Using radioactive multitracers produced by RIKEN Ring Cyclotron, the adsorption of metal elements on hydrated ferric oxide, marine sediments (deep-sea and near-shore sediments) and clay minerals (montmorillonite and kaolinite) from artificial seawater was studied. The adsorption coefficients (K_ads) of Mg, Sc, V, Mn, Fe, Co, Ni, Zn, Ga, As, Se, Rb, Sr, Y, Zr, Nb, Mo, Tc, Ru, Rh, Pd, Ag, In, Sn, Eu, Gd, Tb, Tm, Yb, Lu, Hf, Re and Hg were determined. The order of K_ads for each element can be summarized as follows: hydrated ferric oxide>deep-sea sediment>montmorillonite/near-shore sediment/kaolinite. The observed relationships between log K_ads and the logarithm of the mean oceanic residence time indicate that adsorption of metal elements on marine particulate materials plays an important role in their removal from seawater.

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Iridium has been analyzed at nanogram levels in a geological sample by isotope dilution mass spectrometry employing inductively coupled plasma mass spectrometry (ICP-MS). It is well known that platinum group elements form strong anionic complexes, thus anion exchange resin was used for the preconcentration of Ir from sample matrix. Separation of Ir from elements in a complex matrix is problematic, as Ir(IV) is more efficiently extracted on the anion exchange resin than is the lower oxidation state of Ir. The total Ir content in a solution was oxidized to Ir(IV) using chlorinated lime as the oxidizing agent in order to enhance extraction of Ir on anion exchange resin in HCl medium. Its stripping was carried out with a mixture of HCl and HClO₄. Prior to extraction, the most important step in isotope dilution mass spectrometric analysis of Ir is to achieve complete isotopic homogenization of natural Ir with the enriched isotope ¹⁹¹Ir*. In this paper, we have described a method for the isotopic homogenization of Ir in solution by microwave digestion spanning over a period of 12h. The isotope ratio values obtained by ICP-MS are sufficiently precise and accurate; from them the concentration was computed. The method has been successfully applied to determine Ir in a Cretaceous-Tertiary boundary sample from Stevns Klint, Denmark.

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A spectral fitting method is described to analyze the ICP-AE spectrum of a crude rare-earth chloride obtained from a monazite ore. Each window for a rare-earth element (width, 1nm; 400 data) was successively analyzed using some developed software. The linear additivity of observed reference spectra of rare-earth elements in a spectrum database was assumed to synthesize a simulated spectrum, and differences between the simulated spectrum and an observed spectrum were minimized by a least-squares method which varies linear coefficients. Consequently, determined rare- earth elements (mass% of total rare-earth) were Y(0.42%), La(23.7%), Ce(45.5%), Pr(5.38%), Nd(19.8%), Sm(3.60%), Eu(0.011%0), Gd(1.17%), Tb(0.077%), Dy (0.26%), Ho(0.032%), Er(0.029%) and Yb(0.005%). Tm and Lu could not be determined due to weak line intensities. It took less than 2 min to analyze each window, when a personal computer equipped with an 80486 CPU was used. The obtained analytical results agreed well with those obtained by isotachophoresis- particle induced X-ray emission, confirming the utility of this method for such samples with heavy spectrum interference.

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The feasibility of coupling the isotope dilution (ID) analysis and the electrothermal vaporization/inductively coupled plasma mass spectrometry (ETV-ICP-MS) was studied in order to determine trace impurities on Si-wafer surface precisely. The precision of the isotope ratio measurement was investigated for single element and sequential two-element determination by ETV-ICP-MS. In the case of the single element determination, 0.1ng ml^-1 of Cu in a 20μl sample could be measured with relative standard deviation (RSD) less than 6%, and 1ng ml^-1 of Cu and Zn could be measured with RSD less than 5% in the sequential two-element determination. Coupling of ID and ETV-ICP-MS was applied to determine trace impurities of Cu, Zn and Pb, which were collected by etching a Si-wafer surface with a vapor mixture of nitric acid and hydrofluoric acid. The amount of etching solution obtained from one Si-wafer was about 200μl. Those impurities were determined at 3×10⁸-8.7×10⁹ atoms cm^-2 with an RSD of 2% by ID-ETV-ICP-MS. The amount of Cu on the Si-wafer surface was also determined by calibration method with ETV-ICP-MS and by graphite furnace atomic absorption spectrometry. The results obtained by these three different methods agreed well with each other.

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The formation of the trigonal-bipyramidal palladium(II) complexes with tris(2-diphenylphosphinoethyl)phosphine (pp3) and one solvent molecule, [Pd(pp3)(solvent)]²⁺ (solvent=acetonitrile, pyridine, dimethyl sulfoxide, N, N-dimethylformamide, trimethylphosphite), is confirmed by the ³¹P NMR spectroscopy. In these complexes, the central phosphorus atom in the pp3 ligand and the solvent molecule are coordinated in the axial position, and the terminal phosphorus atoms in the pp3 ligand are in the equatorial plane. The ³¹P NMR chemical shifts of the axial and equatorial phosphorus atoms are quite sensitive to the axially coordinated solvent. The σ and π donations of the solvents were characterized by using the ³¹P NMR chemical shifts.

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Europium(III) complexes with two series of β-diketonates and trioctylphosphine oxide (topo) have been synthesized and the fluorescence properties were studied. The β-dikatonate ligands used had the formula R₁COCHCOR₂ (I: R₁=2- naphthyl, R₂=CF₃, CF₂CF₃, CF₂CF₂CF₃, CF₂CF₂CF₂CF₃; II: R₁=2-phenanthryl, R₂=CF₃, CF₂CF₃, CF₂CF₂CF₃, CF₂CF₂CF₂CF₃, which are designated as NF₃, NF₅, NF₇, NF₉, PF₃, PF₅, PF₇ and PF₉, respectively). These complexes having the composition of [Eu(L)₃(topo)₂] (L=NF₃-NF₉, PF₃) and [Eu(L) ₃(topo)_1.5] (L=PF₅-PF₉) gave very strong fluorescence emission when excited by UV light (complexes of NF₃-NF₉, λ_{ex, max}=339nm, λ_{em, max}=615nm, PF₃, λ_{ex, max}=344nm, λ_{em, max}=615nm, PF₅-PF₉, λ_{ex, max}=346nm, λ_{em, max}=615nm). The ultra-violet spectra, fluorescence spectra, molar absorption coefficient (ε), fluorescence quantum yield (φ_f), and fluorescence lifetime (τ) of the complexes in benzene were measured. The results reveal tendencies for φ_f and the fluorescence absolute sensitivity (A.S=εφ_f) in the following order: φ_f, 2-naphthyl>2-phenanthryl(for an identical R₂); C₄F₉≥C₃F₇>C₂F₅>CF₃(for an identical R₁); A.S, PF₉>PF₇>NF₉≈NF₇>PF₅≈NF₅>NF₃>PF₃. The ¹H NMR signal of β-H in the β-diketonate ligand turns out to be a good measure to estimate φ_f; since the R₂ is more electron-withdrawing, the β-H chemical shift goes to a higher field and the fluorescence of the complex becomes more enhanced. The detection limit of the complex [Eu(L)₃(topo)_1.5] (L=PF₇) is 4.42×10^-12M (M=mol dm^-3).

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The complexation of 1, 4, 7, 10-tetraoxacyclododecane (12-crown-4) with sodium, potassium, rubidium, cesium and ammonium ions has been studied by titration calorimetry in N, N-dimethylformamide (DMF) and water containing 0.1mol dm^-3 (C₂H₅)₄NClO₄ and (C₂H₅)₄NCl, respectively, as constant ionic media at 25°C. A very small heat of complexation other than the heat of dilution of titrant was evolved in the course of the titration of sodium, potassium, rubidium, cesium and ammonium ions with 12-crown-4 in water; thus, the complexation of 12-crown-4 with these cations is expected to be very weak. The formation of [M(12-crown-4)]⁺ and [M(12-crown-4)₂]⁺ (M=Na⁺, K⁺, Rb⁺, Cs⁺) complexes was revealed in DMF, and their formation constants, reaction enthalpies and entropies were determined. On the other hand, no significant heat ascribable to complexation was liberated for the ammonium 12-crown-4 DMF solutions, and the formation of the ammonium 12-crown-4 complex was very weak, practically negligible. The cavity size of 12-crown-4 is 57pm in radius, while the alkali-metal ion has an ionic radius of 116-181pm. Since 12-crown-4 is too small to fully accommodate any alkali-metal ion, the formation of the [M(12-crown-4)]⁺ and [M(12-crown-4)₂]⁺ (M=Na⁺, K⁺ Rb⁺, Cs⁺) complexes results. The formation constants, enthalpies and entropies for the [M(12-crown-4)]⁺ (M=Na⁺, K⁺, Rb⁺, Cs⁺) complexes do not differ significantly by metal ions. Thus, in DMF, 12-crown-4 is not able to distinguish metal ions having different sizes.

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The X-ray power dependence of the charge-up shift of a photoelectron line was examined for metal films insulated from a spectrometer. As the X-ray power increased, the observed line position shifted to a higher binding energy, and approached an asymptotic value. This charge-up behavior was treated based on the balance between the photoelectron emission from the sample surface and electron injection from an aluminum window of the X-ray source and from other electron sources. It was concluded that, for insulated metals, the vacuum level of the sample is aligned to that of the spectrometer when the X-ray power is extrapolated to zero, i.e., the magnitude of the charge-up is equal to zero. The work function of the spectrometer was successfully determined with samples having a known work function. A new method to obtain the binding energy relative to the vacuum level for insulators is proposed.

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We explored optical trapping-spectrophotometry of ion-exchange polymer microparticles in water and, determined the dye (tris(2, 2′-bipyridine)ruthenium(II) complex; Ru²⁺) concentration adsorbed on an individual particle (diameter (d)=20-140μm). The absorbance of Ru²⁺ on the particle increased with an increase of the dye concentration in the aqueous phase, while it was essentially independent of d. The results indicate that adsorption of the complex takes place in the surface layer of the particle, but not homogeneously in the entire particle. A possible role of the optical trapping- spectrophotometry method in direct analyses of trace amounts of molecules concentrated on single microparticles in olution is discussed.

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Organic acids in aqueous solution were determined with a fiber-optic sensor having a chitosan/poly(vinyl alcohol) cladding. Interference from ethanol could be reduced by controlling the crosslinking of the cladding with glutaraldehyde and by modifying the cladding with 5′, 5"-dibromopyrogallolsulfonphthalein. The response time for 5v/v% acetic acid was within 1min and the RSD was ca. 2% for 10 successive measurements. Coating of the cladding with an amorphous fluoropolymer increased its durability and removed interferences from inorganic acids and non-volatile compound.

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The theory of the transient potential response of potentiometric ion-selective electrodes (J. Electroanal. Chem. Interfacial Electrochem., 378, 215 (1994)) is further elucidated. General solutions of the transient potential vs. time curves for a stepwise change in the activity (concentration) of a potential-determining ion in an external solution were numerically obtained for different cases concerning their ion-transfer kinetics. Also, the response time, defined as the time which is taken by the potential of an ion-selective electrode to change from its initial value to within a given limit of the final value, was numerically obtained, and is discussed in terms of the ion concentrations, the kinetic parameters of the ion-transfer reaction, and the electrical double layer capacity of the ion-selective electrode interface. Furthermore, the theory is extended so as to include the transient potential response of neutral-carrier-based ion-selective electrodes. The theory predicts the effect of the concentration of a neutral-carrier, which depends on the reaction mechanism of the carrier- assisted ion transfer across the interface.

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The effects of α-substituents on sodium-ion selectivities of bis(12-crown-4-methyl) malonates, which are highly selective for sodium ions, were investigated by incorporating various substituents with high lipophilicity, bulkiness, polarity and back strain. The incorporation of geminal substituents such as long alkyl chains and benzyl groups into the α-position of the malonate was found to generally enhance the Na⁺ selectivity, especially against K⁺, of the bis(12-crown-4) derivatives. The α, α′-dibenzylmalonate derivative gave the best Na⁺ selectivity of all the bis(crown ether)s designed here.

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An X-ray fluorescence method using the coprecipitation-preconcentration technique has been developed for simple determination of both acid-soluble and insoluble trace metal components, such as manganese, iron, nickel, copper and zinc in sea salts. A salt sample is dissolved in a nitric acid solution, and the residue is filtered off onto a membrane filter. After the pH is adjusted to 7-8, the filtrate is boiled, followed by addition of aluminum carrier, oxine and thionalide solutions. The solution is re-adjusted to pH 9, and kept at 80 -85°C for 60min. The precipitates are filtered off onto another membrane filter. X-Ray fluorescence intensities from two filters loaded with the residue and precipitates are measured and the concentrations of the elements are determined simultaneously using the calibration curves. Detection limits were 0.01μg g^-1 for manganese and copper, 0.04μg g^-1 for nickel and zinc, and 0.05μg g^-1 for iron, regardless of the soluble and the insoluble components. The present method was successfully applied to the analysis of sea salt samples.

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A sample was decomposed with boiling 6M hydrochloric acid in a helium stream in order to convert phosphorus, sulfur and arsenic into phosphine (PH₃), hydrogen sulfide and arsine (AsH₃), respectively, which were collected in a liquid- nitrogen cold trap. The trap was warmed at 80°C, and the three gases were then separated by gas chromatography on a Porapak QS column and detected with a photoionization detector. Phosphorus (0.3-2.2μg), sulfur (0.8-3.5μg) and arsenic (4-4.5μg) in steel were determined simultaneously with relative standard deviations of better than 7% (n=3 to 4) within 70min. The detection limits for phosphorus, sulfur and arsenic were 2, 280 and 4ng, respectively.

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A flow-injection (FIA) manifold is described for the simultaneous determination of potassium and sodium in samples of vegetables using flame emission spectrometry as the detection process. Two dialysis units were included so as to provide the system with a high dilution capacity (dilutions of about 600-700 fold), and also to allow bicomponent analysis: the same sample plug was divided between a donor and an acceptor stream that were subsequently directed to two detectors placed in parallel. The results of the FIA method were in good agreement with those of the reference procedures (relative deviations lower than 3%). Sampling rates from 120 to 150 samples per hour (corresponding to 240 to 300 determinations per hour) were achieved with relative standard deviations below 1.7%.

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An automated flow-injection analytical system, equipped with an immobilized _L-lysine-α-oxidase reactor (stable for over 6 months) and having a hydrogen peroxide electrode in the manifold, was developed for biosensing L-lysine. A substantial improvement in the selectivity for lysine was achieved by lowering the system temperature to 10°C; the sensor response was linearly dependent on the _L-lysine concentration (from tens of μM to mM order). The analytical results were verified by HPLC using protein hydrolyzates as test solutions comprising various interfering amino acids. By the aid of an in-line filter, the leaching of lysine from L-lysine-enriched fish feed into an aqueous buffer was automatically monitored.

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Biological samples containing glutathione (GSH) and glutathione disulfide (GSSG) were deproteinized by HClO₄ or metaphosphoric acid in the presence of bathophenanthroline disulfate. The total glutathione (GSH+2×GSSG) in the sample was determined using 5, 5′-dithiobis(2-nitrobenzoic acid) and glutathione reductase by the standard enzymatic recycles methods. GSH was determined as the difference between the concentration of the total glutathione and GSSG; GSSG was determined after blocking the thiol group of GSH with acrylonitrile. The method presented here is an improved version of that reported by Griffith (Anal. Biochem., 106, 207 (1980)) using 2-vinylpyridine as the modifying reagent. By using the present method, an analysis of GSH and GSSG is possible without exposure to any bad odor or the need to distill 2-vinylpyridine. In addition, this method was improved by a deproteinization procedure. Highly accurate results could be rapidly obtained by this method.

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Pure and modified polyethyleneimines with molecular weights of up to about 400 were characterized using gas chromatography (GC)/chemical ionization mass spectrometry (CI-MS) and GC with a flame ionization detector (FID). Relatively stable molecular ions produced by CI-MS provided information for identifying each polyethyleneimine homolog. FID-GC provided more accurate quantitative information on the distribution of the homologs identified by GC/CI-MS. The levels of various ethyleneamines, potential genotoxicants, could be simultaneously obtained by this approach, providing information used to evaluate the human safety of polyethyleneimines from various sources and synthetic routes.

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The state of carbonaceous components in coal fly ash fractionated by particle size and density was investigated by means of simultaneous thermal analysis-mass spectrometry in an inert atmosphere (He) and a quasi air atmosphere (O₂/He=20/ 80vol%). The carbonaceous components were characterized by their thermal degradation behavior and evolved gas species observed in each condition. Their components were proved to exist in three different states: the fractions with larger particle size (>20μm) and medium density (2.0-2.4g/cm³) mostly consist of elemental carbon, the smaller particle size fractions (<5μm) organic and elemental carbon, and the higher density fractions (2.8-3.2g/cm³) carbonate. In addition to the carbonaceous components, the existence of sulfate and hydroxide was suggested.

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The Cu(III)/Cu(II) content ratio of five YBa₂Cu₃O_7-x high-temperature (T_c, ca. 95K) superconductive materials prepared under various final heating conditions was determined by differential-pulse voltammetry in an alkaline-supporting electrolyte (0.01M NaOH). Samples were mixed into a carbon-paste electrode and deposited onto a glassy-carbon surface. A simple calculation method based on voltammetric recordings was used to evaluate the stoichiometric coefficient of oxygen, which is of major interest in the characterization of the physical (conductive and superconductive) properties of these compounds. The thus-obtained results were compared with those provided by classical iodometry. The influence of several instrumental and preparative analytical variables on the voltammograms were studied.

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