Octyl(phenyl)-N,N-diisobutylcarbamoylmethyl phosphine oxide (CMPO) dissolved in an ionic liquids, 1-butyl-3-methylimidazolium hexafluorophosphate, greatly enhances extractability and selectivity of lanthanide cations compared to that dissolved in conventional organic solvents; further, the recovery of lanthanides extracted into ionic liquids can be accomplished using several stripping solutions containing complexing agents. The possibility of utilizing ionic liquids as novel separation media in an industrial liquid-liquid extraction process was demonstrated.

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Dopamine may show some biological activities in antitumor and cell apoptosis. Herein, we attempted to employ UV-Vis, CD, and electrochemical methods to investigate the interaction between DNA and dopamine. Both the spectroscopic and electrochemical evidence indicated that dopamine, which was a cation, could interact with polyanion DNA. However, this kind of interaction, mainly by a static electronic force, did not result in any damage of the DNA structure. This situation was quite different when Cu ion was added to the dopamine-DNA system; an obvious change in the color of the solution and in the spectra of UV-Vis and CD showed that some chemical changes occurred in this system, and that the DNA native structure was destroyed. The results of gel electrophores further revealed that DNA might be broken into small segments by dopamine in the presence of Cu ion. The possible reaction mechanisms are discussed.

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In this study, we developed a rapid, simple and homogeneous human recombinant estrogen receptor-β(hrER-β) binding assay method using fluorescence polarization (FP) by applying a fluorescent ligand, fluorescein-labeled estradiol (F-E2). A Scatchard plot and a Hill plot analysis of the saturation binding assay using F-E2 and hrER-β were studied. F-E2 showed a high affinity for hrER-β, the dissociation constant was 5.53 nM, indicating that F-E2 is applicable to the hrER-β binding assay. Competitive binding assays using F-E2, in which the FP values decreased upon the addition of compounds (competitors) were carried out to evaluate the binding characteristics of compounds with and without biological activities to hrER-β. Twenty-one compounds, such as hormones, pharmaceuticals, industrial chemicals and phytoestrogens, were examined. The obtained sigmoidal inhibition curves were transformed into pseudo-Hill plots and the concentrations at 50% inhibition (IC₅₀) and Hill coefficients, the degree of cooperativity in ER-ligand binding, were obtained from the regression equations. Antagonists exhibited larger Hill coefficients than agonists, showing the correlation between the Hill coefficients and the estrogenic/antiestrogenic activities.

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Vacuum ultraviolet single-photon ionization time-of-flight mass spectrometry (VUV-SPI-TOFMS) has been applied for the detection of chlorobenzene, o-dichlorobenzene, and o-chlorophenol as surrogates for polychlorinated dibenzo-p-dioxine/furans (PCDD/F). The photoionization mass spectra of these compounds appear to be fragmentation free in the ionization processes by the VUV-SPI at 10.2 eV (121.6 nm). Quantum chemical calculations support no fragmentation in the photoionization of chlorobenzene derivatives at around 10 eV. The absolute photoionization cross-sections of chlorobenzene, o-dichlorobenzene, and o-chlorophenol were estimated at 10.2 eV. The photoionization cross-section is an important parameter in the detection of chlorobenzene derivatives by the single-photon ionization technique. The detection limit for chlorobenzene is on the order of tenth parts-per-billion volume (ppbv) in the present experimental setup.

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The surface activity of xanthine (Xan) and xanthosine (Xano) at a hanging mercury drop electrode (HMDE) was studied using out-of-phase ac and cyclic dc voltammetry. The results show that Xan and Xano were strongly adsorbed and chemically interacted with the charged mercury surface, which is the prerequisite step for applying the cathodic adsorptive stripping voltammetric determination of such biologically important compounds. Differential pulse cathodic adsorptive stripping voltammetry (DPCASV) and square-wave cathodic adsorptive stripping voltammetry (SWCASV) were applied for the ultratrace determination of Xan and Xano compounds. Moreover, a rapid and sensitive controlled adsorptive accumulation of Cu(II) complexes of both compounds provided the basis of a direct stripping voltammetric determination of such compounds to submicromolar and nanomolar levels. Operational and solution conditions for the quantitative ultratrace determination of Xan and Xano were optimized in absence and presence of Cu(II). The calibration curve data were subjected to least-squares refinements. The effects of several types of inorganic and organic interfering species on the determination of Xan or Xano were considered.

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A nitrate-selective electrode based on a recently synthesized bis(2-hydroxyanil)acetylacetone lead(II) complex [(haacac)Pb] has been developed. Among different compositions studied, a membrane containing 30.7% poly(vinyl chloride) (PVC), 61.3% dibutyl phthalate (DBP) as a plasticizer, 3% methyltrioctylammonium chloride (MTOAC) as a cationic additive and 5% ionophore (all w/w) exhibited the best potentiometric response toward nitrate ion in aqueous solutions. The potentiometric response of the electrode was linear with a Nernstian slope of -58.8 mV decade^-1 within the NO₃- concentration range of 2 × 10^-5 - 1 × 10^-1 mol dm^-3. The response time of the electrode was ≤ 10 s over the entire linear concentration range of the calibration plot. The electrode is suitable for use within the pH range of 5.3 - 11. The selectivity coefficients for the proposed electrode were improved for some interferences, when compared with those of commercially available nitrate-selective electrodes.

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A cobalt(II) derivative was used as a suitable ionophore for the preparation of a polymeric membrane nitrite-selective electrode. The electrode reveals a Nernstian behavior over a very wide NO₂- ion concentration range (1.0 × 10^-6 - 1.0 × 10^-1 M) and a very low detection limit (5.0 × 10^-7 M). The potentiometric response is independent of the pH of solution in the pH range 4.0 - 9.5. The electrode shows advantages such as low resistance, fast response and, most importantly, good selectivity relative to a wide variety of inorganic and organic anions. In fact, the selectivity behavior of the proposed NO₂- ion-selective electrode shows great improvements compared to the previously reported electrodes for nitrite ion. The proposed electrodes could be used for at least 2 months without any significant changes in potentials. The electrode was successfully applied to the determination of nitrate ion concentrations in sausage and milk samples.

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A spectrophotometric method for the determination of ionic surfactants with Bromophenol Blue (BPB) based on incorporation into a precipitated chitosan was studied. Cationic surfactants (CS⁺), such as a quaternary ammonium ion containing a long-chain alkyl group, associate with BPB^2- buffered at about pH 9 to form the ion associate (CS⁺)₂·BPB^2-. CS⁺ associates with anionic surfactants (AS^-). In the presence of a definite amount of CS⁺, an increase in the amount of AS^- leads to a decrease in the amount of excess CS⁺, and therefore to a decrease in the amount of the ion associate of CS⁺ with BPB^2-. The addition of a chitosan dissolved in acetic acid to a solution containing these ion associates leads immediately to precipitation of the chitosan and the incorporation of the ion associates (CS⁺)₂·BPB^2- or CS⁺·AS^- into the precipitated chitosan. After centrifuging, ionic surfactants can be determined by the following two methods: (1) the absorbance of the supernatant solution is measured at 590 nm. (2) After the supernatant solution is separated, the precipitate is dissolved in an acetic acid solution and the absorbance is measured at 625 nm. Because the color of the precipitate is judged by the naked eye, this can be applied to the visual method. This is a simple and rapid method for the determination of a 10^-6 M order of ionic surfactants.

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A selective, sensitive, rapid and simple-handling analytical method for the determination of cyanide at low detection limits in surface and underground water, soil and industrial waste samples was developed. The method is based on a reaction, proposed by Guilbault and Kramer, where free cyanide reacts with p-nitrobenzaldehyde to form an intermediate cyanohydrin, which reacts with o-dinitrobenzene to give a highly colored purple compound. The original procedure was modified for application in a small device containing a gas-permeable membrane. The cyanide is converted in the volatile hydrogen cyanide, which permeates through a PTFE membrane, reaching colorimetric reagents. In order to obtain semi-quantitative results, printed color scales were built. The method allows rapid, accurate, selective, low-cost and simple-handling determinations of free cyanide, even in complex samples. About 150 real samples were analyzed. Less than 10 ng of free cyanide per ml (10 μg l^-1) can be easily detected. For more concentrated solutions, the results had been compared to those obtained using differential pulse polarography. The standard addition method was used for more diluted solutions.

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A chemiluminescence (CL) method using flow injection (FI) has been investigated for the rapid and sensitive determination of enalapril maleate. The method is based on the CL reaction of the drug with tris(2,2′-bipyridyl)ruthenium(II), Ru(bipy)₃²⁺ and acidic potassium permanganate. After selecting the best operating parameters, calibration graphs were obtained over concentration ranges of 0.005 - 0.2 μg/ml and 0.7 - 100 μg/ml with a detection limit (S/N = 2) of 1.0 ng/ml. The average % found was 99.9 ± 0.7 and 100.2 ± 0.3 for the two concentration ranges respectively. %RSD (n = 10) for 5.0 μg/ml was 0.44. The method was successfully applied to the determination of enalapril maleate in dosage forms and biological fluids without interferences.

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Controlled-pore silica glass modified with N-propylsalicylaldimine (SCPSG) has been investigated as a surface-active matrix for the separation of some metal ions. The porous silica glass base was confirmed to have better stability towards hydrolysis in aqueous solution buffered at pH = 9 in comparison to silica gel, which showed twice the surface area of controlled-pore silica glass. The different analytical parameters affecting the batch mode separation and preconcentration of trace Al(III), Ag(I) and Hg(II) in environmental samples using SCPSG, prior to their determination using inductively coupled plasma mass spectrometry (ICP-MS), were studied. The optimum conditions are pH 9.0 &plesmn; 0.1, time of stirring 30 min and the eluent concentration 0.5 mol dm^-3 HNO₃. The ion-exchange capacity of SCPSG with respect to Al(III), Ag(I) and Hg(II) was 0.27, 0.18 and 0.23 mmol g^-1, respectively. The recovery values for the metal ions were 96.8 ± 0.86, 98.1 ± 0.60 and 96.2 ± 1.06%, and the analytical detection limits were 26.1, 1.49 and 0.44 pg cm^-3, respectively, for a preconcentration factor of 100. The method has been applied to the determination of the investigated metal ions in natural water samples as well as certified and reported samples and the results were found to be accurate.

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The enantiomers of fourteen O,O-dialkyl-2-benzyloxycarbonyl-aminoarylmethyl-phosphonates are directly separated on the tris(3,5-dimethylphenylcarbamate) cellulose column (Chiralcel OD-R) under reversed phase mode. The results of the chiral separation are different from the results obtained in the normal phase mode. The mobile phase plays an essential role in chiral discrimination when using Chiralcel OD-R. The influences of the mobile phase composition on the retention and the enantioselectivity are investigated. The influences on chiral separation of the length and steric hindrance of alkoxy groups of the phosphonate ester and of the nature of the substituent on the benzene ring that is attached to the chiral carbon atom are also discussed.

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A simple and reliable high-performance liquid chromatographic (HPLC) method was developed for the simultaneous determination of five hydroxyanthraquinones (aloe-emodin, rhein, emodin, chrysophanol, and physcion) in Rhubarb and experimental animal bodies. A Zorbax SB-C18 column (250 mm × 4.6 mm i.d., 5 μm) and a methanol -0.5% acetic acid (85:15, v/v) mobile phase were used for the separation. The detection wavelength of a diode array detector (DAD) was set at 254 nm. Regression equations revealed a linear relationship (R² > 0.9996) between the mass of hydroxyanthraquinones injected and the peak areas detected by DAD. The detection limits (S/N = 3) ranged from 0.35 ng to 3.13 ng, and the recoveries ranged from 83% to 103% for different hydroxyanthraquinones. This method is simple, sensitive and suitable for the analysis of hydroxyanthraquinones in medicinal materials and pharmacological experiment samples.

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Titanium dioxide nanoparticle dynamically loaded with 8-hydroxyquinoline (nanometer TiO₂-Oxine) was used as a solidphase extractant for the preconcentration of trace amounts of aluminum(III) and chromium(III) prior to their determination by inductively coupled plasma atomic emission spectrometry (ICP-AES). The optimal conditions for preparing nanometer TiO₂-Oxine were obtained. Also, the separation/preconcentration conditions of analytes, including the effects of the pH, the sample flow rate and the volume, the elution solution and the interfering ions on the recovery of the analytes were investigated. At pH 6.0, the adsorption capacity of nanometer TiO₂-Oxine was found to be 5.23 mg g^-1 and 9.58 mg g^-1 for Al(III) and Cr(III), respectively. An enrichment factor of 50 was achieved by this method, and the detection limits (3σ) for Al(III) and Cr(III) were 1.96 and 0.32 μg L^-1 respectively. The proposed method was applied for the determination of trace Al(III) and Cr(III) in biological samples and lake water with satisfactory results.

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A novel spectrophotometric method has been developed for the determination of proteins using the p-acetychlorophosphonazo (CPA-pA)-barium(II) complex as a spectroprobe. In the pH range of 2.0 - 2.8, the absorbance of the CPA-pA-barium(II) complex at 649 nm is greatly decreased by protein. The absorbance decrease is in proportion to the concentration of protein in the range of 0 - 20 mg/L. The apparent molar absorptivities are 1.56 × 10⁶, 1.70 × 10⁶ and 6.04 × 10⁵ L mol^-1 cm^-1 for bovine serum albumin (BSA), human serum albumin (HAS) and ovalbumin (OVA), respectively. The method is reproducible and simple, and has been used to determine total protein in human sera. The results are in agreement with those obtained by the pyrocatechol violet (PV)-Mo(VI) method, with relative standard deviations of 2.5 - 3.5% (n = 6).

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An X-ray crystallographic study demonstrated that the tris complex of Al³⁺ with 2-methyl-8-quinolinol (Hmq), [Al(mq)₃], had a discrete octahedral geometry in a meridional configuration with respect to mq^- the Al-N bonds were appreciably elongated. In organic solvents, the complex reacted with water to give a lower species of a μ-oxo dimer, [Al₂O(mq)₄], and a protonated ligand, depending on the concentrations of water and of excess ligand. None of Cl^- Br^- I^- ClO₄^-, and CH₃COO^- showed any reactions with [Al(mq)₃]. The anions having high affinities to Al³⁺, such as H₂PO₄^- and F^- replaced all the ligand. The anion having a lower affinity, HSO₄^-, exclusively formed a mixed-ligand complex of [Al(mq)₂HSO₄], which had a more intense fluorescence than the others. In contrast, the corresponding 8-quinolinol (Hq) complex, [Alq₃], showed no reactions with any anions.

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Cationic liposomes composed of two components, diethylaminoethyl-carbamoyl cholesterol and phosphatidylcholine, were applied to an enhancer for a firefly bioluminescent (BL) assay of bacterial ATP in the presence of an ATP extractant. Trichloroacetic acid (TCA), which inhibits the activity of luciferase, was used as an ATP extractant. Cationic liposomes enhanced the BL intensity as long as luciferase was active. The detection limits for cell numbers of Escherichia coli extracts in the presence of cationic liposomes and in water alone were 199 and 897 colony forming units ml^-1, respectively. The sensitivity for bacterial ATP in the presence of cationic liposomes was improved by a factor of 2.5 times compared to that in the presence of diethylaminoethyl-dextran.

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The performance of octahydroxycalix[4]arene derivative used as a neutral carrier for silver polymeric membrane electrode was studied. The sensor gave a good Nernstian response of 58 ± 1 mV per decade for silver ion in the activity range 3.3 × 10^-6 to 3.3 × 10^-2 M Ag⁺. The limit of detection reached 2.1 × 10^-6 M Ag⁺ and exhibited high selectivity for silver ion against the alkali, alkaline earth and transition metal ions. The sensor can be used in wide pH range from 1.5 to 6.5. The response time of the sensor is less than 20 s. The potentiometric sensor was used as the indicator electrode in the titration of Ag⁺ ions by sodium chloride solution.

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We discovered novel calibrants, several 2,2,6,6-tetraalkylpiperidinyl derivatives, for accurate mass measurements by electrospray ionization mass spectrometry (ESI). These compounds showed excellent performance as internal calibrants for the accurate mass measurement in ESI-MS, without problems arising from differences in the ionization efficiencies between the analytes and calibrants.

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A simple HPLC method for the determination of imidazole antimycotics in cosmetic antidandruff formulations has been developed. HPLC was carried out on a Discovery RP-Amide C16 column and spectrophotometric detection was performed at 220 nm. The initial mobile phase was a mixture of acetonitrile and aqueous 10^-3 M NaClO₄ (pH 3.0) in the ratio of 15:85 (v/v); then a linear gradient up to 46% acetonitrile in 70 min, and up to 50% in 80 min. The extraction procedure has been validated by analyzing samples of shampoo and lotion spiked with 1% of the active principles. The recoveries were greater than 95% and the reproducibility was within 3%.

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The association between anionic water-soluble porphyrin and aromatic heterocyclic bases has been investigated to demonstrate the usefulness of a new in situ UV-VIS monitoring method of hydrothermal reactions. Spectral and absorbance changes in the presence of bases were possible to be detected by the new method at temperatures up to 150°C. The association constants (K_ass,₁) were determined from the absorbance-base concentration curves. The logarithmic values of K_ass,₁ were proportional to the number of rings of the bases, but this relationship became ambiguous beyond 100°C. This fact indicates that stacking between porphyrin and bases does indeed become weak at high temperatures.

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A chemiluminometric flow-through sensor for the simultaneous determination of glucose (Glu) and 3-hydroxybutyrate (HB) in a single sample has been developed. Coimmobilized 3-hydroxybutyrate dehydrogenase/NADH oxidase/peroxidase, a support material, and coimmobilized glucose dehydrogenase/NADH oxidase/peroxidase were packed sequentially in a transparent PTFE tube. The tube was then placed in front of a photomultiplier tube as a flow cell. A two-peak recording was obtained by one injection of the sample solution. The peak heights of the first and second peaks were dependent on the concentrations of HB and Glu, respectively. The calibration graphs for HB and Glu were linear at 0.05 - 10 and 0.1 - 30 μM, respectively. The maximum sample throughput was 30 h^-1. The sensor was stable for two weeks.

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A simultaneous determination with UV detection/capillary electrophoresis for Fe(II) and Fe(III) was achieved using a sulfonated bathophenantholine and desfferioxamine B. When the electrophoretic buffer was 60 mmol l^-1 SDS, 10 mmol l^-1 acetic acid (pH 4.0) and 10 mmol l^-1 ascorbic acid and at -10 kV, the iron(II) and iron(III) could not only be completely separated, but also be sensitively determined.

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Intraparticle mass transfer processes of Phenol Blue (PB) in single octadecylsilyl (ODS)-silica gel microparticles in acetonitrile-water were analyzed by microcapillary manipulation and microabsorption methods. An absorption maximum of PB, the sorption isotherm parameters, and the sorption rate in the microparticle system were highly dependent on the percentage of acetonitrile in solution. The results are discussed in terms of the microscopic polarity surrounding PB in the ODS phase and the relationship between the isotherm parameters and the sorption rate.

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Multielements in a typical Japanese diet certified reference material prepared at the National Institute for Environmental Studies (NIES) of Japan, in collaboration with the National Institute of Radiological Sciences (NIRS) of Japan were determined by instrumental neutron activation analysis (INAA). Five samples (ca. 510 - 1000 mg) and comparative standards were irradiated for a short time (10 s) at a thermal neutron flux of 1.5 × 10¹² n cm^-2 s^-1 (pneumatic transfer) and for a long time (6 h) at a thermal neutron flux of 3.7 × 10¹² n cm^-2 s^-1 (central thimble) in the Rikkyo University Research Reactor (TRIGA Mark-II, 100 kW). The irradiated samples were measured by conventional γ-ray spectrometry using a coaxial Ge detector, and by anti-coincidence and coincidence γ-ray spectrometry with a coaxial Ge detector and a welltype NaI(Tl) detector. The concentrations of 38 elements were determined by these methods.

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Crystals of C.I. Disperse Blue 354, a commercial methine disperse dye, were grown from an ethyl acetate and the crystal structure was determined. Results show that two aromatic planes are effectively coplanar with the dihedral angle of 10.61(11)°. The dicyanomethylene group is slightly twisted and two n-hexyl groups tend to be separated with one alkyl group being at the level of the aromatic plane, and another one below it. The intermolecular hydrogen bonds and the interlayer π-π stacking stabilize the crystal packing.

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The title compound crystallizes triclinically in space group of P1 The C₂-COOH and C₃-COOH molecular groups are planar. The crystal structure is stabilized by the formation of intermolecular (O-H···O) hydrogen bonds.

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Chiral, non-racemic hexahydro-oxazolo[3,2-a]pyridin-5-ones are strategic starting materials for the asymmetric synthesis of alkaloids, via the stereoselective C-C bond formation at the position α to the nitrogen atom. The stereoselectivity of this key step is mainly driven by the geometry of the fused rings of the oxazolopyridine moiety. In this work, the synthesis and X-ray structure of trans(3R,2aS)-(—)-3-phenyl-hexahydro-oxazolo[3,2-a]pyridin-5-one is reported.

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The structure of the dinuclear complex [Pt₂I₄(TEPOP)₂] (TEPOP = tetraethyldiphosphite) was determined by X-ray diffraction. The two platinum atoms are doubly bridged by two (EtO)₂POP(OEt)₂ ligands and constitute an eightmembered ring. The platinum atoms have a square-planar geometry, which are completed by two phosphorous and two iodine atoms in a mutually cis arrangement.

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C₁₁H₁₂O₂Se is triclinic, P1. Unit-cell dimensions at 293 K are a = 5.8450(10), b = 8.1490(10), c = 11.4620(10)Å, α = 97.050(10), β = 90.140(10), γ = 90.120(10)°, V = 541.81(12)ų, Dx = 1.564 g/cm³, and Z = 2. The R value is 0.047 for 1388 observed reflections. The dihedral angle between the phenyl ring and the isobutenyl group is 72.3(2)°. There is an intermolecular hydrogen bond between two symmetry-related carbonyl groups with an O1···O2 distance of 2.669(6)Å The molecules in the crystal are packed at normal van der Waals distances.

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