coupled with time-of-flight mass spectrometry. This analytical pr...
A theory is proposed to relate the elution times of the adsorption front shocks of breakthrough curves recorded during classical dynamic frontal analysis (FA) experiments with selected compounds and their adsorption isotherms in solid/supercritical fluid adsorption systems. The actual density and viscosity of binary mixtures of CO2 and methanol were obtained from the NIST REPPROP software. Diluted solutions of S-naproxen were considered (
Give me four: The synthesis, structure, and reactivity of [GeCl](+) and [SnCl](+) cations bearing a carbodiphosphorane as ancillary ligand are presented. In the Ge compound, simultaneous σ and π donation from the carbodiphosphorane to Ge is observed (see HOMO (left) and HOMO-1 (right); C black, H white, P orange, Cl green, Ge purple (not visible)), whereas only the σ dative component is present in the Sn analogue.
Photoelectric charging of particles is a powerful tool for online characterization of submicrometer aerosol particles. Indeed photoionization based techniques have high sensitivity and chemical selectivity. Moreover, they yield information on electronic properties of the material and are sensitive to the state of the surface. In the present study the photoionization charging efficiency, i.e., the ratio between the generated positive ions and the corresponding neutral ones, for different classes of flame-gen...
Five oxygenated carbon-centered free radical reactions with nitrogen dioxide (NO2) have been studied in direct time-resolved measurements. Experiments were conducted in a temperature-controlled flow tube reactor coupled to a 193 nm exciplex laser photolysis and a resonance gas lamp photoionization mass spectrometer. Reactions were investigated under pseudofirst-order conditions, with the NO2 concentrations of the experiments in great excess over the initial radical concentrations ([R]0 ≪ [NO2]). The study...
The crystallization behavior and the orientation of linear alkane hentetracontane (C41) confined in cylindrical nanoporous alumina templates with different surface energies were investigated by nonisothermal crystallization and X-ray diffraction. The surface of pristine nanoporous alumina was modified to have low surface energy by grafting with polydimethylsiloxane. In the pristine nanoporous alumina, C41 crystallized at two crystallization temperature ranges, lower than bulk, and exhibited the decreased Av...
The two lowest singlet potential energy surfaces of the hydrazoic acid are explored using high-level quantum chemistry calculations, revealing isomeric forms, transition states, and a new path for the nitrogen ring-closing mechanism in the ground state. The reaction of cyc-N3 with hydrogen is shown to proceed through a barrierless path that dissociates to N2 + NH((1)Δ) without reaching the HN3 global minimum. Several intersections between the two states are localized for both N3 isomers near the N3 + H dis...
A chromatographic process based on monoliths for purification of infective baculovirus without prior concentration step has been established. Baculovirus produced in Spodoptera frugiperda cells (Sf-9) were harvested by centrifugation, filtered through 0.8μm filters and directly loaded onto radial 1mL anion exchange monoliths with a channel size of 1.5-2.0μm operated at a volumetric flow rate of one bed volume per minute. Optional an epoxy monolith was used as pre-column to reduce interfering compounds and...
A three-component homogeneous catalyst system has been prepared with an Ir(III) complex as the photosensitizer, artificial hydrogenases bearing a diiron core and dendritic frameworks as the proton reduction catalyst, and triethylamine as the sacrificial electron donor. An initial turnover frequency of over 7240 h(-1) and a quantum yield of up to 28 % were determined for the photocatalytic evolution of hydrogen.
An organocatalytic asymmetric direct aldol addition reaction that involves cleavage of a carbon-carbon bond through the release of trifluoroacetate was developed. The protocol is wide in scope, generating the desired oxindoles of biological interest in nearly quantitative yields (up to 99 %) with excellent enantioselectivities (up to 98 % ee) and diastereoselectivities (up to 99:1 d.r.).
Sleeping beauty: The 5-(2'-Deoxyuridinyl)methyl radical 1 is a key intermediate in the thymine oxidative reaction mediated by reactive oxygen species. Evidence is presented that 1 is prone to both oxidation and reduction reactions at the absence of O2 . These results question the current paradigm and suggest that the redox chemistry of 1, which has been largely overlooked in the past, may play a major role in determining the fate of 1.
Fluorescent organotin sensing: Molecular recognition driven by halogen-bonding interactions and the phenomenon of aggregation-induced emission were combined to construct fluorescent chemosensors. Binuclear ruthenium complexes containing multiple isocyanide ligands were synthesized as nonluminescent receptors that emit red fluorescence upon interacting with organotin halides (see picture; QY=quantum yield).
Born to dye: Five fluorescein analogues were synthesised. One analogue was found to emit in the NIR region with a high quantum yield, excellent photostability and good permeability. Three derivatives were found to specifically stain mitochondria and one dye responds to thiols with a strong turn-on NIR fluorescence signal and colorimetric change, in vitro and in vivo.
11-Ring heterocyclic diimides were synthesized and found to be planar and to exhibit a slipped face-to-face π stacking. Variation of the substituents tunes the electronic structure and properties. In n-channel organic field-effect transistors, the new organic semiconductors have a high electron mobility. When they were used as acceptor material in polymer solar cells, a power conversion efficiency of 1.8 % was obtained.
Hybrid materials: The multistep growth of various coordination polymers has been demonstrated to induce formation of well-defined multilayered core-shell structures. Composition of these structures can be fine-tuned by altering the sequence of the multistep-growth process.
Suppressing the urge to translate: Sequences with the potential to form G-quadruplexes were identified in the open reading frames of E. coli genes. These sequences were found to form parallel G-quadruplexes and to suppress translation of the mRNAs into proteins both in vitro and in cells.
Turn the volume down: Coupling a high-pressure electroosmotic pump (EOP) and a microfabricated chip-injector with a bare narrow capillary-hydrodynamic chromatographic system (BaNC-HDC), enables samples to be injected at low-picoliter volumes, analytes to be eluted at picoliters per minute, and a wide size range of DNA fragments to be resolved rapidly in free solution at the single-molecule level.
The first enantiospecific total synthesis of the antibacterial natural product (+)-pleuromutilin has been achieved. The approach includes the synthesis of a non-racemic cyclisation substrate from (+)-trans-dihydrocarvone, a highly selective SmI2 -mediated cyclisation cascade, an electron transfer reduction of a hindered ester, and the first efficient conversion of (+)-mutilin to the target.
Crafty aminals: The in situ generation of hitherto unattainable alkynyl-substituted N-Boc-protected imines was realized by the acid-catalyzed elimination of tert-butyl carbamate from N-Boc aminals. A wide variety of N-Boc imines can be generated, which can then be utilized for subsequent carbon-carbon bond-forming reactions, such as Mannich-type reactions.
ORR inspiring: Multilayers of Co(2+) and porphyrin, fabricated on the surface of reduced graphene oxide sheets by a layer-by-layer assembly technique, are potentially cost-effective and high-efficient oxygen reduction reaction (ORR) catalysts. The multilayers have comparable electrocatalytic activity to commercial C/Pt catalysts, but much better methanol tolerance and long-term stability toward ORR.
Cores and effect: Unlike homobimetallic analogues, the heterobimetallic CuNi bis(μ-oxo) diamond core has nucleophilic oxo groups. A similar heterobimetallic core may, therefore, act as a viable intermediate during the deformylation of fatty aldehydes by cyanobacterial aldehyde decarbonylase.
Learning to let go: Controlled release of cargo (purple cubes) from lectin (blue squares)-gated nanopores was achieved using mannose (green loops)-functionalized mesoporous silica. The protein nanogates could be opened either by decreasing the pH of the buffer or by adding competing glucose (yellow rings) to release the cargo from the pores.
Flexible even if constrained: A polyamine host recognizes dicarboxylic acids in solution and in the solid state, with the highest selectivity towards maleic acid, binding it from mixtures with up to five other dicarboxylic acids, including fumaric acid. Recognition using mechanochemistry is a dynamic process involving intermediate phases, resulting in the same selectivity as achieved by crystallization from solution.
Bermuda triangle: The first molecule containing a cyclic three-membered SnCP ring has been synthesized and characterized. This Sn(II) P Lewis pair reacts at room temperature with alkynes and pentene to give the five-membered cyclic addition products. In the case of pentene, this reaction is reversible at room temperature. Trip=2,4,6-iPr3 C6 H2 .
A randomized crossover study explored whether viewing different scenes prior to a stressor altered autonomic function during the recovery from the stressor. The two scenes were (a) nature (composed of trees, grass, fields) or (b) built (composed of man-made, urban scenes lacking natural characteristics) environments. Autonomic function was assessed using noninvasive techniques of heart rate variability; in particular, time domain analyses evaluated parasympathetic activity, using root-mean-square of success...