Palladium was removed by extraction with cyclohexanone from hydrobromic (0.30.4 N)-sulfuric (56 N) acid solution. After the organic phase was washed with sulfuric acid (1 : 50), all the aqueous phases were combined and evaporated to dryness. The residue was dissolved in hydrochloric acid after the organic matter was decomposed by a wet method. Photometric determination of copper was done on the copperneocuproine complex extracted into chloroform. The aqueous phase was used for the determination of nickel with dimethylglyoxime.
Lead, cadmium and zinc were extracted with dithizone-chloroform and determined by the squarewave polarography.
Copper was alternatively determined by the squarewave polarography.

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Determination of bromide in industrial potassium chloride or in crude hydrochloric acid by hypochlorite oxidation was accompanied with considerable variations of values obtained. Statistical studies with experimental design method on these variations revealed that they were attributable to the time of heating for oxidation, efficiency of reflux condensation, coexistence of iron, and gradual inactivation of sodium hypochlorite reagent. It was also found that the indicator added in the preliminary neutralization of the sample gave negative errors.
The author recommended that (1) the neutralization of the sample should be done without an internal indicator, (2) a large amount of Fe³⁺ should be preliminarily removed, (3) the heating for oxidation should be done with reflux condensation and continued for more than 10 min. after boiling, and (4) sodium hypochlorite reagent should be renewed before use.

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The cupric diethyldithiocarbamate (Cu-mate) method was applied to the determination of organic mercury in organomercuric pesticides. Organic mercury was preliminarily extracted with chloroform to be seperated from inorganic mercury. Cu-mate reacted with phenylmercuric acetate (PMA), phenyl mercuric chloride (PMC) and ethyl mercuric chloride(EMC) to cause a quantitative decrease of optical density at 436 mμ. As anionic iodine inhibited the reaction, phenyl mercuric iodide(PMI) could not be determined by this method. The presence of mercuric or cupric ion had no effect on the determination.
A simplified method for the determination of PMA and PMC in the technical grade preparations and dust formulations was presented. The method is useful for the routine analysis and the stability test of organomercuric pesticides.

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A direct extraction of mercury(II) into dithizone-CCl₄ solution was investigated for the purpose of determining this element in the presence of copper(II). Interference caused by copper(II) was eliminated by measuring the absorbance of extracted solution at an isobestic point which exists 480 mμ or 573 mμ in dithizone and cupric dithizonate system. A method of determination based on this principle was developed. An alternative use of interfering filters also gave a good result.

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A method for determining traces of samarium and europium in highly purified graphite applicable to the range from 0.10 to 0.90ppm and from 0.060.24ppm, respectively, was established on the basis of emission spectrographic procedure.
Standard samples were prepared with highly purified graphite, samarium oxide and europium oxide, respectively, 0.2ppm of silver chloride and 0.2ppm of auric chloride as internal standard elements for samarium and europium, respectively, and 2 percent of sodium fluoride as a spectrographic buffer substance. A d. c. arc technique was used to excite the elements. The experimental conditions for excitation were 280V, 21A, analytical gap; 5mm in argon atomsphere, and exposure time was 60 sec. and 90 sec. for samarium and europium, respectively.
The intensity ratios of Sm: 3306. 35Å/Ag: 3280.68Å, Eu: 2823.94Å/Au: 2675.95Å were found to be proportional to the samarium and europium contents and were used for the determination. The standard deviation in this method was below 14 percent.

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A method for the determination of silicon has been investigated by means of oxidimetric titration of molybdenum blue.
After an addition of 50 ml of 10% ammonium molybdate solution to the sample solution, the mixture is adjusted to pH 1.6 and 2.5 for 10 and 5mg silicon, respectively. Silicomolybdic acid formed is reduced to molybdenum blue that corresponds to the reduced state of two electrons by adding 20 ml of 10% sodium sulfite solution and boiling for 7 minutes. The excess of sulfite is decomposed by increasing the sulfuric acid concentration to 2 N and boiling for 15 minutes. The solution is titrated with 0.05 N potassium permanganate solution until the blue color disappears. The amount of silicon is calculated by the following equation:
Si (mg) =0.7022×V
where V is the ml of the potassium permanganate solution against the reagent blank.
When the pH at the formation of silicomolybdic acid is 2.4 to 2.6, 3 to 6 mg of silicon was determined with coefficients of variation of 0.5 to 2.7%.

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The separation of cations has been studied by circular chromatography with a new type dithizone-impregnated silicagel thin layer, and the results were compared with those by the paper chromatography.
The thin layer has been prepared by adding 30 ml of 0.3% dithizone-chloroform solution to 10 g of silicagel (Wakogel B-O). The cations are separated to form colored chromatograms of concentric circles of metal chelates. For the sample solution of a mixture of Hg²⁺, Cu²⁺, Cd²⁺, Ni²⁺ and Zn²⁺, the best results were obtained by the developer with either 12N acetic acid: acetone=1 : 1 or 24N acetic acid: acetone =1 : 0.66. The colored chromatograms obtained were much clearer than those by dithizone-impregnated paper chromatography.

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An analytical method of antimony in glass by the square-wave polarography has been presented in which the recommended procedure is as follows.
The powdered glass sample is decomposed with a mixture of hydrofluoric acid and oxalic acid. After driving off oxalic acid at 155°C, the residue is dissolved in 2N hydrochloric acid used as the supporting electrolyte, and square-wave polarogram is recorded from 0-0.3 V vs. Hg pool. A linear relationship exists between the wave height and the antimony concentration in the range 05×10^-5 M Sb. Effects of coexisting ions are shown in Table I.
The method is applicable for various types of glass including lead and barium glasses.
The time necessary for an analysis is about 3 hours because chemical separation of antimony is unnecessary and determination can be carried out with a small amount of sample about 100mg.

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The determination of the dissolved oxygen in water, based on the oxidation of metallic thallium by aqueous dissolved oxygen, is analytically investigated by means of a. c. polarography and Tl-104 radiometry.
Water is passed through a column (7.0 cm, φ 1.2 cm) of electro-plated thallium on silver grains (φ 34 mm) and the liberated Tl⁺ ion is determined.
In the range from 0.05 to several ppm, the dissolved amounts of Tl⁺ determined polarographically are identical to the value calculated from the reaction 4Tl+ O₂ +2H₂O→4Tl⁺ +4OH^-, in which O₂ is estimated independently by the Winkler-amperometric titration with constant voltage-polarized electrode method.
A radiometric technique using ²⁰⁴Tl is also examined for the continuous analysis of water, in which dissolved Tl⁺ ion is measured with a sandwich type G-M counter (counting efficiency 4.5%).
A complete linearity in the determination is achieved with good sensitivity and accuracy.

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Several organic peroxides used widely in the chemical industry are separated by thin layer chromatography.
Reproducibilities of R_f values of the peroxides are examined to obtain their clear separation and the R_f values are generally discussed. In the case of two-dimensional development, the effect of the first eluent remaining on the adsorbent upon the R_f val ue of the second development is remarkable.

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The photometric method for the determination of microamounts of gallium (150ppm) with Rhodamine B was studied, and the extraction method using a methylisobutylketone-benzene mixture was applied for the first time to a pure iron analysis as follows.
One tenth g. of sample is decomposed with 20 ml of hydrochloric acid (1:1) (if necessary a few drops of hydrogen peroxide is added), and is diluted with hydrochloric acid (1 : 1) to about 20 ml. After adding 2 ml of titanium trichloride solution (17%), the solution is let stand for 15 minutes at room temperature. Two ml of Rhodamine B solution (0.5%), and 1 ml of butylcellosolve solution (1 : 2) are added, and the solution is shaken. for 2 minutes with 10 ml of the mixture of benzene and methylisobutylketone (6.5 : 1). Gallium is determined by measuring the absorbance of the organic layer at 562 mμ.
Twenty μg of each element of Al, As, B, Ca, Ce, Co, Cr, Cu, Mg, Mn, Mo, Nb, Ni, P, Pb, Si, Sn, Ta, Ti, V, W, and Zn do not interfere. The time required is about 40 minutes.

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The spectrophotometric determination of trace impurities in high purity gallium was studied.
Copper and iron are determined by direct extraction using respectively batho-cuproine and bato-phenanthroline. From a citric acid solution containing gallium, copper is determined by batho-cuproine amylalcohol extraction. After copper is removed by this extraction, iron is determined by batho-phenanthroline-amylalcohol extraction.
Zinc is separated from the greater part of gallium by dithizone extraction form a citric acid solution of the sample, and stripped by dil. hydrochloric acid. Following this pre-treatment, zinc is determined by the dithizone method, in which other dithizone metals are masked.
Aluminum is determined by the oxine method after removing gallium by isopropylether and DDTC-ethylacetate extractions. As gallium reacts with oxine in a way similar to aluminum, it is important to remove gallium completely before the oxine method is carried out.
The sensitivities of these methods are 0.5 ppm copper, iron, and zinc, and 1 ppm aluminum per 2 g of sample taken.

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[in Japanese]

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[in Japanese]

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