We have determined rare earth elements(REE) in JG-1 and JB-1, standard rock samples issued by the Geological Survey of Japan, by radiochemical and instrumental neutron activation analyses. Our new data are mostly consistent with the recommended values for all the REE of JB-1 and the light and middle REE in JG-1, except for Tb. Our Tb values of JB-1 and JG-1 are about 2 times larger than the previously compiled values. For the heavy REE of JG-1, the neutron activation analysis data involving the literature values are systematically larger than the mass spectrometric isotope dilution data, with the former being as large as a factor of two for Yb and Lu compared to the latter. Incomplete decomposition of rock samples with HF and HClO₄ is suggested as a possible cause for such large discrepancies.

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Non-hygroscopic water-soluble crystals of ammonium d-10-camphorsulfonate(ACS) were prepared and proposed as a practical secondary standard substance for the calibration of circular dichroism(CD) to replace deliquescent d-10-camphorsulfonic acid(CSA). ACS gave the same CD, ORD and molar rotation, [M]_D, as CSA within an error of 1%. The molar ellipticity, [θ]_290.5+7910 (c=0.06, water) was obtained by the CSA standard solution method, by which CD and [M]_D were critically measured with a CD apparatus and a high precision polarimeter, respectively. The [M]²⁵_D+52.06 or [α]²⁵_D+20.88 (c=6, R.S.D. 0.1%) was used to check the optical purity.

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The transfer of acetylcholine ion at the polyvinyl chloride-nitrobenzene (PVC-NB) gel/water interface was studied by cyclic voltammetry, potential-step chronoamperometry and potentiometry. The results indicate that the PVC-NB gel/water interface or, in general, the interface between two immiscible electrolyte solutions can be used as the ion-selective electrode surface for both voltammetric and potentiometric analyses of ions, both based on the electrochemical principle of ion transfer at the interface.

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Determination of lead isotopes of the standard and archeological samples using ion microanalyzer has been conducted and compared with the results obtained by other mass spectrometric method. The measurement for the metallic samples, NBS SRM981 and ancient bronze coin, was made at the mass resolution of 2500, using O₂⁺ ion with net energy 12.3keV and ion current 0.3-2μA as a primary ion beam, while for other non-metallic samples a primary ion beam of O^- ion, net energy 9.8keV and ion current 40-250nA, was used to eliminate surface charging. Isotope ratios ²⁰⁴Pb/²⁰⁶Pb, ²⁰⁷Pb/²⁰⁶Pb, ²⁰⁸Pb/²⁰⁶Pb were determined with precisions 0.1-0.5%. Upon the measuring conditions examined, ten ancient glasses and glazes of faience excavated in Japan and in Iraq were analyzed. From the data obtained as well as those reported, it has been inferred that the glass sample found in Mikumo, Kyushu, was imported in Yayoi period from the north of China presumably as a Zenkankyo (Mirror of the Earlier Han), while four glass samples found in Heiankyo, Kyoto, were imported in Heian period from the south of China as Gokankyo (Mirror of the Later Han). Glazes of faience excavated in Iraq showed different lead isotope ratios from either of the glass samples excavated in Japan.

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The effect of the hydrostatic pressure, P, on the electrochemical potential, φ, of a 0.60M(=mol/l) aqueous sodium chloride solution, which can be taken as the sea water model, is investigated. The hydrostatic pressure is produced by a pumping scheme where external sample solution, Δm, is introduced into the hydrostatic pressure resist vessel. The φ value is measured in terms of the electromotive force of silver wire electrode, taking another silver wire coated with silver chloride as the reference electrode. In the solutions where oxygen is not present, the φ values do not show dependence on P throughout the range from the normal pressure to about 400atm(1atm=101325Pa), the limit of the measurement, and probably to P over 400atm, whereas, when oxygen is present, φ shows marked dependence on P for P′s below ca. 100atm, but not for P′s over the latter critical P value. It has been noticed also that Δm′s linearly increase with P in the range below 100atm, but do not increase much for P′s over the latter pressure. How this result is related with the layer structure of the sea is discussed. The results suggest that the critical pressure of 100atm refers to the structural change of water at that pressure.

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Microgram amounts of iron(III), gallium(III), thallium(III), antimony(V), and antimony(III) were collected by adsorption on activated carbon from hydrochloric acid solutions. The extent of adsorption was determined radiochemically or spectrophotometrically. The hydrochloric acid concentrations that gave the highest recoveries (_??_90%) were: 7M for gallium, 1M for thallium(III), 9M for antimony(V), and 3M for antimony(III). Thallium(I) was not adsorbed, but it was oxidized to thallium(III) by air in the presence of activated carbon. Iron(III) was adsorbed more satisfactorily from 0.1M hydrochloric acid-(6-12)M lithium chloride solutions than 6-10M hydrochloric acid solutions. Probably the metals are adsorbed as chloro-complexes. Iron and gallium in aluminum alloys were determined spectrophotometrically after adsorptive separation.

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A cation-exchange separation method has been developed for separating the rare earth elements from scandium, using hydrobromic acid as the eluent. Optimum conditions, chosen on the basis of tracer experiments, are: Dowex 50W-X8, 200-400mesh resin, 6.5-7M HBr, and a flow rate of less than 0.9cm/min. Under these conditions more than 99% of the REE are recovered in the first 12 column volumes of eluent, while leaving all the scandium on the column, and separation factors of 10²-10³ are readily attainable. This method has been used for radiochemical neutron activation analysis of meteorites, in conjunction with a procedure for determination of 19 siderophile or volatile elements. It is faster than the conventional hydroxide-fluoride precipitation, and hence permits a large number of samples to be processed simultaneously.

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A method for the simultaneous determination of selenium species such as selenium(IV), selenium(VI) and organic selenium in natural waters has been developed in this paper. Selenium(IV) was fluorometrically determined after extracting the complex of 2, 3-diaminonaphthalene (DAN) into cyclohexane. Selenium(VI) in the sample was first reduced to the quadrivalent state by adding potassium bromide in 1.3M hydrochloric acid solution, then the total inorganic selenium was determined by the same technique as the determination of selenium(IV). The amounts of selenium(VI) can be calculated by subtracting the amounts of selenium(IV) from the total inorganic selenium. Organic selenium was determined as follows: all selenium, including inorganic selenium(IV), selenium (VI), and organic selenium, was coprecipitated with tellurium(IV), and then reduced to elemental selenium and tellurium by hydrazine sulphate in acid solution (4M HCl for river water samples; 1-2M HCl for sea water samples). The elemental selenium and tellurium were dissolved in a mixture of nitric acid and hydrochloric acid, reduced to selenium(IV) by boiling with 6M hydrochloric acid, and also determined by the DAN fluorometry. The amount of organic selenium was estimated by substracting the amount of both selenium(IV) and selenium(VI) from the total amount of selenium determined by this coprecipitation method. Interesting results were obtained from applying this method to river- and sea-water samples.

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A method for the simultaneous determination of phosphate and silicate was established by high performance liquid chromatography as their molybdocomplexes. The excellent separation of them was performed on a column packed with Styragel 60 A (Waters Associates, lnc.) using an aqueous 55%(v/v) acetonitrile solution containing 0.75M sulfuric acid and 0.02M tetrabutylammonium hydrogensulfate as an eluent. The calibration curves for phosphate and silicate were linear in the range 0.03-10μgP/ml and 0.01-5.0μgSi/ml, respectively. The method was applied to the determination of phosphate and silicate in human urine and plasma.

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In selenium determination by carbon-furnace atomic absorption spectrometry, organic materials severely decrease selenium sensitivity. In order to remove the severe negative interference due to organic materials, matrix modifications by addition of Pd, Pt, Ni and Rh were compared. Palladium was found to be most effective. Addition of 100μg ml^-1 Pd completely removes the negative interference due to up to 1.5% albumin and restores the sensitivity to that of a simple inorganic Se(IV) solution without organic materials.

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An improved fully automatic controlled system for calorimetry has been employed with the aim at studying relatively weak complex formation equilibria in solutions. Complex formation reactions between zinc(II) and thiocyanate ions have been investigated in an aqueous solution containing 5mol dm^-3 NaClO₄ as a constant ionic medium at 25°C. Calorimetric titration curves obtained were well explained in terms of formation of the [Zn(NCS)_n]^(2-n)+ (n=1-4) complexes, and the formation constants and enthalpies of formation of the complexes have been determined. The stepwise enthalpy and entropy values at the second step of formation of the [Zn(NCS)₂] complex were more positive than those at other steps, which suggested that water molecules solvating the metal ion were extensively liberated at the second step.

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Electrochemical investigations of 1 -MeO-PMS(1-methoxy-5-methylphenazinium methyl sulfate) and PMS (N-methylphenazinium methyl sulfate) were performed. Both 1-MeO-PMS and PMS were very strongly adsorbed only onto the basal plane of the highly oriented pyrolytic graphite and showed a reversible voltammetric response. The amounts of the adsorbed 1-MeO-PMS and PMS on the basal plane were (2.4-3.5)×10^-10mol/cm² and (3.7-6.7)×10^-10mol/cm², respectively. NADH (nicotinamide adenine dinucleotide) is oxidized by electrodes with adsorbed 1-MeO-PMS or PMS, at-0.04V. vs. Ag/AgCl at pH 7.0. The oxidation currents are proportional to the concentration of NADH. Both 1-MeO-PMS and PMS are unstable in bulk solution at pH values above 6, but are stabilized markedly by the adsorption onto the basal plane of the graphite electrodes.

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Extraction-spectrophotometric determination of pilocarpine with copper(II) and tetrabromophenolphthalein ethyl ester(TBPE) has been developed. Pilocarpine reacts with copper(II) to form a 1:1 stable cationic complex that can be extracted with TBPE dye anion in an aqueous layer buffered at pH 9 into 1, 2-dichloroethane. Molar absorptivity of the ion associate is 1.8×10⁴mol^-1 cm^-1 dm³ at 528nm and concentrations of copper(II) and TBPE for 1×10^-5 mol dm^-3 (2.4μg cm^-3) pilocarpine are 2×10^-4mol dm^-3 and 3.2×10^-4mol dm^-3, respectively. This method can be applied to the determination of trace amounts of pilocarpine in an ophthalmic solution.

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A simple and selective method for the determination of α-keto and hydroxy acids was developed. These acids were detected spectrophotometrically by use of ferric perchlorate. Their simultaneous determination was performed by high performance liquid chromatography employing the post column derivatization method. Under our conditions, pyruvic acid, oxalacetic acid, α-ketoglutaric acid, lactic acid, tartaric acid, citric acid, malic acid, β-hydroxybutyric acid and oxalic acid were determined in the range of 2-100nmol at the sample size of 10μl. This method was also applied to the determination of pyruvic acid and lactic acid in human whole blood.

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A high performance liquid chromatographic(HPLC) determination of pyrrolidine, piperidine, and morpholine in water at μg/l level has been developed. These heterocyclic amines are converted to their 1, 2-naphthoquinone derivatives by pre-column derivatization with potassium 1, 2-naphthoquinone-4-sulfonate. The derivatives are extracted into dichloromethane, concentrated, and determined by a HPLC system equipped with a photometer set at 436nm. This proposed method is simple, sensitive, and selective for detection of trace amounts of amines in water. The calibration curves of amines were linear up to 100μg/l. The precision of the method is 0.9 to 4.7% for the analysis of water at the 10μg/l level. By this method, piperidine was detected at 0.4μg/l in an effluent of a biological wastewater treatment plant.

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