The study on a PVC membrane electrode for gemfibrozil

In this paper, a poly(vinyl chloride) (PVC) membrane electrode is prepared for gemfibrozil, 2, 2-dimethyl-5(2,5-xylyloxy) valeric acid, based on its ion pair complexes with hexadecyltrioctyl ammonium iodide (HTOA). The membrane composition of the electrode was optimized by using the sequential level elimination method for orthogonal experimental design. The electrode has a Nernstian response range from 2.5 X 10(-5) to 0.1 mol/l with an average slope of 55.3 mV/decade. The limit of detection is 7.1 X 10(-6) mol/l. The electrode responses were not affected by pH in the range 10.0-12.3. A Na2B4O7-Na2CO3 buffer of pH = 11.0 was selected as the background electrolyte solution for potentiometric measurements. The electrode was used for determining gemfibrozil in pharmaceutical preparations with satisfactory results.

Application of static and dynamic enclosures for determining dimethyl sulfide and carbonyl sulfide exchange in Sphagnum peatlands: Implications for the magnitude and direction of flux

A static enclosure method was applied to determine the exchange of dimethyl sulfide (DMS) and carbonyl sulfide (OCS) between the surface of Sphagnum peatlands and the atmosphere. Measurements were performed concurrently with dynamic (flow through) enclosure measurements with sulfur-free air used as sweep gas. This latter technique has been used to acquire the majority of available data on the exchange of S gases between the atmosphere and the continental surfaces and has been criticized because it is thought to overestimate the true flux of gases by disrupting natural S gas gradients. DMS emission rates determined by both methods were not statistically different between 4 and >400 nmol m−2 h−1, indicating that previous data on emissions of at least DMS are probably valid. However, the increase in DMS in static enclosures was not linear, indicating the potential for a negative feedback of enclosure DMS concentrations on efflux. The dynamic enclosure method measured positive OCS flux rates (emission) at all sites, while data using static enclosures indicated that OCS was consumed from the atmosphere at these same sites at rates of 3.7 to 55 nmol m−2 h−1. Measurements using both enclosure techniques at a site devoid of vegetation showed that peat was a source of both DMS and OCS. However, the rate of OCS efflux from decomposing peat was more than counterbalanced by OCS consumption by vegetation, including Sphagnum mosses, and net OCS uptake occurred at all sites. We propose that all wetlands are net sinks for OCS.

Solution-processable highly efficient yellow- and red-emitting phosphorescent organic light emitting devices from a small molecule bipolar host and iridium complexes

A bipolar transport compound, 2,5-bis(4-(9-(2-ethylhexyl)-9H-carbazol-3-yl) phenyl)-1,3,4-oxadiazole (CzOXD), incorporating both electron-and hole-transport functionalities, was synthesized and fully characterized by H-1 NMR, C-13 NMR, elemental analysis and mass spectrometry. Its thermal, electrochemical, electronic absorption and photoluminescent properties were studied

Multifunctional metallophosphors with anti-triplet–triplet annihilation properties for solution-processable electroluminescent devices

With the goal to provide organometallic triplet emitters with good hole-injection/hole-transporting properties, highly amorphous character for simple solution-processed organic light-emitting diodes, and negligible triplet-triplet (T-T) annihilation, a series of new phosphorescent cyclometalated Ir-III and Pt-II complexes with triphenylamine-anchored fluorenylpyridine dendritic ligands were synthesized and characterized. The photophysical, thermal, electrochemical and electroluminescent properties of these molecules are reported.

1,1 '-dimethyl-4,4 '-(propane-1,3-diyl)-dipyridinium tetrabromidocadmate(II)

In the cation of the title compound, (C15H20N2)[CdBr4], the dihedral angle between the two pyridine rings is 70.85 (5)degrees. An intermolecular pi-pi interaction between the pyridine rings [centroid - centroid distance = 3.900 (4) angstrom] is observed. The Cd-II atom has a distorted tetrahedral coordination.

Electrochemical corrosion behavior of cast Mg-Al-RE-Mn Alloys in NaCl solution

The electrochemical corrosion behavior of Mg-6Al-0.4Mn and Mg-6Al-4RE-0.4Mn (RE = Mischmetal) alloys is investigated in 3.5% NaCl solution. The results of corrosion process, polarization behavior, and electrochemical impedance spectroscopy of the alloys reveal that Mg-6Al-4RE-0.4Mn exhibits enhanced corrosion resistance. The addition of RE stabilizes the solid solution and modifies the passive film through a finer microstructure.

Low Cationic Proportion Ampholytic Polymer: Synthesis,Solution Properties and Interaction with Anionic Surfactant

Novel ampholytic terpolymer of N-vinylformamide (NVF), vinylamine (VAm) and sodium acrylate (NA) with low cationic proportion was obtained by hydrolyzing copolymer of NVF and NA (PNVFNA). Solution properties of the polymer were investigated by methods of turbidity and viscosity experiment. The effect of sodium dodecyl sulfate (SDS) on solution viscosity was also investigated. The results showed that the turbidity curves were bimodal, and pH 3.0 was determined as the isoelectric point (IEP).

Synthesis and Aqueous Solution Properties of Hydrophobically Modified Anionic Acrylamide Copolymers

In this investigation, hydrophobically modified polyacrylamide with low amounts of anionic long-chain alkyl was synthesized by the free radical polymerization in deionized water. This water-soluble copolymerization method is more convenient compared with the traditional micellar copolymerization methods. The copolymers were characterized using Fourier transform infrared, H-1 NMR, and the molecular weight and polydispersity were determined using gel permeation chromatography. The solution behavior of the copolymers was studied as a function of composition, pH, and added electrolytes. As NaCl was added to solutions of AM/C(11)AM copolymers or pH was lowered, the shielding or elimination of electrostatic repulsions between carboxylate groups of the C(11)AM unit lead to coil shrinkage.

Fabrication of Superhydrophobic Cellulose-Based Materials through a Solution-Immersion Process

An industrial waterproof reagent [(potassium methyl siliconate) (PMS)] was used for fabricating a superhydrophobic surface on a cellulose-based material (cotton fabric or paper) through a solution-immersion method. This method involves a hydrogen bond assembly and a polycondensation process. The silanol, which was formed by a reaction of PMS aqueous solution with CO2, Was assembled on the cellulose molecule surface via hydrogen bond interactions. The polymethylsilsesquioxane coatings were prepared by a polycondensation reaction of the hydroxyl between cellulose and silatiol. The superhydrophobic cellulose materials were characterized by FTIR spectroscopy, thermogravimetry, and surface analysis (XPS, FESEM, AFM, and contact angle measurements).