Extraction of hafnium from hydrochloric acid solution by means of tri-n-butyl phosphate (TBP) was studied as a function of the concentration of TBP, acid, hafnium, hydrogen ion or chloride ion.
Solutions containing various amounts of acid and from trace to 5.60×10^-4M of Hf with a tracer of ^175+181Hf was shaken for about 30 min. with an equal volume of TBP-benzene solution of the desired concentration. After equilibration, the intensities of γ-ray radioactivity of the aqueous and organic phases were measured for obtaining the distribution ratio of hafnium.
The extraction of Hf with 1M TBP from 7.511M hydrochloric acid solution was quantitative (log D>2) irrespective of the hafnium concentration over the range experimented. By shaking this extract again with13M hydrochloric acid solution, the hafnium was stripped quantitatively out of the organic phase into the aqueous phase.
HfO²⁺ seemed to be the predominant species in the aqueous phase in the presence of>4M hydrochloric acid, and the extractable species was supposed to be HfOCl₂(TBP)₂.

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A sensitive and rapid method for the determination of gold in ores by atomic absorption spectrometry was investigated.
A sample (?1g) was decomposed with aqua regia. Silica was removed by filtration. The filtrate was converted to about a 20ml of 1.5N HCl solution, and was shaken with 5ml of methyl isobutyl ketone (MIBK). The MIBK extract was washed successively with 7 and 3ml portions of 1.5N hydrochloric acid equilibrated with MIBK before use, and was introduced into air-acetylene flame and the absorption readings were taken at 2428Å.
The proposed method was applied to the determination of gold above 0.2ppm in ores. The results obtained for various practical samples agreed well with those by the classical fire assay method requiring a large amount sample in one analysis. The other constituents usually contained in ores did not interfere. The sensitivity and the limit of detection of this method were, respectively, 0.01μg/ml/1% and 0.01μg/ml.

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A method for the determination of S-benzyl-O-n-butyl-S-ethyl phosphorodithiolate (Conen), a new fungicide, has been presented by using thin layer chromatographic separation and colorimetry. A solution of Conen sample was spotted on a silica gel plate, developed consecutively with n-hexane-dioxane-isopropylether (80+10+5) and n-hexane-dioxane-tetrahydrofuran (80+15+5) and then eluted with methanol. The Conen in the elute was decomposed to inorganic phosphoricacid with perchloric acid and nitric acid, colored with ammonium vanadomolybdate and determined by measuring its absorbance at 420mμ. In the digestion procedure, kind and volume of eluting agents and amount of perchloric acid influenced on the analytical results. One of the satisfactory conditions was to use 20ml of methanol and 5.5ml of perchloric acid. Technical products of Conen were analysed accurately with the standard deviation of 0.45%. Ten other organophosphorus pesticides were digested quantitatively and four of them were determined accurately and reproducively after thin layer chromatographic separation.

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A method for the determination of O, O-dimethylO-(p-cyanophenyl) phosphorothioate (Cyanox) and O-ethyl-O-(p-cyanophenyl) phenylphosphonothioate (Surecide) has been developed by using thin layer chromatographic separation and ultraviolet spectrophotometry. A sample solution was spotted on a silica gel plate, developed with n-hexane-chloroform-acetone (5+1+1), eluted with methanol and hydrolyzed to liberate p-cyanophenol with the addition of sodium hydroxide solution. The content of Cyanox or Surecide was determined by measuring the absorbance of the tested solution at maximum wavelength of about 275mμ. Reliable results were obtained for technical products and several formulations of Cyanox and Surecide.

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The infrared absorption spectra of α-ferric oxyhydroxides with different aging times were studied in detail. As a result, a linear correlation was found between the frequency of variable bands of 610?643 cm^-1 and the absorbance of 890cm^-1 band of α-ferric oxyhydroxides. The correlation was further applied to the determination of the content of α-ferric oxyhydroxides in rusts and iron ores. The analytical values obtained by the present method were in good agreement with those by the thermogravimetric analysis.

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Microamounts of copper were collected completely as hydroxide precipitate by reducing with ascorbic acid and by using reducing iron (II) as a coprecipitant. The recommended analytical procedure was as follows. Less than 0.5g of a sample was dissolved in nitric acid and heated to fumes with about 3ml of perchloric acid. It was taken up with water and about 400mg of ascorbic acid and EDTA, which was slightly in excess of the equivalent to the sample taken, were added. After an addition of 70mg of Fe (II), sodium hydroxide was added to complete precipitation. The precipitate was centrifuged in a 200ml tube for 5min. with ca. 2700rpm. It was washed once with water and dissolved in 1N HCl. About 400mg of ascorbic acid was added, and the volume was made up to 25ml with 1N HCl. The polarogram was recorded over the range from-0.10V to-0.40V vs. Hg pool. The working curve was prepared by carrying through the whole procedure without an addition of EDTA on the standard series of copper solution added with about 3ml of perchloric acid. Antimony and bismuth interfered. The lower limit of determination was 0.0002%. The sensitivity of the method would be raised by increasing the amount of sample to more than 0.5g.

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A new sensitive method is described for the spectrophotometric determination of indium (III), which involves the extraction of indium-Pyrocatechol Violet (PV) chelate into 1-butanol in the presence of cetylpyridinium chloride (CPC). The chelate in the organic phase has an absorption maximum at about 600 mμ. The maximum and constant absorbance is obtained when the pH of the aqueous phase is adjusted to 6.28.0. A linear relationship is observed between the absorbance and the concentration of indium (2.5×10^-71.6×10^-6M) in the aqueous solution. The molar absorptivity of the reaction is 0.0016μg/cm².
The extracted species has the composition of 1:2:2 in the metal-ligand-amine ratio. Aluminum (III), gallium (III), iron (III), thorium (IV), zirconium (IV), tartaric acid and EDTA interfere with the determi-nation.

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The complex of copper and Sarcosine Cresol Red (SCR) was revealed to have 1:1 composition at pH 4.8.
The analytical condition for determination of Cu with SCR was as follows. To a solution containing 10120μg of Cu was added 5ml of 1×10^-3 M SCR solution, and pH was adjusted to 4.8. Absorbance at 570mμ was measured for determination. Presence of Fe (II) and Ni must be avoided. Micro amounts (0.0020.8%) of Cu in lead alloys were determined with satisfactory results.

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The effect of the flow rate of acetylene and the influence of various acids including organic acids on the determination of tin by atomic absorption spectrometry were examined, and tin was extracted into MIBK as its complexes with APDC, DDTC or dithiol which was subjected directly to the atomic absorption measurements. The sensitivity by the extraction method was three times that by the non-extractive method. Its application to the determination of tin in lead alloys gave results agreeing closely with those by the JIS method.

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After photometric titration at 562mμ of a sample solution containing cadmium and several other metals with 0.01M or 0.001M EDTA at pH about 5.0 with Xylenol Orange as an indicator, the solution was treated with potassium iodide to liberate EDTA equivalent with cadmium which was then back-titrated photometrically with a standard zinc solution. The method was simple and rapid. Mercury (II) and copper were masked with thiourea. More than 10μg of iron (III) interfered but larger amounts of sodium, magnesium, silver, lead, cobalt and zinc did not.
As little as 6μg of cadmium in the mixture of the above metal ions could be determined.

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1-Hydroxy-4-(p-nitrophenylazo)-2-naphthoic acid sodium salt (HNPAN-Na) was found to react with triethyl lead ion (Et₃Pb⁺) selectively and quantitatively, and was applied to the determination of triethyl lead. HNPAN-Et₃Pb⁺ was extracted into chloroform 1% aqueous NaCl solution (pH 8.18.3), and the absorbance at 440mμ was measured by using 1cm cell. A linear calibration line was obtained for 4.4117.6μg of Et₃Pb⁺ in 10ml of chloroform by using 2ml HNPAN-Na (10^-3M aqueous solution) with an extraction period of 1 minute. The extract was stable enough for a long time and, in the presence of ethylenediamine diorthohydroxyphenylacetic acid, inorganic lead and diethyl lead did not interfere. The lower limit of determination was 0.2ppm for triethyl lead.

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A combination of thin-layer chromatography (TLC) on silica gel impregnated with polyethyleneglycol and gas chromatography was applied to the determination of DDVP (O, O-dimethyl-O-2, 2-dichlorovinyl phosphate) in oil solutions containing DDVP alone or in combined oil preparations blended with one or more of γ-BHC, DDT, chlordane, Sumithion and diazinone.
Although the extraction rate of DDVP from the silica gel plate in TLC with acetone was 90% at most, it was raised to nearly 100% with a use of silica gel impregnated with polyethyleneglycol. An internal standard, α-bromonaphthalene was added into the acetone extract. The solution was concentrated in vacuum to a small volume, and was applied to gas chromatrography. The apparatus used was an F & M- Model 700 gas chromatograph equipped with an electrone capture detector and a 2m×3mmφ glass column packed with 4% XE-60 on 80100 mesh Chromosorb G support. The column temperature was 150160°C.
The recoveries of DDVP in the test blends containing 0.250.05% DDVP were higher than 98%, and the reproducibility was within 1.7% as a coefficient of variance.

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The analyzing crystals in fluorescent X-ray instrument were usually prepared by polishing them with cloths to give mosaic surface structure for raising the X-ray reflection intensity. The theoretical consideration {intensity formulae (1) and (2) and calculated values by their application on ADP crystal in Table 1} suggested however that by increasing the wavelengths of analytical lines the perfect crystal gave greater reflecting intensity than the mosaic crystal, and it was experimentally proved (Fig. 4). The determination of Mg by ADP crystal should be performed by using perfect crystal surface (natural surface or full etching on cut surface). The fact should be also taken into consideration in measuring fluorescent X-rays by other crystals in vacuum region.

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Methods of briquetting ferroalloy powder for fluorescent X-ray analysis were studied with special considerations on the relation of sample weight, crushing time and briquetting pressure with X-ray intensities. The analysis of variance suggested that crusing conditions were highly significant when the ferroalloys powdered under a fixed crushing condition were prepared into briquettes under pressure of 3040 tons, the X-ray intensities showed only little fluctuation and were highly reproducible. The X-ray intensities showed linear relationships with the results of chemical analysis.

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Precise methods for the rapid determination of bromide and bromate ions in their mixture have been investigated by means of short-circuit amperometric titration using a rotating (1000rpm) platinum wire electrode as an indicator and an SCE as a reference electrode.
In the case of a mixture of relatively small amount of bromide and large amount of bromate, it was titrated with silver nitrate solution to the end point of bromide in the presence of 0.1F potassium nitrate and 0.02% gelatin, and then successively titrated to the end point of bromate after reduction of bromate to bromide with sufficient amount of sulfurous acid.Excess sulfurous acid did not disturb the titration.
In the case of a mixture of relatively large amount of bromide and small amount of bromate, one aliquot of the solution was titrated similarly to the end point of bromide, and another aliquot was titrated to the end point of bromide plus bromate after reduction with sulfurous acid.
Micro amount of bromate (0.00017F) in bromide (4F) was titrated iodometrically with thiosulfate solution after oxidation of potassium iodide with bromate in an acidic solution.

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Cobalt (II) ion formed a sparingly soluble green complex with ethylxanthate in water and the complex was extracted with carbon tetrachloride. Optimum pH range for the extraction was from 6.5 to 9. The extract had two absorption maxima at the wavelengths of 284 and 356mμ (Fig. 1). The effect of xanthate ion concentration on the distribution ratio of cobalt was studied (Fig. 2), and the chemical species extracted in carbon tetrachloride was assumed to be Co(EtX)₂. Values of distribution coefficient and over-all formation constant of this complex with various ionic strengths were calculated from Fig. 5 and 6 (Table I). Under the optimum condition, the extraction of cobalt (II) ion was practically quantitatively. Beer's law was obeyed, and the molar extinction coefficient of extract at 356mμ was 1.34×10⁴.

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A quantitative method has been developed for S-benzyl-O-butyl-S-ethyl phosphorodithiolate (Conen®) in technical products and pesticide formulations by gas-liquid chromatography. Conen was separated from impurities by an apparatus equipped with a hydrogen flame ionization detector and determined by using benzylbutylphthalate as an internal standard. Most of impurities in technical Conen were identified by comparing their retention times with those of authentic samples. Conen in its formulations was determined after extraction with chloroform. Analytical results for both technical products and formulations were accurate and precise, agreeing with those by TLC-colorimetric method previously reported. The gas chromatographic condition was as follows. Apparatus: Yanagimoto GCG-550F with FID; column: glass, 1.5m in length and 3mm in inner diameter; column package: 6080 mesh, acid-washed and silane-treated Chromosorb W coated with 2% Silicone XE-60; column temperature: 180°C; carrier: nitrogen, 30ml/min.

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A highly sensitive low temperature micro DTA apparatus has been presented which is suitable for continuous measurements from -150°C to +500°C. The furnace is side-cooled and samples can be easily put in and taken out. The baseline stability is better than ±5μV at 10°C/min. in air atmosphere.
The sensitivity and the relation between peak area and sample size are examined. The temperature of the melting peak of m-xylene is constant regardless to sample size and heating rate.

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