Development of a precolumn derivatization method for the determination of free amines in wastewater by high-performance liquid chromatography via fluorescent detection with 9-(2-hydroxyethyl)acridone

A simple, sensitive, and mild method for the determination of amino compounds based on a condensation reaction with fluorescence detection has been developed. 9-(2-Hydroxyethyl)acridone reacts with coupling agent N,N-carbonyldiimidazole at ambient temperature to form activated amide intermediate 9-(2-acridone)oxyethylcarbonylimidazole (AOCD). The amide intermediate (AOCD) preferably reacts with amino compounds under mild reactions in the presence of 4-(dimethylamino)pyridine (base catalyst) in acetonitrile to give the corresponding sensitively fluorescent derivatives with an excitation maximum lambda(ex) 404 mn and an emission maximum at lambda(em) 440 nm. The labeled derivatives exhibit high stability under reversed-phase conditions. The fluorescence intensities of derivatives in various solvents or at different temperatures were investigated. The method, in conjunction with a gradient elution, offers a baseline resolution of the common amine derivatives on a reversed-phase C-18 column. The LC separation for the derivatized amines shows good reproducibility with acetonitrile-water including 2.5% DMF as mobile phase. The relative standard deviations (n = 6) for each amine derivative are <4.5%. The detection limits (at a signal-to-noise ratio of 3) per injection were 0.16-12.8 ng/mL. Further research for the field of application, based on the AOCD amide intermediate as derivatization reagent, for the determination of free amines in real water samples is achieved.

High-performance dye-sensitized solar cells based on solvent-free electrolytes produced from eutectic melts

Low-cost excitonic solar cells based on organic optoelectronic materials are receiving an ever-increasing amount of attention as potential alternatives to traditional inorganic photovoltaic devices. In this rapidly developing field, the dye-sensitized solar cell(1) (DSC) has achieved so far the highest validated efficiency of 11.1% (ref. 2) and remarkable stability(3).

New Organic Sensitizer for Stable Dye-Sensitized Solar Cells with Solvent-Free Ionic Liquid Electrolytes

We report a high molar extinction coefficient metal-free sensitizer composed of a triarylamine donor in combination with the 2-(2,2'-bithiophen-5-yl)acrylonitrile conjugation unit and cyanoacrylic acid as an acceptor. In conjugation with a volatile acetonitrile-based electrolyte or a solvent-free ionic liquid electrolyte, we have fabricated efficient dye-sensitized solar cells showing a corresponding 7.5% or 6.1% efficiency measured under the air mass 1.5 global sunlight. The ionic liquid cell exhibits excellent stability during a 1000 h accelerated test under the light-soaking and thermal dual stress. Intensity-modulated photocurrent and photovolatge spectroscopies were employed along with the transient photoelectrical decay measurements to detail the electron transport in the mesoporous titania films filled with these two electrolytes.

Dye-sensitized solar cells with solvent-free ionic liquid electrolytes

We systematically studied the temperature-dependent physicochemical properties, such as density, conductivity, and fluidity, of 1,3-dialkylimidazolium iodides. In combination with the amphiphilic Z907Na sensitizer, we have found that it is important to use low-viscosity iodide melts with small cations to achieve high-efficiency dye-sensitized solar cells. By employing high-fluidity eutectic-based melts the device efficiencies considerably increased compared to those for cells with the corresponding state of the art ionic liquid electrolytes.

High-Performance Liquid and Solid Dye-Sensitized Solar Cells Based on a Novel Metal-Free Organic Sensitizer

A new metal-free organic sensitizer (see figure) for high-performance and applicable dye-sensitized solar cells is presented. In combination with a solvent-free ionic liquid electrolyte, a similar to 7% cell made with this sensitizer shows all excellent stability measured under thermal and light-soaking dual stress. For the first time a 4.8% efficiency is reached for all-solid-state dye-sensitized solar cells based oil all organic dye.

Surface-enhanced Raman scattering from surfactant-free 3D gold nanowire networks substrates

A useful method for the fabrication of three-dimensional gold nanowire networks based on the chemical reduction of HAuCl4 with trisodium citrate was presented. The coverage of the 3D gold nanowire networks was tunable by altering precursor concentration. The as-prepared 3D gold nanowire networks could be used as surface-enhanced Raman scattering (SERS) substrates and examined by 4-aminothiophenol (4-ATP) as a probe molecules.

Hydrothermal synthesis and thermoelectric transport properties of impurity-free antimony telluride hexagonal nanoplates

Impurity-free single-crystalline antimony telluride hexagonal nanoplates (see figure) are synthesized by a facile and quick hydrothermal treatment without any organic additives or templates. The inherent crystal structure is the driving force for the growth of these Sb2Te3 hexagonal nanoplates. Films of these nanoplates shows p-type behavior, and exhibit a promisingly high Seebeck coefficient of 425 mu V K-1 at room temperature.

Multifunctional label-free electrochemical biosensor based on an integrated aptamer

Aptamers, which are in vitro selected functional oligonucleotides, have been employed to design novel biosensors (i.e., aptasensors) due to their inherent selectivity, affinity, and their multifarious advantages over traditional recognition elements. In this work, we reported a multifunctional reusable label-free electrochemical biosensor based on an integrated aptamer for parallel detection of adenosine triphosphate (ATP) and alpha-thrombin, by using electrochemical impedance spectroscopy (EIS) and cyclic voltammetry (CV). A An electrode as the sensing surface was modified with a part DNA duplex which contained a 5'-thiolated partly complementary strand (PCS) and a mixed aptamer (MBA).

Sensitive, Label-Free Protein Assay Using 1-ethyl-3-methylimidazolium Tetrafluoroborate Supported Microchip Electrophoresis with Laser-Induced Fluorescence Detection

Based on the dimer-monomer equilibrium movement of the fluorescent dye Pyronin Y (PY), a rapid, simple, highly sensitive, label-free method for protein detection was developed by microchip electrophoresis with LIF detection. PY formed a nonfluorescent dimer induced by the premicellar aggregation of an anionic surfactant, SDS, however, the fluorescence intensity of the system increased dramatically when proteins such as BSA, bovine hemoglobin, cytochrome c, and trypsin were added to the solution due to the transition of dimer to fluorescent monomer. Furthermore, 1-ethyl-3-methylimidazolium tetrafluoroborate (EMImBF(4)) instead of PBS was applied as running buffers in microchip electrophoresis.

Template-free, surfactantless route to fabricate In(OH)(3) monocrystalline nanoarchitectures and their conversion to In2O3

In this work, a one-dimensional microrod-based three-dimensional flowerlike indium hydroxide (In(OH)(3)) structure was fabricated, without any templates or surfactants, using a well-known hydrothermal approach at a non-high temperature. In2O3 with similar morphology was formed by annealing In(OH)3 precursors and was characterized by Raman spectrum and photoluminescence (PL) spectrum in detail.

Improving performance of polymer photovoltaic devices using an annealing-free approach via construction of ordered aggregates in solution

Low crystalline order has been proved to be one of the main hindrances for achieving high performance devices based on thin films composed of crystallizable polymer. In this work, we use a facile method to substantially improve crystallinity of poly(3-hexylthiophene) (P3HT) in its pure or composite film via the construction of ordered precursors in the solution used for thin film deposition. These improvements have been confirmed by bright-field transmission electron micrography, electron diffraction, UV-Vis absorption and wide-angle X-ray diffraction.

Ag2S morphology controllable via simple template-free solution route

Different morphologies of Ag2S nano- and micro-materials, including spokewise micrometer bars, microfibers, nanowires, worm-like nanoparticles and nanopolyhedrons have been obtained controllably by a facile one-step method at room temperature. Powder X-ray diffraction (XRD), X-ray photo-electron spectroscopy (XPS) and scanning electron microscope (SEM) were employed to characterize the structure and compositions of those nanomaterials. Furthermore, ultraviolet visible (UV-vis) spectra of Ag2S with different morphologies show different spectral features.

Weak epitaxy growth of metal-free phthalocyanine on p-sexiphenyl monolayer and double-layer films

Weak epitaxy growth (WEG) can afford high-mobility thin films of disk-like organic semiconductor of which mobility is up to the level of the corresponding single crystals. We investigated the WEG behavior and mechanism of planar phthalocyanine in the model system of metal-free phthalocyanine (H2Pc) grown on p-sexiphenyl (p-6P) ultrathin films (monolayers and double layers). Highly oriented H2Pc films with molecules standing up exhibited two kinds of different in-plane orientations, i.e., three sets of in-plane orientations and only one set of in-plane orientation, on p-6P monolayer and double-layer films, respectively.

Rapid label-free detection of metal-induced Alzheimer's amyloid beta peptide aggregation by electrochemical method

Amyloid beta peptide plays a critical role in the pathogenesis of Alzheimer's disease (AD). Metal ions are highly enriched in cerebral amyloid deposits in AD and are proposed to be able to mediate A beta conformation. Therefore, a rapid, low-cost, and sensitive detection of metal-induced A beta aggregation and their relation to AD is clearly needed for the clinical diagnosis and treatment. In this report, we study metal-induced A beta aggregation by a rapid, label-free electrochemical method and monitor both the aggregation kinetics and the morphology in the absence or presence of Zn (II) and Cu (II).