A new method for the measurement of stable isotope ratios was investigated and applied to organic carbon's isotope ratio measurements in water samples. A few river water samples from Tsuchiura city were tested. After the wet oxidation of organic carbons to carbon dioxide in a sealed ampoule, the isotope ratios were determined with the gas chromatogrph-quadrupole mass spectrometer combined with a total organic carbon analyser, under the dynamic conditions. The GC-MS had been equipped with the multiple ion detector-digital integrator system. The ion intensities at m/e 44 and 45 were simultaneously measured at a switching rate of 1ms. The measurements with carbon dioxide acquired from sodium carbonate (53μg) gave the isotope ratios with the variation coefficient of 0.62%. However, the variation coefficients obtained from organic carbons in natural water samples were 2 to 3 times as high as that from sodium carbonate. This method is simple and rapid and may be applied to various fields especially in biology and medicine.

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5-Sulfo-8-quinolinol (I) reacts with magnesium, zinc, cadmium, aluminum, gallium, and indium to form the water soluble chelates with green fluorescence, and was used as a reagent for the fluorometric determination of these metal ions. The present communication reports the fluorescence properties of these metallochelates and a summary of various conditions for the fluorometric determination of these ions. The fluorescence lifetime properties of these chelates were also measured with a time-resolved spectrofluorometer. From the experimental results, the general procedure for the fluorometric determination of metal ions was established as follows; To the sample solution containing (0.120)μg of metal ions, add 1 ml of 0.045% (I) solution, and 2 ml of 20%-ammonium acetate or-ammonium chloride solution. Made up to about 20 ml with water, and adjust the pH to the optimum pH (Mg: 10, Zn: 7, Cd: 7.5, Al: 4.5, Ga: 2.5, In: 6.57), and diluted to 25 ml. Then, measure the fluorescence intensity against uranine refference standared solution (0.125μg/ml) at the ordinary temperature. By using the reagent, (0.14)μg of aluminum, magnesium and (0.520)μg of zinc, cadmium, gallium, and indium in 25 ml solution could be determined within an error of 2%. The metal to ligand ratio in the chelate which prepared under the above mentioned conditions was fluorometrically determined by continuous variation method. Although the existence of the 1 : 1 strong fluorescence chelate was observed in all metal chelates, it could not be confirmed higher chelate except the gallium-and indium-chelates. Gallium and indium are formed a fluorescent 1:3 chelate (at pH 7) and 1:2 chelate (at pH 6.57), respectively. The fluorescence lifetimes of these 1:1 chelates at the above conditions were 11.3±0.7, 10.8±0.7, 6.5±0.3, 5.0±0.3, and 4.0±0.3 ns for aluminum-, magnesium-, gallium-, cadminum-and zinc- chelates, respectively. Thus, 5-sulfo-8-quinolinolates of groups III and II metals emit the same type radiation {(490515) nm} with different lifetimes. Especially, between Alchelate and Ga-chelate at pH 4.5, there were significant difference in the lifetime by about 7 ns {(11.3±0.7) ns-(4.2±0.3) ns}. Similar result was obtained between Mg-chelate and Cd-chelate at pH 8.5 {5.8 ns: (10.8±0.3) ns-(5±0.3) ns}. By using fluorescence decay curves of these chelate mixtures, the differential kinetic analysis would be employed similar to those developed for 8-quinolinolates of group III metal by the present authours [This Journal, 25, 459 (1976)].

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This paper discusses the masking action on conductimetric titration of metal chloride with EDTA in DMF. It has been previously reported that several inflection points were observed in conductimetric titration of Lewis acids with EDTA in DMF as a result of chelating and replacement reaction. Then, it was investigated to mask and to decrease the number of inflection points by the addition of proper masking agents. Ammonium perchlorate, oxalic acid, nitric acid and lithium nitrate were used as the above masking agents. In the case of cupper(II), nikel(II) and cobalt(II) the inflection points due to replacement reaction (metal:EDTA=2:1) was disappeared by the addition of the above agents, while the other inflection point corresponding to chelating reaction (metal:EDTA=1:1) was obtained. However, magnesium and strontium chloride titration curves could not be simplified. Proper ratios of additives to metal ions were as follows; 1:1 for nitric acid or lithium nitrate and 1:2 for oxalic acid. Differential titration of mixed solution of metal chlorides which were masked or unmasked by the above agents was carried out and gave satisfatory results. Less than 10% of water gave no influence on the results.

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Aliphatic amines (dimethylamine, ethylamine, and diethylamine) and aromatic amines (aniline, N, N-dimethylaniline, diphenylamine and p-aminobenzoic acid) were titrated conductimetrically with ethylenediamine tetraacetic acid (EDTA) in dimethylsulfoxide (DMSO). EDTA was very soluble in DMSO and its solution was used as standard. A sharp inflection point were observed for the titration of aliphatic amines with EDTA at the mole ratio of 4:1. On the other hand, no inflection point was observed for aromatic amines with EDTA. The titration of aliphatic amines is possible in the presence of aromatic amines DL-serine, DL-methionine, and DL-threonine and hydrochloric acid salts of L-glutamic acid, glycine, L-cystine and L-aspartic acid were also titrated with EDTA and the observed inflection points was also 4:1. In the mixture of amino acid and aliphatic amine, the end point corresponding to the amount of aliphatic amine was observed.

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The precipitates obtained according to the conventional procedure described in textbooks were investigated by the optical microscope observation and X-ray diffraction analysis. It was found that morphology of the precipitate formed by the reaction between lead(II) and chromate ions depends on the conditions of the precipitation as follows. The monoclinic lead(II) chromate (the stable form at room temperature) was formed from a weakly acidic solution containing no or a small amount of ammonium acetate. On the other hand, fine particles of the orthorhombic lead (II) chromate (the unstable form at room temperature) were formed from a nearly neutral solution containing no or a small amount of ammonium acetate at room temperature. And fine particles of an unknown lead-chromate compound were formed from a nearly neutral and hot or warm solution containing a large amount of ammonium acetate. Both the precipitates transformed to needle crystals of the monoclinic lead(II) chromate during being left in the solution. Lead(II) sulfate was also precipitated in different shapes according to the conditions of the precipitation.

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A new and rapid spectrophotometric method for the determination of sulfite was investigated. It was found that sulfite solution has an absorption maximum at 276 nm in the presence of acid such as sulfuric, perchloric or phosphoric acid, and has a intense absorption maximum at about 285 nm or 300 nm in the presence of hydrochloric or hydrobromic acid respectively. The absorbance was greater with hydrobromic acid than with hydrochloric acid. Recommended procedure is as follows. In 25 ml volumetric flask, the sample solution and 10 ml of 7.5N hydrobromic acid were added and diluted to 25 ml with water. The absorbance of the solution was measured at the wavelength of 300 nm with 10 mm cell against water. By this method, the sulfite in the range from 0.2×10^-4 M to 4×10^-4 M {(32640)μg/25 ml as sulfur dioxide} was accurately determined. The variation coefficient was 0.5% at the sulfite level of 2×10^-4 M. Fe(III), Hg(II), Pb(II), NO₂^- and VO₃^- interfered with the determination of sulfite.

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Metals react with various complexing reagents to form water-insoluble colored complexes, which are quantitatively extracted into molten naphthalene at a temperature above 81°C. The solidified mixture of metal complexes and naphthalene is separated from the aqueous solution, dried on the filter paper, and then dissolved in dimethylformamide by shaking. The trace amounts of metals in the solution are determined spectrophotometrically. The other factors such as wavelength, pH, amounts of complexing reagents and naphthalene, shaking time, and stability are studied and the molar absorptivities, sensitivities and relative standard deviations are evaluated. The extracted complexes are stable in naphthalene and naphthalene-dimethylformamide solution. This method is characterized by the facts that the equilibrium distribution in the two phases is attained rapidly and that the complexes are dissolved by contact with molten naphthalene or by slightly shaking. The mixtures of metal complexes and naphthalene are soluble in dimethylformamide which is miscible with water. Various metals were determined by using different complexing reagents as follows: Cu, Bi and Ni with DDTC, Cu, Bi and Co with APDC, Cu, Zn and Ni with 2-methyloxine, Cu with 5, 7-dichlorooxine and 5, 7-dibromooxine, Cu with α-benzoinoxime, Fe(III) and V(V) with N-benzoyl-phenylhydroxylamine and Ni with salicylaldoxime. Copper, zinc, magnesium, cadmium and cobalt were successfully determined by using oxine as the complexing reagent and by atomic absorption spectrophotometry.

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Oxygen in lead, bismuth and their compounds and in alloys of lead was determined by carrier gas methods. Oxygen in some lead and bismuth compounds could not be determined by the usual method for organic compounds. However, oxygen in lead and in its compounds was determined accurately by a carrier gas method using naphthalene as reaction agent. A carrier gas method adding carbon as solid reaction agent was applied to lead compounds, bismuth and bismuth compounds, and favorable results could be obtained. Oxygen in alloys of lead, such as Kelmet alloy and soft solder, could be accurately determined by a carrier gas method with naphthalene and by one using hydrogen as reaction gas, respectively. One analysis took about 40 min by a gravimetric method and about 20 min by a coulometric method.

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Liquid chromatographic separation was investigated by adsorption chromatography of hardly separable stereoisomers such as 5:6-oxido-cholesteryl benzoates, 5:10-oxido-19-nor-androstane-3α, 17β-diols and their 3, 5-dinitrobenzoates, dexamethasone 21-acetate and betamethasone 21-acetate, and 5-cyano-19-nor-testosterons and their 3, 5-dinitrobenzoates, and syn-, anti-geometrical isomers such as Δ5-3β-hydroxy-androstane-17-one oxime benzoates. Prior to liquid chromatogrphy with silica gel columns, silica gel thin-layer chromatography was performed to obtain suitable liquid chromatographic systems for separation of these compounds. Seven solvent systems for thin-layer chromatography failed to effect satisfactory separation in liquid chromatography when used in the same solvent ratios. As retention times (t_R) and capacity factors (k') of these isomers were small, the separation factors (α) were insufficient for good separation. In order to effect the sharp separation in liquid chromatography, it was necessary to decrease the solvent strength in the same binary solvent mixture as was used for thin-layer chromatography, for instance from the ratio 4:1 to 1:1 in chloroform-n-hexane systems for the separation of 5:6-oxido-cholesteryl benzoates. Discrepancy in solvent strength for efficient separation between thin-layer chromatography and liquid chromatography might be attributed to the following fact that in liquid chromatography the solvent elution powder acts as an isocratic manner while in thin-layer chromatography it acts as a gradient manner.

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The evaporated thin films of mixed crystals containing pure anthracene and pure phenanthrene in pure carbazole were prepared in various mole concentration. By measuring fluorescence spectra, fluorescence lifetimes and time resolved fluorescence spectra of these samples, the determination limit of anthracene and phenanthrene in carbazole was quantitatively investigated. The concentration of anthracene in the carbazole could be quantitatively measured to 10^-7 mol/mol by the fluorescence spectra, to less than 10^-8 mol/mol by time resolved fluorescence spectra. However, it was difficult to measure the concentration of anthracene in the carbazole by the fluorescence lifetimes, for the lifetimes of the two were too near. The concentration of phenanthrene in the carbazole could be quantitatively measured to less than 10^-4 mol/mol by the fluorescence spectra, to 10^-7 mol/mol by the fluorescence lifetimes, and to 10^-6 mol/mol by the time resolved fluorescence spectra.

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In the determination of metal ions with a flow coulometric detector in liquid chromatography, mercuric complexes of diethylenetriaminepentaacetate (DTPA) or ethylenediaminetetraacetate (EDTA) have been used as a reactant because the detection is little interfered by dissolved oxygen in the sample solution and in eluent. From the view point of pollution, the use of mercury compounds is undesirable and cupric compound is more likely. Cu-DTPA was more stable than mercuric complexes as an electroanalytical reagent. However, the detection limit by Cu-DTPA was less than that of Hg(II)-complex. The variation of current efficiency of the electrochemical reaction for 20 days was 2.2%. Cu-DTPA complex with a satisfactory quality for the analysis was prepared by mixing CuSO₄-5H₂O (>99.5%) and DTPA (reagent grade). In the Cu-DTPA solution the amount of Cu should be between 100 and 101% (mol) of DTPA. The effect of electrolytic cell temperature on the optimum detection was examined and the temperatures above 20°C were suitable for the detection. The electrolytic efficiencies for Cu²⁺, Zn²⁺, Ni²⁺, Pb²⁺, Co²⁺ and Cd²⁺, separated with ion-exchange chromatography were measured. The efficiency for these ions except Ni²⁺ was almost 100% with Cu-DTPA. On the other hand, Cu-EDTA available commercially was poor reactant and the current efficiency was only (3080) %.

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A rapid and simple method for the determination of anthracene in sediment and soil was developed by using a gas chromatograph equipped with an electron capture detector (GC-ECD). The method was based upon the findings that anthracene and phenanthrene were different in the response to ECD and the stability to sulfuric acid. The procedure is as follows. The sample soil is mixed with potassium hydroxide-ethanol solution and digested under reflux for 3 hours. After cooling to room temperature, the digestion mixture is extracted by n-hexane. Interfering substances are eliminated by Florisil column chromatography. The 1st n-hexane eluate is discarded, and anthracene (plus phenanthrene) is eluted with n-hexane-ethylether (95: 5). Then the eluate is concentrated, and determined for anthracene (plus phenanthrene) by GC-ECD. After elimination of anthracene by shaking the fraction with sulfric acid, the solution is determined for background level by GC-ECD. Anthracene is calculated by subtracting the latter value from the former. Recovery of anthracene from sediment and soil was more than 91%. The detection limit for anthracene was 5ng/g. Mineral soils, volcanic ash soils and marine sediments were analyzed, and anthracene were found in a range from not detectable to 81 ng/g.

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Sodium ion selective glass electrode has been employed as an end-point detector in the automatic microtitration of cyanide ion with silver ion. An aliquot volume of 0.005M potassium cyanide standard solution containing 0.01M potassium hydroxide was accurately pipetted into a 50ml beaker. The pH of the solution was adjusted to 10.5 by adding 5ml of potassium carbonate-potassium bicarbonate buffer and was finally made up to 50 ml with distilled water. Automatic titration was then carried out with 0.005M silver nitrate standard solution at a delivery speed of 0.5 ml/min by using a sodium ion selective glass electrode (Corning NAS 11-18) and a double-junction SCE. Two potential jumps were observed for the formation of dicyanosilver complex and of silver cyanide precipitate. The first potential jump was much smaller than the second one but it was sharp and was easilly resognized on the recorder chart so that this inflection point can be used as an end point. The cyanide standard solution is stable for a few days in a polyethylene bottle. However, when the sample solution was delivered into a 100 ml beaker, cyanide ion was decomposed in air at a rate of 1% of the initial concentration during 10 min. In a 50 ml beaker, on the other hand, the stability was improved because the exposed area of the solution to air was reduced. The reproducible end-point was then obtained when the titration was carried out within 10 min. The statistic study of the reproducibility yielded 8(μl) as the standard deviation against 2.500 ml of the titrant.

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Chemical procedures were studied for high recovery and reproducible separation of selenium in post-irradiation chemistry in neutron activation analysis. Distillation followed by solvent extraction was used for separation of selenium in this paper. Distillation of selenium from HCl-HBr solution containing 30 ml each of 12N HCl and 8.6N HBr in 110 ml, which enables selenium to be distilled off as volatile halides, was employed for elimination of materials that interfere solvent extraction and of almost all interfering radioactive nuclides except those of Hg, Sb, etc. produced by thermal neutron irradiation. Recovery of selenium in this distillation was (99.6±0.3)%. Selenium was then extracted with benzene from aqueous phase(12N HCl 15ml, 60% HClO₄ 15ml), mainly as bromide, and back extracted with dilute aqueous ammonia. Complete separation of selenium was accomplished by this procedure. Nitric acid in aqueous phase lowered the extraction efficiency, but 97% of efficiency was attained if it was below 0.3%. Gross recovery of (97.2±1.2)% was found by radioactive tracer technique. This method was applied to determination of selenium in Standard Reference Materials, Bovine Liver and W-1, and the values (1.20±1.2)ppm and 0.16ppm were obtained, respectively, while their published values were (1.1±0.1)ppm for Bovine Liver and 0.11 ppm for W-1. This method of separation can be applied to neutron activation analysis of selenium in various environmental samples.

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Fusarenon-X and T-2 toxin easily gave a colored product by the reaction with the reagents used for detection of formaldehyde such as chromotropic acid, J acid and phenyl J acid, and also gave a fluorescent product with J acid in sulfuric acid. The color reaction of fusarenon-X with chromotropic acid, which is most widely used as the reagent for formaldehyde, was studied in order to establish a simple and rapid micro-determining method for trichothecene mycotoxins. The following standard procedure was chosen as the result of the discussion on various conditions: To a 20μl of sample ethanol solution in a micro-test tube(1.5 ml) with ground stopper, 1.0 ml of 1% (w/v) chromotropic sulfuric acid (91 v/v%) is added and the mixture is heated in a boilling water bath for 10 minutes. After cooling, the absorbance of the reaction mixture is measured at 583 nm using a microcell (light pas slengths: 10mm). The colored product was stable for few hours at room temperature. By the proposed method, fusarenon-X and T-2 toxin could be determined for (120)μg/20μl and (130)μg/20μl, respectively. For the other trichothecene mycotoxins, neosolaniol, nivalenol, tetraacetylnivalenol and HT-2 toxin were positive but trichothecin and dihydronivalenol were negative in this reaction.

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Atomic absorption spectrometry in aqueous phase has been tried with 0.03M K₂SO₄ and 1% H₂SO₄ solutions of Mn²⁺, Fe²⁺, Co²⁺, Ni²⁺, Cu²⁺, Zn²⁺, Cd²⁺, Hg²⁺, Hg₂²⁺, Tl⁺, Ag⁺ and Pb²⁺. As means of atomization, electrolysis and chemical reduction were employed. In the case of electrolytic reduction, the spectral change was examined in situ using platinum minigrids as optically transparent electrodes or the platinum plate which was set parallel to the incident light beam. A spectrum with an intensive peak at 238nm was observed when the Hg²⁺ solution was electrolyzed. This absorption peak did not decrease even if the applied potential was cut off, and is identified as the spectrum of Hg₂²⁺ ions which was formed by: Hg²⁺+e=1/2Hg₂²⁺ and/or Hg²⁺+Hg⁰=Hg₂²⁺. The peak at 231 nm was also obtained with Cd²⁺ solution by electrolysis, which may be ascribed to Cd⁺. Furthermore, Tl⁺, Ag⁺ and Cu²⁺ gave broad absorption peaks at 240, (245, 310), and 277 nm, respectively. On the contrary, Mn²⁺, Co²⁺, Ni²⁺, Zn²⁺ and Pb²⁺ gave no significant change in spectra although the applied potential went up to -2.5 V. The absorption peak at 207 nm obtained by electrolysis of Zn(II) solution, which is reported by Tyson and West, was found to be identical to that of Zn(II) in excess NaOH, suggesting that this is due to the Zn(II)-hydroxo complex rather than Zn(0) species. A new doublet spectrum which has peaks at 251 and 257 nm was found immediately after adding reducing reagent, SnCl₂, to Hg₂²⁺ or Hg²⁺ solution. This absorption decayed in 3min, and was not ascribed to SnCl₂, SnCl₄, or H₂SO₄ in aqueous solution. Therefore, it appears that the observed spectrum is responsible for the "atomic absorption" of hydrated mercury.

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