Determination of 3-nitrobenzanthrone in surface soil by normal-phase high-performance liquid chromatography with fluorescence detection

A sensitive method for determining 3-nitrobenzanthrone in surface soil was developed. 3-Nitrobenzanthrone was reduced to 3-aminobenzanthrone by refluxing at 60 degrees C with hydrazine and Raney nickel for 20 min, and 3-aminobenzanthrone was determined by normal-phase high-performance liquid chromatography (HPLC) with fluorescence detection. We used a cyanopropyl stationary phase and an n-hexane-ethyl acetate (3:1, v/v) mobile phase, since 3-aminobenzanthrone exhibits fluorescence in a low-polarity solvent such as n-hexane or ethyl acetate, but not in a polar solvent such as water or methanol. The calibration graph showed good linearity (r2>0.9999) in the range of 0.002-2 ng, and the detection limit was 0.002 ng (S/N=3). 3-Nitrobenzanthrone in extracts from surface soil collected in the Chubu area (central area) of Japan was determined after clean-up using silica gel chromatography and high-performance liquid chromatography on a pyrenylethyl stationary phase. The concentration of 3-nitrobenzanthrone in surface soil was determined in the range of 1.2-1020 pg/g soil.     

Synthesis of micron-sized, monodisperse polymer particles of disc-like and polyhedral shapes by seeded dispersion polymerization

Micron-sized, monodisperse polymer particles having unique disc-like and polyhedral shapes were produced by seeded dispersion polymerization of various methacrylates with 1.57 m-sized polystyrene seed particles in the presence of saturated hydrocarbon droplets in methanol/water. Such nonspherical shapes were controllable by the polymerization conditions.Part CCLX of the series Studies on Suspension and Emulsion     

Synthesis of nanosized TiO2 particles in reverse micelle systems and their photocatalytic activity for degradation of toluene in gas phase

Nanosized pure TiO₂ particles with high crystallinity and large surface area were prepared by hydrolysis of tetrabutyl titanate in water/Triton X-100/isooctane reverse micelle solutions as reaction media followed by hydrothermal treatment to improve crystallinity. The prepared TiO₂ nanoparticles were characterized by XRD, BET, TGA, FT-IR and TEM. The size of ultrafine particles was controlled by changing the water content of the reverse micelle solution. The TiO₂ particles showed monodispersity, large surface area and high degrees of crystallinity and thermostability. The photocatalytic activity of the TiO₂ particles was evaluated by decomposition of toluene in the gas phase. The activity of the TiO₂ nanoparticles was higher than that of commercially available anatase fine particles, such as ST-01, which is one of the most active photocatalysts for degradation of organic compounds in the gas phase.     

On-line electrochemical detection of carbohydrates coupled with the periodate oxidation

A new concept of an amplified electrochemical detection of carbohydrates is proposed, where carbohydrates are oxidized by periodate ion (IO₄⁻) in acidic solutions to yield iodate ion (IO₃⁻) which would be electrochemically reduced into iodide ion (I⁻) under suitable conditions. This scenario allows highly sensitive detection of carbohydrates, for example, as 30 electrons per aldohexose molecule. Our cyclic voltammetric study revealed that IO₃⁻ is reduced at much lower overpotentials than IO₄⁻ at gold, platinum and carbon-based electrodes despite the fact that the standard redox potential of the IO₃⁻/I⁻ couple is more negative than that of the IO₄⁻/I⁻ couple. In the electrochemical reduction of IO₃⁻, I⁻ is considered to function as a mediator. Stable flow-through detection of IO₃⁻ in the presence of IO₄⁻ was realized at glassy carbon electrodes. This method was coupled with the IO₄⁻ oxidation of carbohydrates and the experimental conditions were partially optimized on a flow injection system. The IO₄⁻ oxidation-coupled electrochemical detection of carbohydrates was applied to ligand-exchange high-performance liquid chromatography in a post-column mode. Sub-nanomole order of carbohydrates were successfully detected on this system.     

Scandium-catalyzed carbon-carbon bond-forming reactions of 3-sulfanyl- and 3-selanylpropargyl alcohols

The scandium-catalyzed substitution reactions of the phenylsulfanyl and phenylselanyl propargyl alcohols 3a- i and 7a- h regioselectively proceeded to give the propargylated compounds 4 and 8 in high yields.     

[1,2‐Di­phenyl‐N,N′‐bis­(salicyl­idene)‐(RR,SS)‐1,2‐ethane­diyl­diamin­ato]­nitrido­manganese(V)

The title compound, [MnN(C₂₈H₂₂N₂O₂)], has a distorted square‐pyramidal coordination with an Mn[triple‐bond]N bond length of 1.516 (2) Å at the apical position. The five‐membered chelate ring adopts a gauche conformation with the two phenyl groups in equatorial orientations.