The gas chromatography was used for determination of oxygen in cast iron. Carbon monoxide and other gases evolved from the molten sample were swept with argon from an extraction system, and were separated in each by the gas chromatography. The amount of oxygen was obtained from the amount of carbon monoxide estimated. The cast iron sample was fused with graphite tablet in a semi-sintered alumina crucible in a high frequency combustion apparatus.
The values obtained by the proposed method were compared with those by the gravimetry on the cast iron samples oxidized by heating for formation of 50400 ppm of rust. Values by both methods were linearly related. A routine precision of ±0.17 ppm was obtained on oxygen of white cast iron with concentrations as low as 5.0 ppm.

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Spectrophotometric determination of trace amounts of silica in feed water for high pressure boilers has been investigated following the extraction method developed by W. Sonnenschein.
A number of high molecular weight amines has been tested for the ability of extracting silicomolybdenum-blue from water to chloroform, and polyoxyethylene laurylamine has been found to be most adequate for the purpose.
The recommended analytical procedure is as follows. Acidic molybdate solution is added to 200 ml of sample solution. After being set aside for 15 min., 10% oxalic acid solution is added to it. After 5 min., the reductant solution, prepared just before use, containing formic acid, sodium formate, tin oxalate and sulfuric acid is added to the solution.
The solution is allowed to stand for 10 min. and is transferred to a shaking flask, to which 5 ml of 5% polyoxyethylene laurylamine solution is added. Then the solution is shaken for 3 min. with 10 ml chloroform and extraction is repeated with two successive 6 ml portions of chloroform.
The extract is collected into a 25 ml volumetric flask containing 3 ml methanol and is diluted exactly to the mark with pure chloroform. The absorbance is measured at 750 mμ in a 50 mm cell, using a reference blank on pure chloroform.
Three ppb of silica can be determined, and confidence interval extends from 2.77 ppb to 3.23 ppb at 3 ppb silica concentration in case of 95% confidence coefficient.

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In the reprocessing of irradiated uranium (Purex process) now in planning in Japan Atomic Energy Res. Inst., it becomes necessary to determine uranium extracted in TBP-kerosene, and a polarographic method has been proposed for this purpose.
Less than 1 g of the sample, TBP-kerosene solution, is weighed into a electrolytic cell, and 10.0 ml of the supporting electrolyte (mixture of 100 ml of 2N sulfuric acid, 90 ml of ethyl alcohol and 10 ml of 0.4% Tween-80 ethyl alcohol solution) is added. The solution is mixed and deaerated by passing nitrogen for about 10 minutes, and then it is subjected to polarography (-0.6-1.2 V vs. Hg).
The proposed method is simple and suitable for remote handling. Ten to 80 mg of uranium in up to 1 g of TBP-kerosene can be determined without the effects of radiation damage.

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With an object of obtaining a new organic reagent, 3-(2-hydroxyphenyl)-1H-1, 2, 4-triazole was synthesized and its reaction with various metal ions has been investigated. The reagent gave precipitate with mercury (I and II), bismuth and copper (II), while it gave a water-soluble purplered complex with iron (III).
The composition of the iron complex in aqueous solution depends on the pH, whereby the molar ratio of iron and the reagent varies between 1:1, 1: 2 and 1 : 3. By the use of this reagent, the disturbing influence of coexisting substances, except copper and mercury, was found to be very little and the determination of 0.510.0 ppm of iron was possible.

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1-Picolinoyl-2-(2'-hydroxybenzylidene) hydrazine was synthesized from picolinoyl hydrazide and salicylaldehyde, and its reaction with various metal ions has been investigated. The reagent gave soluble complexes of copper with greenyellow coloration and of iron (III) with yellowbrown.
The reaction with copper was very sensitive, and the reagent was used as a new analytical reagent for copper which afforded the determination of 0.11.3 ppm Cu. The complex had a maximum absorption at 420 mμ and the molar ratio of copper: reagent was estimated as 1:1 by a continuous variation method and a slope ratio method.

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A thick filter paper was preliminarily used with success for preparation of micro tablets (Fig. 1), but a steel disk with a central hole was found more convenient (Fig. 2, Table I). A disk holding a sample tablet was placed at the image point of Nippon Bunko Model DS-301 (or IR-S) infrared spectrophotometer, and a similar shaped disk was used as a reference.
The position of sample was regulated so that the transmittance became maximum. Gain of the recording system was raised as possible, response was reduced moderately and the spectrum was recorded with such scanning time as 2530 minutes. The obtained spectrum coincided well with that of ordinary one (Fig. 35).
Identification of 30200 μg of an unknown sample was best carried out by comparison of the spectrum with that of authentic sample obtained from a similar tablet (Fig. 7, 8). The method could be also utilized for the ability test of an apparatus (Fig. 9).

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A simple and rapid method using phenylfluorone (2, 3, 7-trihydroxy-9-phenyl-fluorone) with N, N-dimethylformamide for the determination of germanium is described. The method involves the collection of the precipitate of germanium phenylfluoronate by being adsorbed on a small amount of carbon-tetrachloride in hydrochloric acid solution, followed by the development of color in a fixed amount of dimethylformamide together with carbon tetrachloride which is the carrier of germanium phenylfluoronate.
Dimethylformamide has an ability to dissolve phenylfluorone chelate of germanium and then the use of this reagent increases the sensitivity of procedure. The absorbancy at 470 mμ is measured to calculate germanium content. Beer's. law is followed for 0.1 μg to 10 μg of Ge in 10 ml solution. Data are shown for the analyses of several lignite samples.

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The sample of high purity tellurium is dissolved in aqua regia. Arsenic and tin are separated as their bromides by distillation from perchloric acid solution, and arsenic in the distillate is reduced to As (III) from As(V) by KI and Na₂S₂O₅. It is followed by the extraction with chloroform solution of diethylammonium diethyldithiocarbamate. After the organic layer is treated with strong acids to destroy organic matters, arsenic is determined spectrophotometrically by molybdenum-blue method.
As tin remains as Sn(IV) in the aqueous layer, it is reduced to Sn(II) by thioglycolic acid and extracted with diethyldithiocarbamate-chloroform solution. The organic layer is treated with acids to decompose organic matters and tin is determined spectrophotometrically by phenylfluorone method. Micro-amounts of arsenic and tin as low as 0.5 ppm each are estimated by the proposed method.

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The fluorescence of boron chelates of o-hydroxycarbonyl compounds in glacial acetic acid-acetic anhydride mixtures, instead of the conventional concentrated sulfuric acid, has been investigated.
Relative fluorescence intensities of samples were determined by a fluorophotometer. Every 23 kinds of sample tested developed reproducible fluorescence suitable for the determination by using a mixture of 3 ml boric acid-acetic anhydride and 7 ml glacial acetic acid.
The colors of fluorescence were purple to green, while nitro compounds gave no fluorescence. The limit of detection was, as an example, 0.006 μg/ml for methyl salicylate. Ultraviolet absorption and fluorescence spectra of salicylic acid and methyl salicylate maintained the relation of mirror image indicating the absence of a vibrational frequency structure.

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1. The determination of tin: The acid concentration of the solution obtained by decomposition of a sample in nitric and hydrochloric acids is brought to 0.10.3N. The temperature is adjusted to 3050°C, and M/100 EDTA solution and thiourea are added to form tin chelate. The solution is cooled below 15°C, adjusted to pH 5±0.2 and back-titrated with M/100 zinc chloride solution using Xylenol Orange as an indicator.
2. Determination of copper: Sample solutions with and without thiourea masking copper are respectively titrated in the same way as in 1 and the amount of copper is sought from the difference in the titers of EDTA. Extensive examinations on the condition of chelate formation, effect of coexisting elements and the comparison with other methods indicate that the proposed method, can be applied for rapid determination of tin and copper in phosphor bronze. The presence of phosphorus has no influence. The analytical errors are 1% for 10 mg tin and 0.1% for 50 mg copper and the time required for an analysis is 18 min. For determination of tin in samples containing iron, lead or zinc, the former should be preliminarily separated as metastannic acid or by the methylisobutylketone extraction.

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[in Japanese]

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