A method for the simultaneous identification of 24 accelerators and 19 antioxidants in vulcanized rubbers by one- and two-dimensional thin layer hromatogcraphy was presented. Sample was spotted on a thin layer of silica gel containing 5% calcined gypsum, and was developed with chloroform-benzene (10 : 9) in one direction and then with ethanol in the other. After drying in the air, the thin layer was treated by spraying with formalin-sulfuric acid (1 : 4) and then heated at 120°C for 1 hour. All of the above rubber chemicals, preliminarily extracted with chloroform, acetone and methanol from rubbers, were identified successfully by the R_f values and colors of spots and were distinguished from base rubbers partly extracted with the same solvent.

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Influences of methods of casting and sample preparation on X-ray fluorescent analysis of cast iron were investigated.
It was emphasized that the microstructures among the samples analyzed must be uniform. Casting in pure sandmold or in pure metal mold gave very good analytical results, although the sample cast in metal mold gave higher analytical accuracy. The accuracies represented as mean error, d, were : Si 0.023%, Mn 0.013%, P 0.001% and S 0.0006% for the sample cast in pure metal mold, and Si 0.058%, Mn 0.017%, P 0.0029% and S 0.0019% for the sample cast in sandmold.
The time required for an analysis, including that for the sample preparation, was about 5.5 minutes.

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Analytical conditions for the determination of magnesium and calcium by high frequency polarography were investigated. Magnesium gave an irregular wave in aqueous solution, but a good reducing wave in 20% methanol solution containing 0.1 M tetraethylammonium iodide. The reducing wave appeared at -1.79V toward negative or -2.06V toward positive (each vs. Hg pool), and was well-defined and reversible.
Its wave height did not vary at pH from 4 to 10. The peak potential was not influeneced by the overlapping H. F. potential, but that toward positive. alone was shifted depending upon the concentration of supporting electrolyte. The calibration lines werelinear for 2 ×10^-72×10^-5M of magnesium and calcium (in 0.1M tetraethylammonium iodide), and the variation of values in the repeated experiments did not exceed 2%. The magnesium wave was not influenced by 1020times of sodium, ammonium and barium ions. The interferences from lithium and potassium ions were removed by employing the peak height (either toward positive or toward negative) for the determination.

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A method for the spectrophotometric determination of yttrium or lanthanum in aluminum alloys using the separation of aluminum by oxine extraction has been established.
More than 0.1g of aluminum alloy is dissolved in 3N hydrochloric acid. To remove majority of aluminum and interfering metals such as nickel etc., the solution is treated with acetic acid and oxine, the pH of the solution is adjusted to 4.5 with 20% hexamethylenetetramine and 1N ammonia water, and the metal oxinates are extracted by shaking with 5% solution of oxine in chloroform.
The pH of aqueous solution is adjusted to 6.4 (or 6.6 for lanthanum), and it is treated with 1.8 ml of10% solution of acetylacetone in ethyl alcohol and 2.5ml of 0.05% methylthymol blue solution. The absorbance of the solution is measured at 610 mμ against reference blank.
Relative errors in the determinations of yttrium and lanthanum over the range from 0.05 to 7.0% are both within ±3%.

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Selective titration of calcium in the presence of magnesium with glycoletherdiaminetetraacetic acid (EGTA) was studied.
A small amount of silver ion is added before the titration to establish a reversible potential with the silver electrode.
The potential of the silver electrode is determined by [Ag⁺], and given as follows :
E=E°+0.0592 log [Ag⁺](25°C)
In this titration, the fraction titrated, a=C_Y/C_M, is related with [Ag⁺] by the following equation :
a=1-[Ag⁺]/C_Ag-[Ag⁺]·K_AgY·α(M)/K_MY+C_Ag-[Ag⁺]/[Ag⁺]·α(Y)/K_AgY·C_M
The equation expresses that the smaller the value of K_AgY· α(M)/K_MY, and α(Y)/K_AgY· C_M, the sharper is the end-point obtained.
Using this equation, the optimum conditions for titration such as pH, and concentration of the indicator ion, can be derived theoretically.
Calcium in the presence of ten fold excess of magnesium can be determined satisfactorily at pH 10.

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A spiral platinum wire electrode coated with manganese dioxide can be used as an indicator electrode for the potentiometric titration of various metal cations with EDTA or EGTA.
When a small amount of manganese ion is added before the titration, the potential of the indicator electrode at 25°C is given by the following expression:
E=E°-0.0296 log [Mn²⁺] -0.1183 pH
where the concentration is assumed to be equal to the activity.
It was shown that the electrode potential is dependent on the manganese ion concentration in the solution and its pH value.
The titration must be carried out in neutral or alkaline solutions, because stability constant of manganese-EDTA complex is not so great, and the indicator electrode attains equilibrium more rapidly in alkaline solutions than in neutral.
Chloride ion does not interfere with the MnO₂ electrode, permitting the use of an Ag-AgCl reference electrode, and the equivalence point is determined from the maximum slope of the titration curve.
In the case of titrations with EDTA, Cu, Cd, Pb, Zn and Co can be determined at pH about 7 in a succinate medium, and Cu, Cd, Zn, Co, Ca and Sr at pH about 9 in ammoniacal medium. In the case with EGTA, Ca can be selectively determined in ammoniacal medium (pH about 9) in the presence of five fold excess of Mg, which forms only a less stable complex with EGTA.

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Radioactive parent-daughter pairs, ⁹⁰Sr-⁹⁰Y and ²¹²Pb-²¹²Bi, are mutually separated and identified by thin layer electrophoresis on cut pieces, 5cm × 2 cm, of Chromatosheet (Silica gel, Toyo Filter paper Co.), using an apparatus recommended by Kohn for the acetylated cellulose electrophoresis.
The electrophoresis is carried out 5 min with 300 V/5 cm, using 0. 15M citric acid as the electrolyte. The samples are spotted at 1 cm from the cathodic end of Chromatosheet.
The merits in this procedure are : (1) separated zone, compact and clear, (2) simple procedure and readiness of collection of the separated species, (3) no cooling necessary and high reproducibility, and (4) much economical (40 pieces out of one sheet, 20 cm × 20 cm), and free from radioactive staining of the apparatus by discarding the waste pieces. The method is convenient for the separation, especially, of ²¹²Pb and ²¹²Bi, and is recommendable for graduate course students as one of their elementary practices in radiochemistry.
Thorium nitrate and barium palmitate are used as the emanating source for collecting ²¹²Pb, and optimum voltage and collecting time are decided. The identification of ⁹⁰Sr and ⁹⁰Y are done by sodium rhodizonate and auto-radiography, and that of ²¹²Pb and ²¹²Bi are by dithizone-chloroform extraction followed by the activity measurement by a 2π gas flow counter with Q gas.

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Square-wave polarographic method for the determination of indium in iron and steel was studied as follows.
Two tenths gram of sample is dissolved in hydrochloric acid and nitric acid, and the solution is evaporated to dryness. The salts are dissolved in 2 ml of hydrochloric acid (1 : 1), diluted with 10 ml of water, and, after an addition of 10 ml of hydroxylamine hydrochloride solution (10%), heated to boiling for 2 minutes. After cooling, the solution is mixed with 15 ml of hydrochloric acid and diluted to 50 ml with water. The resulting solution is analyzed for In polarographically. The potential of the peak of In is -0.60 V (vs. Hg pool).
The method permits the determination of 0.0050.2% In at an absolute error <0.005%, within 20 minutes. One milligram of As, Pb and 0.1 mg of Sn interfere, but 1 mg each of Al, B, Bi, Ce, Co, Cr, Cu, Ga, Mn, Mo, Nb, Ni, P, Sb, Se, Si, Te, Ti, V, W, Zn, and Zr do not.

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A fluorescent X-ray method was proposed for the rapid determination of aluminum, chlorine, titanium and iron in high-density polyethylene.
The calibration curves were drawn on synthetic standards prepared by mixing standard materials (aluminum oxide, sodium chloride, titanium oxide and ferric oxide) each corresponding to 5400 ppm of the inspected element into purified high-density polyethylene.
The method is five to seven times more rapid than chemical procedures, and the accuracies were, Al: σ = 112% for 50400 ppm, Cl: σ =42% for 50400 ppm, Ti: σ =182% for 3100 ppm, and Fe: σ=242% for 1100 ppm.

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The authors have perceived that nitrate ion could be reduced almost completely, close to 100%, to nitrite ion by zinc under selected conditions in the presence of appropriate salt and acid, which, in this experiment, were sodium acetate and sulfanilic acid.
To 25 ml of sample solution are added, in the order, 15.0 ml of 30% solution of sodium acetate, 0.07 g of sulfanilic acid and 0.3 g of zinc powder. After a 10 min shaking, a 10 ml aliquot of the filtrate was taken and mixed with 1.50 ml of 35% hydrochloric acid and 1.0 ml of 0.1% n-naphthylethylenediamine solution. The absorbance of the developed azo-dye was measured at 550 mμ after about 20 min. Nitrite initially present in sample was not destroyed by this procedure, and hence the values estimated were the sum of nitrate and nitrite ions. Alternatively, the nitrate ion was determined directly by heating the sample with sulfanilic acid for 10 min in a boiling water bath to destroy nitrite, and then by carrying through the procedure from the addition of sodium acetate.
A sample containing only a small amount of nitrate with a large amount of nitrite is treated conveniently by the latter procedure.
The error was±2.5% for 0.2 ppm nitrate-nitrogen, and the sensitivity represented as absorbance was 0.159 for 0.1 ppm nitrate-nitrogen.

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A successive titration with EDTA was applied to the determination of Fe(III) and Fe(IV) in barium orthoferrate.
The recommended procedure was as follows. The sample was dissolved in hydrochloric acid containing a known excess of Fe(II) ion, by passing oxygen-free carbon dioxide under gradual heating. After cooling, the solution was diluted with distilled water saturated with carbon dioxide. An aliquot of the solution, added with the buffer solution (pH 2) deaerated by carbon dioxide, was titrated for Fe(III) with EDTA using salicylic acid as an indicator. Hexamine was then added to adjust pH to 5, and methyl thymol blue as an indicator. The solution was heated to 60°C, and titrated with EDTA to determine Fe(II) remaining in the solution. The amounts of Fe(III) and Fe(IV) in the sample were readily calculated from the values of Fe(II) and Fe(III) found by the above procedure.
These values agreed well with those calculated from the weight changes measured by a thermobalance.

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A remotely operating polarograph was developed and a new polarographic method were established for the determination of uranium in waste of purex process.
The interference of dissolved organic solvent (TBP) was eliminated by adding ammonium sulfate (3.5 M) as a coagulator. Also, interfering nitrous acid was destroyed by urea.
The recommended procedure is as follows; In a polarographic cell, mix 500 μl of the sample solution and 5.0 ml of supporting electrolyte containing 3.5 M ammonium sulfate, 1M nitric acid and 0.1 M urea. After deareation with nitrogen for 15 minutes, d. c polarogram is recorded from -0.3 to -0.9 V vs. mercury anode. Uranium content is determined referring to a calibration curve.
For the synthetic waste solution containing of 9.0 × 10 ^-45 × 10^-2 M uranium, the relative standard deviation was less than 2.5 per cent. Precision data for bench top as well as for the remote procedure showed no significant difference.

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A back-titration method for the determination of (C₂H₅)₃Pb⁺ in the presence of (C₂H₅)₃Pb²⁺ and Pb²⁺ is studied. This is a modification of the back-titration method for potassium with sodium tetraphenylborate and benzalkonium chloride.
In the proposed method, (C₂H₅)₃Pb⁺solution in the presence of (C₂H₅)₃Pb²⁺and Pb²⁺is treated with excess sodium tetraphenylborate at pH45 and filtered. The excess of sodium tetraphenylborate in the filtrate is back-titrated with a standard solution of benzalkonium chloride at pH 11 using Titan Yellow as an indicator, and the amount of (C₂H₅)₃Pb⁺is calculated.
The method is successfully applied to the determination of (C₂H₅)₃Pb⁺in water from organo-lead industry.

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There is a need in the metallurgical industries for a simple, sensitive, and accurate method for determining very small amounts of sulfur. A new method suitable for such a purpose is described.
The sample in a calcined silica crucible is oxidized completely in an oxygen atmosphere within a highfrequency furnace. The oxides of sulfur are collected on silver gauze at 550°C. The oxygen is purged from the apparatus with a stream of nitrogen, and then the silver sulfate is heated in a stream of hydrogen to yield hydrogen sulfide, which is collected in an alkaline zinc acetate solution, and is subsequently determined spectrophotometrically by methylene blue method.
The method takes less than 25 minutes for a single determination with the standard deviation of 6.9 ppm on the sample containing 238 ppm of sulfur, and is reliable for the determination of as little as 1 μg of sulfur in metals.

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A rapid and simple method for the determination of small amounts of phosphine in air by detector tubes was investigated. For the rapid determination, several detector reagents showing discoloration when exposed to air containing small amounts of phosphine were studied, among which silica gel added with gold chlo ride was the most suitable. The concentration of phosphine was estimated by measuring the length of discolored zone after drawing definite volumes of air sample (100 ml, 500 ml, and 5 l) through the tube with a constant flow rate (1 ml/sec). The measurable concentration range by this method was 0.03150 ppm of phosphine. The relative error was within ±5%. Effects of water content of the detector reagent, the volume of sample, temperature of the detector tube, feeding time, etc., and influences of the other gases were tested. The method gave results generally agreeable with colorimetric analysis, and was recommended as a field method.

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The applicability of formazan compounds as the analytical reagents were examined.
A number of formazans with hydroxy-, caroxy- or arsono-radical and a heterocyclic nitrogen ring were synthesized, of which ten compounds were examined on their color reactions with metal ions as well as their solvent extraction characteristics. They were proved to be applicable as spectrophotometric reagents for trace metals and as metal indicators.

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To the determination of a trace amount of oxygen in ferrosilicon, 14 MeV neutron activation with gold as an internal standard have been employed. In order to remove the disturbance towards the count of ¹⁶N and ^197mAu with ²⁸Al, produced from ferrosilicon, experimental conditions and discriminator level of ¹⁶N were examined. To ferrosilicon powder, silicic anhydride is added step-wise and calibration curve was prepared by plotting the added oxygen amounts and S_N/S_Au. From the slope of the calibration, oxygen amount in each sample is calculated. The experiments were carried out ranging for two days with the same sample. While a great change was made on the neutron bundle when the gold internal standard method, was not employed, any influences have not been made with this method. The experimental facts indicated that the gold internal standard method was found to be effective as a practical analytical method.

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In order to obtain the sufficient precision applying the reflection-spectrophotometry for the determination of total iron contents in boiler water, the following procedure has been developed.
After the acid-digestion of sample water and the addition of ammonia water, the sample solution containing colloidal precipitates is filtered by using the Millipore membrane, followed by the desiccation under a proper condition. By this filtering procedure, diverse ions can be eliminated and iron is shown to be recovered nearly completely.
The degree of staining of the above membrane is measured by the reflection-spectrophotometric method at 320 mμ. The reproducibility of the analysis is shown to be as good as the one by the spectrophotometric methods in the concentration range of 53, 000 ppb. The proposed procedure will be applicable to the rapid monitoring of total iron contents in boiler water, especially in the case of starting or clean-up operation of boiler.

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Studies on the conditions necessary to the determination of phosphate ions mainly in polluted river water were made. After extractable substances being removed beforehand with n-butylacetate in the acidic medium of 0.7N perchloric acid (with separating funnel), phosphate ions were transformed to molybdenum blue and colorimetric measurements were carried out at a wave length of 725mμ. Almost constant values are obtained even when the solution is kept standing for several hours for the coloration after the extraction, in the region of 0.41.0 N acidity, at 532°C. Any preparation of the calibration curves are unnecessary for at least 50 days within an error of about 5%. Any influences caused by the presence of less than 100mg of urea, less than 10 mg of di- and tri-carboxylic acids and less than 2 mg of lignin have not been found. No effect was observed in the coexistence of 100mg of mono-sugar, volatile mono-carboxylic acids, formaldehyde and phenols. When this method was employed to some of the samples such as highly polluted river water in Nagoya City, Kiso River and drainage from factories, it was determined at 94108% recovery rate by the additive test of 10μg of phosphate ions.

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For the determination of gases in metals, various gas chromatographic method has widely been employed as suitable techniques. It has advantages of separating gases effectively with precision.
Present paper suggested the employment of a silicon fusion technique and of gas chromatographic analysis for the determination of nitrogen in titanium. Silicon fusion technique was shown to be recomendable desirable because (1) it is possible to make an alloy without rapid fusion if a tin foil capsule was used, when silicon and titanium were melted in graphite crucible, and then no splash of sooty substances was observed, and (2) heated alloy penetrates quickly into crucible, and transform perfectly to carbides.
The gas chromatographic method to which the concentration technique being adopted for collecting gases is found to be available for the determination of nitrogen, as a rapid and simple operation.

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