Quantitative analysis of solid sample insoluble or difficultly soluble in solvent used in infrared analysis was investigated in a dispersed phase in liquid paraffin. As an example of analysis, a mixture of 1, 5-dinitronaphthalene and 1, 8-dinitronaphthalene obtained after removal of mononitronaphthalene by extracting with carbon disulfide from nitrated naphthalene is determined by using 11.24μ and 11.96μ, respectively, as key bands and the relation between wave heights of these two key bands in the absorption spectrum and the mixed ratio of these two substances was investigated to find a few working functions adjusted in such a way as to give no effect by the difference of the thickness of sample layer, in which an estimating line obtainable by plotting the ratio of content of 1, 5-isomer/1, 8-isomer in ordinate and B/(B-A) (where A=wave height at 11.24μ, and B=wave height at 11.96μ) in abscissa is found to be linear; this working function is simple and useful. By use of this working curve, quantitative analysis of commercial products were carried out. The standard deviation of analytical data of 1, 5-isomer observed by this method, when the content is within the range of 3050%, was about ±2%.

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The Changes of the Mobility of Ion and the Length of Band on the Filter Paper with the Change of Ionic Concentration of Buffer Solution.
The effect of mobility of Ba⁺⁺, Hg⁺⁺, Fe⁺⁺⁺ and Pb⁺⁺ in filter paper (Toyo filter paper No. 3 2×50cm) saturated with HCl-CH₃COONa-NaCl buffer solution is investigated by changing the concentration of NaCl within the range of 00.5 Mol; the mobility of Ba⁺⁺ remain practically unchanged by increasing the concentration of NaCl, that of Fe⁺⁺⁺ increased, that of Pb⁺⁺ decreased, while that of Hg⁺⁺ formed a complex ion with Cl^- and increased its mobility toward the anode. The effect of changing of cationic concentrations of buffer solution to O.040.265 Mol is investigated by measuring the average length of migration band of ions which are spotted on the paper each 0.04 cc of the concentration of O.4 equivalent per liter; a linear relationship is found between the reciprocal number of the cationic concentration in buffer solution and average length of migration band, in which the positions of straight lines of Ni⁺⁺, Co⁺⁺, Ba⁺⁺, and Al⁺⁺⁺ are found in approximately the same and their average value is expressible in a straight line: y≅5/c+16, where y=average length in mm of migration band; C=cationic concentration in Mol in buffer solution. By using Ba⁺⁺ as a sample, the relation between ionic concentration of Ba⁺⁺ and average length of migration band is investigated and found that the relationship is expressible in a straight line under a definite condition; it is possible to estimate a small amount of Ba⁺⁺ from an average length of migration band.

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U⁶⁺ can be separated from U⁴⁺ as the latter gives precipitate with (NH₄)₂CO₃. Heretofore, the separation of U from Fe is carried out with the use of (NH₄)₂CO₃ or cupferron and this method is to precipitate out the Fe, but it is unsuitable to apply on sample containing large amount of Fe and small amount of U, on the other hand, reduction of Fe³⁺ to Fe²⁺ and U⁶⁺ to U⁴⁺ causes the precipitation of U with (NH₄)₂CO₃ and these are separated each other. In the gravimetric estimation of U by precipitation with the addition of NH₄OH, the formation of precipitate is not possible unless large quantities of NH₄Cl is added, while the formation of precipitate is not possible unless large quantities of NH₄Cl is added, while the formation of precipitate is possible without NH₄Cl when U⁶⁺ is previously reduced to U⁴⁺. Since U⁴⁺ is oxidizable on heating in the presence of air, its titration with KMnO₄ should be carried out below 25°C. Dissolving of U₃O₈ (or 2UO₃·UO₂) in a solution of NH₄VO₃ in H₂SO₄ in the presence of air causes the reduction of V⁵⁺ by U⁴⁺ to V⁴⁺ which is stable in the presence of air and titrable with KMnO₄ solution, therefore, volumetric estimation of U₃O₈ is possible.

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Rapid determination of manganese in iron and steel by oxidation with ammonium persulfate and titration with sodium thiosulfate is investigated. The reaction of permanganic acid and sodium thiosulf ate is proceeded in a ratio close to 8M : 5M. A standard solution close to 1/250 M Na₂S₂O₃ (1 g Na₂S₂O₃·5H₂O/l) is standardized in every 10 days against the standard ferro-manganese solution or standard steel; 0.2 g sample containing 0.32.0 mg Mn is treated according to the method of Japanese Science Development Association or JIS method, cooled below 35°C and the solution is titrated with the standard solution with good reproducibility. The end point of those with the use of nitric acid was clear in the same way as those with the use of sodium arsenite method, especially those with the use of sulfuric acid-nitric acid mixture, and those titrated at night with the use of fluorescent light gave better result. The Mn equivalency per 1 cc standard solution is not variable by the change in amount of Mn content and the titration is not influenced by the change in amount of Mn content and the titration is not influenced by the presence of 50% Ni and 0.5% Cu, also the presence of <0.25% Cr or <3% Co gave no disturbance. The standard solution of this method is nontoxic and the method of preparation is simple in comparison with the other standard solutions.

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A new volumetric determination of pyrophosphate, based on the complex formation, has been carried out. The method was found to be superior to others, and the determination was made within the permissible error in usual volumetric analysis without the use of empirical factor. Quantitative precipitation of zinc pyrophosphate was formed in the pH range 3.83.9, and the chemical reactions in this case have been also investigated potentiometrically. In order to proceed for rapid gravimetric determination of orthophosphate, a volumetric method followed by the application of versenate complex has been performed.

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Although there are numerous reports on the quantitative estimation of mercury in organic compounds, no method is found for rapid and accurate estimation of it for those containing halogen. The present method by the writers consists as follows : the sample is decomposed in a usual type combustion tube, the mercury evolved is led, through a calcium oxide layer, into a collector containing nitric acid and the solution is titrated with ammonium thiocyanate. The procedure is finished in 35 minutes for one sample and the presence of chlorine or bromine gives no disturbance in the estimation.

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A new method for the estimation of potassium xanthate was found in the course of investigation for the determination of alcohols as xanthate. The method consists in precipitating xanthate as the nickel salt, followed by titrating the combined nickel by use of E.T.A. This procedure is not subject to undesirable effects which are caused by the presence of foreign organic substances as in the case of oxidation-reduction method. The standard deviation of the present method was 0.22% against the average of 99.40%. By using the foregoing method of determination of xanthate, the stability of potassium xanthate solution was studied under varying conditions to find out a suitable procedure for eliminating the by-product, thiocarbonate, which exerted interference on the determination of xanthate.
The reaction of the formation of potassium xanthate from aqueous solution of ethyl alcohol, carbon disulfide and potassium hydroxide was investigated. It was realized that this reaction could be applied to the determination of ethyl alcohol in low concentration. The optimum concentration of ethyl alcohol is in the range of 10 to 50 mg per 5 cc, and the reproducibility is 1.6% as a standard deviation against the average of 99.8%. In order to apply this method to the determination of alcohol in alcoholic beverage, the effect of foreign organic substances which may be present together was then studied. The influence of glycocol and tartaric acid could be eliminated by increasing the concentration of alkali. The amount of glucose should be less than 10 mg per 5 cc.

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Methods of quantitative estimation of a small amount of lead in nickel metal are investigated by use of polarographic method and by colorimetric method with dithizone. The minimum limit of estimation of lead in the presence of nickel by the direct polarographic method in 1M ammonium acetate is 0.005%, and the estimation below this limit is made by polarography after concentration with hydrogen sulfide method. In dithizone method, the conditions of extraction and the effects of the presence of other elements are investigated and a rapid method of analysis which could be applied for a direct extraction of 1g sample in the presence of nickel is established. The minimum limit of quantitative estimation by colorimetric method is 0.0002%, and it required for 1 hour for metal sample or 20 minutes in case of solution. The accuracy for estimation of 3050 γ of lead can be retained within ± 3.3% error and the method is found to be suitable for industrial analysis.
Methods of quantitative estimation of a small amount of copper in nickel metal are investigated by use of polarographic method and by colorirnetric method with dithizone. The direct polarographic estimation of copper up to 0.005% in nickel can be made within 3 hours, while the estimation by use of concentration method with hydrogen sulfide required 67 hours to estimate the copper up to 0.001%. In the colorimetric method by use of dithizone, the effects of the presence of other elements in nickel in the extraction method and the conditions of extraction are investigated and a method for industrial analysis to estimate copper up to 0.0002% in metal sample within 100 minutes or within 30 minutes in case of solution is established.

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[in Japanese]

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[in Japanese]

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[in Japanese]

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[in Japanese]

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[in Japanese]

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[in Japanese]

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