In the study of gas chromatography, it has been found that, by increasing the column temperature systematically during a run, mixtures with wide boiling point ranges can be adequately separated.
The column, a spiral-wound type, was fixed on a heating plate, and its temperature was programmed electrically. The power of the heater coil was controlled by a thermistor type temperature detector that was situated on the heater plate and by an electronic circuit with a motor driven variable resistor with which the scheduled linear column temperature rise was possible.
For decreasing the base line drift caused by the temperature rise of the column, the apparatus was modified as follows:
(1) The thermal conductivity cell which was kept in a thermostat was maintained at a certain temperature higher than the maximum of the programmed temperature.
(2) The carrier gas flow of the reference side had a packed column, similar to the chromatographic one, as a restriction.
By these modifications, the base line drift was about 0.05 mV/40 min.
The analyses of city gases and light oils are described and compared with the usual method.

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An analytical method has been devised for the determination of copper and lead in electrolytic tin and high purity selenium by square wave polarography. The mother elements were expelled, and the copper and lead were then determined simultaneously in HClO₄ supporting electrolyte.
The proportionality between height of wave and concentration of copper and lead, and the effects of electrode distance, of superimposed voltage, of electrolyte temperature, of dissolved oxygen, and finally of coexistent elements were investigated; and from these results the optimum conditions were determined and the analytical method was established.
Analytical values obtained by this method using samples of relatively small quantity (15g) agreed with those obtained by the dithizone method, and the time necessary for analysis was relatively short even for an operator having no special experience.

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A simple and rapid determination of a trace of iron in caustic alkali has been made by a polarographic method. Reversibility of polarographic wave of iron in 3M caustic soda with 0.1M mannitol has been investigated. The result indicated that on each of the first and the second wave, E_d.e.log i/ (i_d-i) curve fitted in a straight line. Although the wave heights of ferrous and ferric iron were the same, they gave only a cathodic reduced wave at the same potential and gave no reversible oxidation-reduction wave.
An addition of mannitol to an aqueous solution of alkali caused the dissolving of ferric hydroxide as a complex mannitol salt. 8.95×10^-4M ferric hydroxide in 3M caustic alkali was completely dissolved by heating for 1 hour at 9095°C with mannitol at the concentration of 0.10.3M.
Quantitative determination of about 5ppm of iron can be made rapidly with the use of the first wave.

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By an application of orange yellow coloration of an aqueous solution of iron acetylacetonate, the determination of iron was made by the light absorbancy method. The iron acetylacetonate gave different colorations depending on the pH of solution, giving a pink coloration of [Fe(C₅H₇O₂)]²⁺ in acidic solution, and an orage yellow coloration of Fe(C₅H₇O₂)₃ in neutral solution. The determination of iron was made at about pH 7 with the concentration of 0.30.5% of acetylacetone and by measuring the absorbance at 440mμ. By this method, 0.510ppm of iron can be determined. The presence of large amounts of cobalt, copper, manganese, nickel and uranium has disturbing influences.

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Flavonol forms a yellow complex with uranyl ion which is soluble with difficulty in various organic solvents, but easily soluble in tri-n-butyl phosphate (TBP). The TBP solution of this complex shows an absorption spectrum which has a flat portion of maximum absorbancy at 400415 mμ. When the pH of the aqueous phase was kept between 6.0 and 7.0, and the concentration of flavonol in TBP-n-hexane (1:1) was above 8.4 × 10^-4mol/l, the maximum absorbancy was observed. Therefore, the concentration of flavonol was fixed at 1.3×10^-3mol/l (0.03%) for the determination of uranium. The calibration curve obeyed Beer's law below 12γU/ml at least. The molar extinction coefficient was 28, 700 at 410 mμ, which was about 1.6 times that of the quercetinsulfonic acid method and about 3 times that of the dibenzoylmethane method.

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The composition and the formation constant of uranyl-flavonol complex have been studied spectrophotometrically by means of McConnell's method. From the results, it was clear that two species of the complex exist, the composition of which can be represented as UO₂Fl⁺ and UO₂Fl₂. The first and second formation constants of uranyl-flavonol complex, k₁ and k₂, were observed to be 2.2₀×10¹⁰ and 9.1₇×10⁸ respectively, and therefore, the overall formation constant can be represented as 2.0×10¹⁹. The dissociation constant of flavonol was observed spectrophotometrically to be 5.6₂×10^-11.
The uranyl-flavnol complex can be extracted in TBP as UO₂Fl₂-n-TBP.

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A high frequency furnace is a good apparatus for getting high temperature in a short time. The determination of nitrogen by the cobustion method using a small high frequency furnace has been investigated. In this paper, the apparatus for this method and its operation are described.
Preliminary experiments were carried out using the same apparatus as described in the first report. It was found that it was necessary to use oxygen gas, and to extract the gases evolved by combusion as rapidly as possible, and to eliminate all of the gases except nitrogen.
The new apparatus (Fig. 2) is a modification of the vacuum fusion method. Heated copper filling was effective in eliminating oxygen, and the liquid oxygen trap condensed the water vapor and carbon dioxide completely.
Finally, the apparatus was improved with an excellent mercury diffusion pump (Fig. 4), and the nitrogen in metals was determined in about 30 minutes. This apparatus can be used for the former method as described in the first report, and to determine carbon, too.

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The determination of nitrogen in metals has been investigated with the use of apparatus described in the third report. Various kinds of fluxes were examined, and cupric oxide was found to be the best one. A sample was well mixed with cupric oxide and heated by a high frequendy furnace in oxygen gas at 50200mmHg. The sample burned and melted completely because the combustion temperature reached 15001800°C. Determinations of nitrogen in steel, titanium, ferro-alloys, and metallic silicone were carried out, and good results were obtained.
In addition, microscopic photographs were taken to observe the state of the melted sample. The limitation of this method lies in the blank value arising mainly from the crucible. This method is recommended for the rapid analysis of nitrogen in metal-containing substances such as metallic silicones and some of the ferro-alloys, because the Kjeldahl method is not suitable for such substances.

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A continuous gas absorption apparatus for a combustion method and a chelate titration method with EDTA reagent were applied to the determination of sulfur in organic compounds, and satisfactory results were obtained with errors which were allowable for microanalyses. This method is based on an application of the stability of water-soluble complex salt formed by the reaction of EDTA and PC reagent. The oxide of sulfur produced by combustion is collected as sulfuric acid, this is treated with barium chloride in excess, and the excess of barium ion is titrated with EDTA. A two-stage unit of distilled water and hydrogen peroxide is used for gas absorption. A method of continuous operation is made by devising a joint-type absorption apparatus for improvement of analytical efficiency. Satisfactory results were obtained by applying this quantitative method to the determination of various organic compounds.

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Halogenated inorganic compounds produced from thermal decomposition of a sample by the combustion method are absorbed in a continuous joint-type absorption apparatus by the utilization of oxygen and air, the halogen ions are precipitated with silver nitrate, the precipitate is dissolved by reaction with K₂Ni(CN)₄ for liberation of Ni²⁺ equivalent to the amount of silver, and this is titrated with EDTA for an indirect determination. Satisfactory results were obtained by applying this method to the determination of halogen in organic compounds. The apparatus designed for the precipitation and titration manipulation was such that these operations could be carried out with a single apparatus composed of a series of gas absorption and chemical treatments, thus preventing the errors resulting from using separate units.
This method has been investigated by using various standard samples, and it was found that the determination can be carried out with the accuracy required for microanalysis.

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A rapid photometric metod for the determination of fluoride in micas is described. After separating interfering ions, the fluorine is determined by measuring the absorbancy of ferric thiocyanate which has been faded by the fluoride ion. The procedure is more simple and more rapid than the gravimetric method of analysis for fluorine. The weight of sample needed for analysis is only a tenth of that required for the gravimetric method. The method is applicable for the solution with the concentration range of 0.11.0 mg F^- in 100 ml. The error found is 2% for 1.0 mg F^-, and 20% for 0.1 mg F^-.

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Methods are described for the separation of microgram quantities of silver by the use of mercury as a gathering agent. Electrolysis with a mercury cathode can be applied to the separation of silver from a dilute sulphuric acid solution. This method fails, however, in the presence of large amounts of copper or iron, because these metals deposit on the mercury cathode together with silver.
The present authors have found that silver is rapidly collected to mercury globules as dilute amalgam from a sulphuric acid or ammoniacal solution when the solution is stirred vigorously in a conical beaker by a magnetic stirrer. In this procedure, copper or iron in the solution does not deposit on the mercury. The dilute. amalgam thus obtained is heated in a silica boat at 350°C in a stream of nitrogen to remove mercury, and silver in the residue is determined by the photometric p-dimethylaminobenzylidenerhodanine method. Tracer experiments using ^110mAg indicated that recoveries of silver are usually over 95%.

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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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