Spectroelectrochemical Analysis of Ion Transfer Mechanisms of Mitoxantrone at Liquid|Liquid Interfaces: Effects of Zwitterionic Dendrimer and Phospholipid Layer.

The ionic partition property and transfer mechanism of the anthraquinone antitumor agent mitoxantrone (MTX) were studied in detail at the water|1,2-dichloroethane (DCE) interface by means of surface-sensitive spectroelectrochemical techniques. The interfacial mechanism of the cationic MTX species was composed of potential-driven ion transfer and adsorption processes. The ion association between MTX and zwitterionic polyamidoamine (PAMAM) dendrimers with peripheral carboxy groups was also investigated in terms of the effects of pH and dendritic generation.

Selective determination of formaldehyde by high-performance liquid chromatography with porous graphitic carbon column using N,N'-bis(9-anthrylmethyl)propane-1,3-diamine as derivatizing reagent.

Aromatic compounds containing two secondary amino groups were designed and prepared as new derivatizing reagents for aldehydes. One of them, N,N'-bis(9-anthrylmethyl)propane-1,3-diamine (APD), could achieve selective determination of formaldehyde (FA) on a porous graphitic carbon (PGC) column using xylenes, chlorobenzene, and 1-chloronaphthalene as mobile phases by high-performance liquid chromatography (HPLC). The APD-FA derivative was eluted from the PGC column, while the other APD-aldehyde derivatives remained on the column during the HPLC measurements.

Tetraphenylantimony(V)-assisted transfer of hydroxide and fluoride anions across the 1,6-dichlorohexane | water interface.

The ion-transfer reaction at the 1,6-dichlorohexane (DCH) | water (W) interface in the presence of an organometallic cation, tetraphenylantimony (TPhSb), in DCH was studied voltammetrically. When TPhSb salt with [(CFSO)N] ion was added to the DCH-phase and the W-phase was buffered at pH < 6, a reversible cyclic voltammogram due to the simple transfer of TPhSb ion across the DCH | W interface was observed within the polarizable potential window. When the W-phase was buffered at pH > 7, the midpoint potential shifted to more positive potentials with increasing pH.

Spectroscopic Analysis of Apoferritin Associates with the Water-Soluble Porphyrins.

The association behavior of apoferritin species with the anionic porphyrins, 5,10,15,20-tetrakis(4-sulfonatophenyl)porphyrin (H TPPS ) and its zinc(II) complex (ZnTPPS ), which are water-soluble even in acidic solutions, was investigated for the first time through UV-Vis absorption and fluorescence spectroscopy in order to evaluate a potential ability of apoferritin as a stimuli-responsive molecular capsule. The absorption maximum wavelengths of both porphyrins were redshifted and the fluorescence intensity decreased, indicating the effective association between apoferritin species and the porphyrins, although it depended on the pH adjustment procedure. At pH 2, the ZnTPPS associated with apoferritin subunits without demetallating and protonating, while the free base porphyrin formed the J-aggregate of the diprotonated species (H TPPS ) , with extremely low fluorescence.

Photoinduced Electron Transfer of PAMAM Dendrimer-Zinc(II) Porphyrin Associates at Polarized Liquid|Liquid Interfaces.

The heterogeneous photoinduced electron-transfer reaction of the ion associates between NH2-terminated polyamidoamine (PAMAM) dendrimers and 5,10,15,20-tetrakis(4-sulfonatophenyl)porphyrinato zinc(II) (ZnTPPS(4-)) was studied at the polarized water|1,2-dichloroethane (DCE) interface. The positive photocurrent arising from the photoreduction of ZnTPPS(4-) by a lipophilic quencher, decamethylferrocene, in the interfacial region was significantly enhanced by the ion association with the PAMAM dendrimers. The photocurrent response of the dendrimer-ZnTPPS(4-) associates was dependent on the pH condition and on the generation of dendrimer.

Communication: Coordination structure of bromide ions associated with hexyltrimethylammonium cations at liquid/liquid interfaces under potentiostatic control as studied by total-reflection X-ray absorption fine structure.

Total-reflection X-ray absorption fine structure (TR-XAFS) technique was applied for the first time to an interface between two immiscible electrolyte solutions under potentiostatic control. The hydration structure of bromide ions was investigated at polarized 2-octanone/water interfaces. TR-XAFS spectra at Br K-edge measured in the presence of hexyltrimethylammonium bromide (C6TAB) were slightly modified depending on the Galvani potential difference (Δ(o)(w)φ).

Spectroelectrochemical characterization of dendrimer-porphyrin associates at polarized liquid|liquid interfaces.

Molecular encapsulation of anionic porphyrins in NH2-terminated polyamidoamine (PAMAM) dendrimers and the interfacial behavior of the dendrimer-porphyrin associates were studied at the polarized water|1,2-dichloroethane (DCE) interface. Formation of the ion associates was significantly dependent on the pH condition and on generation of dendrimers. 5,10,15,20-Tetrakis(4-sulfonatophenyl)porphyrin (ZnTPPS(4-)) associated with the positively charged fourth-generation (G4) PAMAM dendrimer was highly stabilized in acidic aqueous solution without protolytic demetalation in a wide range of pH values (pH > 2).

Development of a GC-MS system with an array detector system for endocrine disruptor analysis.

A mass spectrograph using a position sensitive detector was designed and constructed. It has an image contractor lens system and a zoom lens system. The position sensitive detector consists of a micro channel plate (MCP) and a charge-coupled device (CCD).