A method for colorimetric determination of a small amount of aluminum in a large amount of metallic nickel has been studied by means of extraction with oxin-benzene solution and by eliminating its interference by addition of potassium cyanide. The optimum alkalinity and the concentration of reagent for the extraction are determined and effects of diverse ions have been reported together with the method for preventing the interference by lead. The minimum limit of quantitative estimation of aluminum is found to be 0.0001%.
A method for the flame photometric determination of a small amount of calcium in metallic nickel has beed studied. The minimum limit of estimation of calcium is found to be 0.1 p. p. m. when the spectral line of 554 mμ for calcium has been used and 40% methanol as a solvent. A large amount of nickel is removed by means of electrolysis with a mercury cathode or by use of ion exchange resin. A small amount of aluminum which causes interference by this method has been removed by extraction with oxin-benzene or by use of ion exchange resin.

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Traces of bismuth and copper present in silver were determined with the polarographic or photometric method after the removal of silver by the use of mercury cathode controlled at the potential of + 0.23 V vs. S. C. E. (in practice at -0.20 V vs. mercury sulfate electrode) in nitric acid solution composed of 0. 5 M-NH₄OAc and 0. 1 M-tartaric acid and 0. 04-10 % of bismuth was determined simultaneously with the copper. In the photometric method, bismuth up to 0.004 % was determined accurately as iodobismuthite.

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Triphenylsulfonium chloride, (C₆H₅)₃SCl, is synthesized and its polarographic behaviors have been investigated in this experiment. The reagent showed one-step reducing wave having a maximum wave at about -1.5v (vs. S. C. E. ), but it turned a two-step reducing wave by the addition of an maximum suppressor. The authors explained the mechanism of reaction at the electrode surface as fcllows:
Electrode reaction in the first wave (C₆H₅)₃SCl +2e→(C₆H₅)₂S+C₆H₅Cl
Electrode reaction at the second wave (C₆H₅)₂S +2e+2H⁺→S+2C₆H₆
The reagent is tested for precipitation reaction of several metal complex ions, among which Bi³⁺ and Hg²⁺ are especially sensitive and give a complete precipitation polarographically. Successful result is shown for amperometric titration of Bi³⁺ and Hg²⁺ and quantitative determination can be carried out within the error of ±1%

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Perchloric acid is used for oxidation of vanadium and found that perchloric acid quantitatively oxidizes the vanadium. This fact is applied for the quantitative determination of vanadium in steel and established a new analytical method. Since the presence of chromium in this method causes the distubance, it is vaporized as chromic chloride by heating with sodium chloride. A few new facts have been found in connection with this procedure and these are described herein. The procedure in this method can be carried out in 11-18 minutes, its manipulation is simple and the result showed better precision than heretofore known methods.

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Since the determination of mono-and bis-(hydroxymethyl)-urea in an initial reaction product byuse of infrared absorption spectra was difficult when hexamethylenetetramine is used as a catalyst, hexamethylenetetramine was removed by extraction with chloroform and used for quantitative determination by use of infrared absorption spectra with the standard deviation of 2%. Quantitative determination of hexamethylenetetramine in various kinds of initial reaction products is made by this method and clarified that nearly all hexamethylenetetramine remain unchanged during the initialreaction period.

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Studies on the quantitative analysis of crystalline powder mixtures have been performed by many workers owing to the advent of Geiger-Counter X-Ray diffractometer. This report dealt with the standard measurement of mixtures of KCl and NaCl, the accuracy of this method and more accurate technique to be used for analytical method suitable in practical plant operation. The following precautions were found to be necessary for increasing the accuracy of the experiment: 1). The sample must be fine enough with sufficient mixing by grinding. 2). Large slit must be used. 3). The intensity must be calculated from the area of diffraction peak, also the height must be taken as the intensity when the effects of crystallite are negligibly small. Since it is difficult to prepare sample consisting of a homogenous mixture, it is recommended to take a mean value of several measurement in practical operation. Thus, the relative error of ±11% from a single estimation of a mixture of _, KCl and NaCl (1 : 1 by weight) was decreased to ±5% by taking the average of 5 measurements.

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The fact that the pollution of waste water from paper manufacturing plant, especially that of sulfite pulp waste liquor, in natural water streams causes rapid foaming is utilized for a proposed method of rapid estimation of the polution of waters. Approximately 50cc sample water in an oxygen bottle, s shaken and the duration of time for disappearance of the risen foam is measured to make possible for semiquantitative determination to the extent of dilution of 10ppm of the waste liquor. The sensitivity for estimation is higher by using the sample water with lower temperature, also there are some differences between fresh water and sea water, but no remarkable difference is observed when the sea water is diluted to one-half. Since there is some difference in the stability of foam depending upon the kinds of waste waters, it is necessary to make previous test on the relation of duration and stability of foam for a particular water to be tested. By use of this technique, it is possible to estimate the degree of pollution by measuring the durability of foam without measuring the consumption of KMnO₄.

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Infrared absorption spectrum of large numbers of disubstituted naphthalenes mainly used for dye intermediates were measured and following results were obtained: (1). They showed the char-acteristic absorption wave length between 10.5 to 14μ, respectively. Those were 1, 2-substituent at 12.312.4μ, and 13.413.5μ; 1, 4-substituent at 11.912.1μ, and 13.113.2μ; 1, 5-substituent at 12.742.9μ; 1, 7-substituent at 11.311.5μ, around 12.1μ, and around 13.3μ; 2, 3-substituent at 11.411.5μ; 2, 6-substituent at 12.112.4μ, and 2, 7-substituent at 10.911.0μ and 11.812.0μ. (2). Naphthalene disubstitution product having substituent groups only in β-position and sulfo-group or its salt on either position showed always a strong absorption at 9.1μ.

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[in Japanese]

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