The mechanism for extracting bismuth(III) from an HNO₃ aqueous solution into a trioctylmethylammonium nitrate (TOMA•NO₃) xylene solution was studied at 25°C. The distribution ratio of bismuth(III) was measured as functions of the bismuth(III) concentration and the HNO₃ concentration in aqueous solution, and the TOMA•NO₃ concentration in xylene. By taking into consideration the dimerization of TOMA•NO₃ in xylene, the extraction equilibrium of bismuth(III) from nitric acid was determined to be Bi³⁺_aq+3NO^-_{3, aq}+1.5(TOMA•NO₃)_{2, org}•<K_ex>(TOMA⁺)₃•Bi(NO₃)^3-_{6, org}. The conditional extraction constant from 1M H₂SO₄ was obtained as log K_ex=4.2.

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The extraction of copper(II) with benzoic acid using chloroform, benzene, 1-octanol, and 2-octanone as a solvent was carried out at 25°C and at an aqueous ionic strength of 0.1mol dm^-3 (NaClO₄). Copper(II) has been found to be extracted in any of these solvents as monomeric and dimeric copper(II) benzoates though the extent of dimerization of copper(II) benzoate differs from one another. The ease of the extraction was according to the order: chloroform>1- octanol>2-octanone>benzene; thus, chloroform is superior to the other solvents. In extraction using benzene the emulsion appeared even in the lower percent of the extraction region. The superiority of chloroform over the other solvents can be attributed to the low polarity and moderate solvating ability of chloroform, as well as the low solubility of water in it.

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The distribution coefficient (K_D) for twenty kinds of N-benzoyl-N-phenylhydroxylamine (BPHA) derivatives between chloroform or benzene and the aqueous phase was determined. A linear correlation was obtained between log K_D and the number of carbon atoms containing substituent groups for a series of alkyloxy derivatives. However, the data for those having a series of alkyloxy groups, and others having a straight or branched alkyl chain, fall on two independent lines in plots of log K_D vs. the van der Waals volume of the BPHA derivatives. From these results, the empirical contribution values (π_x), defined asπ_x=log K_D(X)-log K_D(H) {K_D(H) is the distribution coefficient of a parent compound and K_D(X) that of a derivative}, of the functional group to the distribution coefficient (log K_D), were as follows: 0.54 in a chloroform/ water system and 0.49 in a benzene/water system for the methyl and methylene groups, 0.30 in a chloroform/water system and 0.27 in a benzene/water system for the methoxy group, and -0.23 in a chloroform/water system and -0.12 in a benzene/water system for the nitro group, respectively. The utility of the contribution values (π_x) for the methyl, methylene, methoxy and nitro groups was verified for estimating the distribution coefficient (K_D) of the BPHA derivatives.

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A collection and elution method for anionic metal chelate on protonated chitin has been applied to the spectrophotometric determination of iron. Iron is collected as its anionic 8-hydroxyquinoline-5-sulfonate (8-HQ-5-S) chelate on a column of chitin in weak acidic medium. The iron(III)-8-HQ-5-S chelate collected on the chitin is effectively eluted with a small volume of 0.1mol dm_-3 ammonia buffer solution (pH 9), and the absorbance of the eluent is measured at 571nm. Beer′s law is obeyed over the concentration range of 0.5 to 5μg of iron in 1cm₃ of the eluent. Some metal ions and common inorganic anions do not interfere in concentration range of 100 to 1000 times that of iron, but the tolerance limit for Co, Ni and Cu is low due to the competitive reaction with 8-HQ-5-S. The present method can be applied to the determination of iron in tap and spring water samples.

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Voltammetric measurements were performed for the transfers of Li⁺ and Na⁺ at an oil/water interface facilitated by neutral ionophores including 14-crown-4 derivatives. For the organic solvent, nitrobenzene, o-nitrophenyloctylether (NPOE) and o-nitrophenylphenylether (NPPE) were examined. The interface between water and NPPE containing 20mM dibenzyl-14-crown-4 was found to serve best for the ion-selective-electrode (ISE) surface for the voltammetric determination of Li⁺. A test of this voltammetric Li⁺-ISE using artificial serum showed that the interference from a large amount (ca. 140mM) of Na⁺ in blood can be easily avoided by detecting the Na⁺ concentration simultaneously with the same electrode.

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Linear polystyrene, having a trimethoxysilyl group at one side of the terminal group, was newly synthesized and readily grafted onto porous silica gels using the terminal reactive group. Its packed column showed good selectivity based on the π-π interaction for polyaromatics as well as the usual reversed-phase mode separation for alkyl compounds. The elution behavior (including the elution order) agreed with those that were observed in non-silica-supported poly(styrene- divinylbenzene) spherical particles. However, the asymmetric factor (A_s) of the elution peaks for polyaromatics was much better in silica-supported polystyrene than in non-supported polystyrene; for example, the values of A_s for triphenylene were 1.4 and 4.7, respectively. This difference is attributable to the flexibility of the polystyrene chain.

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Bovine serum albumin (BSA) was evaluated as a fluorescence enhancement reagent using 41 fluorescent compounds. The degree of the enhancement was affected by basic fluorescent skeletons and by side-chains of the compounds. BSA was found to be a fairly selective fluorescence enhancement reagent for some compounds such as dansyl amino acids. BSA was applied for the determination of dansyl amino acids by postcolumn high-performance liquid chromatography with fluorescence enhancement detection. Detection limits for the amino acids were 34-169fmol on column at a signal-to-noise ratio of three. Dansyl amino acids could be measured 8-109 times more sensitively with the enhancement detection method than with the conventional fluorescence detection.

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The electrochemiluminescence of tris(2, 2′-bipyridine)ruthenium(II) [Ru(bpy)₃²⁺] was applied to high-performance liquid chromatographic determination of ascorbic acid. Ascorbic acid was separated by a C₁₈ reversed-phase column with a mobile phase containing 15mM NaH₂PO₄-K₂HPO₄ (pH 6.5). The eluted ascorbic acid was mixed with 0.5mM Ru(bpy)₃²⁺ within the flow tube. The solution then passed through a thin layer flow cell equipped with a glassy carbon electrode and both ascorbic acid and Ru(bpy)₃²⁺ were oxidized at +1.5V (vs. Ag/AgCl). The reaction of electrolytically formed Ru(bpy)₃³⁺ with oxidized ascorbic acid emitted light. The detection limit was 10pmol for ascorbic acid at an S/N ratio of 3, and the linear calibration range was 0.06-80nmol. The method was successfully applied to determination of ascorbic acid in soft drinks and apple juice.

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The effect of a mobile phase polyvalent counter ion on the retention behavior and peak intensity of sulfate in non- suppressed ion chromatography was quantitatively studied using a chromatogram simulation method. In this study, both indirect photometric detection (IPD) method and conductometric detection (CD) method were evaluated. With the IPD method, the retention of sulfate was observed to decrease in the presence of the polyvalent counter ion (Trien) without any change in peak intensity. With the CD method, however, peak intensity of sulfate decreased and, under some conditions, gave a negative peak in simulation as was also observed in actual experiments. The present work demonstrates the possibility of predicting the effect of a polyvalent counter ion on sulfate retention without resorting to physical experiments.

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The separation of four kinds of impurities contained in commercial food Yellow No. 5 was performed by using counter alternative current chromatographic (CACC) method with the solvent system composed of 2-butanol and water. These isolated impurities were identified to be RS-SA (trisodium salt of 3-hydroxy-4-[(sulfophenyl)azo]-2, 7-naphthalene sulfonic acid), GS-SA (1-(4-sulfophenylazo)-2-naphthol-6, 8-disulfonic acid), DONS (disodium salt of 6, 6′-oxybis(2- naphthalene sulfonic acid)) and 2N-SA (sodium salt of 4-[(2-hydroxy-1-naphthalenyl)azo] benzenesulfonic acid), respectively, by structural analyses. GS-SA was newly isolated from Yellow No. 5 by using the proposed CACC method.

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Several metal chelates with 2-(5-nitro-2-pyridylazo)-5-(N-propyl-N-sulfopropylamino)phenol (Nitro-PAPS) have been extracted into 1, 2-dichloroethane forming ion-pairs with the tetraphenylphosphonium ion (TPP⁺) as a counter cation. The extracted chelates were back-extracted into the aqueous phase containing dodecylbenzenesulfonate as a counter anion for TPP⁺. The metal chelates in the aqueous phase were separated and detected by reversed-phase high- performance liquid chromatography using tetrahydrofuran-acetonitrile-water (15:10:75) containing a 0.01M phosphate buffer (pH 6.0) and a 2×10^-6M Nitro-PAPS as a mobile phase. The detection limits (10σ) were 0.1ppb for copper and nickel, 0.05ppb for cobalt, and 0.4ppb for iron. The proposed method was applied to the determination of those metal ions in actual samples, such as river and rain water.

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The advantages and limitations of steam chromatography are discussed. The peculiarities of a new steam chromatography version with a polar stationary liquid phase (inorganic salt-water) were investigated. The influence of the salt nature (as a stationary-phase component), temperature of resolution and water-vapor concentration in the mobile phase on the selectivity was studied using a homologous series of n-alcohols C₁-C₈as a molecular probe. The ascertained regularities as a rule differ from those known for the traditional liquid phase in gas chromatography. The specific efficiency of a packed column with a water-salt phase (NaNO₃-water) and polydimethylsiloxane (SE-30) is similar. Examples of methanol determination in petrol and the impurities in a methanol determination are given.

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An enzymatic FIA method for the determination of gallotannin is proposed with an application to green-tea infusion. Gallic acid moieties of gallotannins are released by the action of tannase, and the increase in the free gallic acids level is estimated by a chromogenic reaction with rhodanine. The analytical results were verified by HPLC.

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Atropine selective electrodes with PVC membranes and without inner reference solutions were prepared, characterized and used in the analysis of pharmaceutical products. Their sensor system incorporates atropine-tetrakis(4-chlorophenyl) borate as an ionic exchanger and 2-nitrophenyloctylether (Type I) or dibutylphthalate (Type II) as solvent mediator. The electrodes showed stable and rapid responses (about 6s) for 1.2×10^-5-10^-1M (Type I) and 1.4×10^-4-10^-1M (Type II) atropine (ATR). A slope of about 58mV/log[ATR] was obtained in a 2.5-9.0 pH range. Both type of electrodes showed good selectivity. Their reproducibility was ±1.5mV throughout the working day. Electrodes with 2-nitrophenyloctylether as solvent mediator showed both wider linear response zone and better selectivity to sodium. Therefore they were used in direct potentiometric determinations of atropine in ophthalmic products. The results obtained showed an average recovery of 102% and a relative standard deviation of ±3%.

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Cobalt(III) oxidation was applied to an on-line pretreatment of organic phosphorus compounds in a system of flow injection analysis (FIA). An FIA manifold, comprised parts for cobalt(III) oxidation and subsequent Molybdenum Blue spectrophotometric measurement, was assembled and the analytical conditions of the system were optimized. A platinum wire (0.2mm×3m) was inserted in a pretreatment coil (1mm i.d.×5m) for accelerating the digestion of organic phosphorus compounds by cobalt(III) ions. Cobalt(III) ions could completely convert organic phosphorus (<1mg dm^-3) to phosphate ions with the aid of the platinum catalyst at room temperature and in a relatively short time (average residence time in the coil: ca. 7min). The detection limit for phosphorus by the subsequent spectrophotometry was 0.005mg dm^-3 (S/N=3) and the relative standard deviation of repeated measurements (n=10) was below 3% for 1mg dm^-3 (as P) disodium phenylphosphate. The present method reduced the amounts of the pretreatment and coloration reagents required and the time for analysis (10-12 samples could be determined per 1h), compared to the amounts and time needed for the batchwise pretreatment method.

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Collision-induced dissociation mass spectrometry/mass spectrometry (CID-MS/MS) was effective for estimating the substituent groups of porphyrin. The substituents of the porphyrin plane, which form the pathway for an oxygen- binding reaction, are essential for its oxygen-binding affinity. The CID-MS/MS of 5, 10, 15-tris(o-pivalamidophenyl) monoaminoporphyrinatocobalt and 5, 10, 15, 20-tetrakis(o-pivalamidophenyl)porphyrinatocopper was measured, and their fragmentations were studied using B/E-constant and B(1-E)^1/2/E-constant linked-scan techniques. These CID- MS/MS spectra clearly show that the substituent group represents the eliminations of the alkyl and acyl radicals from the molecular ions. Thus, the CID-MS/MS technique has been proven to be useful for characterizing porphyrin substituents.

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In order to clarify the probing depth of ultraviolet photoelectron yield spectroscopy, the escape depth (L) of photo- electrons with kinetic energy (E_k) lower than 1.5eV in hydrocarbon films was determined by using self-assembled monolayers ofn-alkylmercaptane adsorbed on gold. The yield of photoelectrons from the gold substrate decreased exponentially as the chain length of n-alkylmercaptane increased. TheLwas 1.0±0.1nm for electrons with E_k lower than 0.3eV, and increased to 3.0±0.9nm for electrons with the maximumE_k of 1.5eV.

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Rare-earth ores (monazite, ion-adsorption type and xenotime) were analyzed using a coupled analytical method, isotachophoresis-particle induced X-ray emission (ITP-PIXE). The detection limit for each minor rare-earth element in the ores was ca. 0.01 mass% of the total rare-earth elements (TREE), when 200μg of monazite was analyzed. Since yttrium was the major component in ion-adsorption type and xenotime ores, the use of a leading electrolyte containing α-hydroxyisobutyric acid and tartaric acid as complexing agents was effective for the separation of yttrium ion from lanthanide ions.

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A method for the direct determination of trace amounts of elements in tungsten matrix by inductively coupled plasma atomic emission spectroscopy is described, with emphasis on line selection and spectral interferences. Microwave assisted sample digestion method was used for the decomposition of metal samples. The spectral interference coefficients were calculated for the 270 spectral lines of 67 elements. These values were used for line selection and to calibrate concentrations of the analytes. The limits of detection of the elements for this method were determined and compared with those obtained by flame atomic absorption spectrometry and direct current carbon arc emission spectroscopy. Analytical reliability of the proposed method was estimated by analyzing spiked solutions. The results indicated that the accuracy of multi-element analysis is satisfactory.

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A selective and quantitative separation method of iron(III) from iron(II) is described. A reliable and rapid colorimetric procedure for iron(III) determination is evaluated. An accurate and sensitive atomic absorption procedure for the determination of Fe(II), Fe(III) or total iron is inferred. Iron(III) is completely and selectively separated by flotation as an iron-thiocyanate complex using an oleic acid surfactant in the 1.5-2.5 pH. N-Cyanoacylacetaldehyde hydrazone (CyAH) was successfully used as a flame buffer in eliminating the interference of foreign species in an atomic absorption
spectrometric (AAS) determination of iron. The mechanism of the releasing action is discussed. Moreover, the mechanism of flotation is suggested. Also, the procedure was applied to determine Fe(III) and Fe(II) added to natural- water samples after the selective separation of Fe(III) thiocyanate.

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The measurement of iodine in natural-water samples by inductively coupled plasma mass spectrometry (ICP-MS) is described. The limit of detection is 10pg/ml. The element is easily determined by this method without separation or preconcentration. Because iodine is highly volatile, the obtained signal is somewhat unstable. Iodine vaporization, however, can be restrained by the addition of an organic alkali (for example tetramethyl ammonium hydroxide), making it possible to obtain a stable signal. Analytical results using the conventional calibration-curve method and the standard addition method agreed well. We determined the iodine concentration of 42 natural-water samples in the northern Kanto area. The concentrations of iodine ranged from 0.65 to 35.9ng/ml.

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For electrothermal sample introduction, a tungsten boat furnace (TBF) atomizer was transformed to an organometal generator for heated quartz cell (HQC) atomic absorption spectrometry. Inorganic lead(II) was converted to butyllead species, possibly tetrabutyllead, by a thermochemical reaction with a Grignard reagent. It instantly vaporized and was then introduced into the HQC. Utilizing an exchangeable small sample cuvette placed on the TBF for the reaction was very favorable from the viewpoints of easy handling, no memory effect, and keeping stable furnace conditions. Since the analyte was vaporized at a comparatively low temperature (800°C), essentially no interference from most foreign ions was observed. The calibration graph was linear up to 0.3mg dm^-3 of lead and the limit of detection (2S/N) was 7μg dm^-3 of lead when 100mm³ of an aqueous solution was loaded on the cuvette. The relative standard deviation (0.2mg dm^-3 of lead, n=6) was 2.0%. Analytical results for some environmental samples are presented.

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Operating conditions of a particle analyzer using inductively coupled plasma mass spectrometry were investigated to optimize the analysis of individual aerosol particles for zinc in the picogram to femtogram range. The signal intensities and their fluctuations from individual particles were strongly affected by the carrier gas flow rate, radio frequency power and sampling depth. The optimum operating conditions were determined and are discussed based on the vaporization and ionization processes of particles and the ion sampling process. Under the optimum operating conditions, fluctuations of the signals from monodisperse aerosols were improved to ca. 5% of relative standard deviation under favorable conditions, and the detection limit of zinc in a particle could be lowered to ca. 3fg.

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