A method is described for the spectrophotometric determination of rhodium. Rhodium (III) reacts with an excess of Xylenol Orange (XO) to form a red chelate having an absorption maximum at 520 mμ, while a blue chelate with its absorption maximum at 598 mμ is formed when an excess of rhodium is present. The former, which was used to the spectrophotometric determination of rhodium, gives the maximum absorbance in the pH range from 2.7 to 3.3. Beer's law is obeyed up to about 60 μg of rhodium in 25 ml. The sensitivity of the reaction is 0.0052 μg Rh per cm². Among the anions tested, chelating agents such as NTA and EDTA interfere seriously with the determination. The effect of addition of some inorganic acids, on the absorbance of the colored solution, is also examined.
The presence of 1 : 1 chelate is confirmed by the method of Frank and Oswalt. The apparent formation constant of the chelate is calculated to be 2.8 × 10³ at pH 2.50.

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The complex formations of β-mercaptohydrocinnamic acid and β-mercaptocinnamic acid with nickel and cobalt ions were studied, and their applicabilities as new reagents for the spectrophotometric determination of nickel and cobalt ions were investigated.
β-Mercaptohydrocinnamic acid formed Water-soluble complexes with nickel and cobalt ions in alkaline medium. The absorption maxima were observed at 520 mμ in the nickel complex and 560 mμ in the cobalt complex. The applicability of Beer's law was confirmed at the wavelengths of the absorption maxima of the complexes when the concentration of the metal ion was less than 100 ppm. β-Mercaptocinnamic acid formed also water-soluble complexes with nickel and cobalt ions in alkaline medium. The absorption maxima were observed at 495 mμ in the nickel complex and 635 mμ in the cobalt complex. Simultaneous determination of nickel and cobalt ions in their mixture was possible by the measurement of the absorbance at 495 mμ and 635 mμ. The molar ratios of the metal ions to the ligand in solution were found to be 1 : 2 and 1 : 3 in the nickel complex and cobalt complex, respectively, by mole ratio method and continuous variation method. As these reagents were very stable, they were considered to be useful as the analytical reagents.

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β-Mercaptoacrylic acid and β-mercaptocrotonic acid were synthesized through thiuronium salt obtained by addition of thiourea to propiolic acid or tetrolic acid. Although both compounds exhibit sensitive color with various metal ions, they are not suitable as practical reagents on account of their instability in air and pungent odor. Instead of using these mercapto acids, the applicabilities of their thiuronium salts as the analytical reagents were investigated. The thiuronium salts were found to be readily hydrolyzed by alkali to produce quantitatively the mercapto acids. Simultaneous determination of nickel and cobalt ions using the thiuronium salts were possible by the measurement of the absorbances at the wavelength of absorption maximum of each complex, namely, 505 mμ for nickel and 640 mμ for cobalt. The compositions of nickel and cobalt complexes were 1 : 2 and 1 : 3 in molar ratio of metal to reagent, respectively. Thiuronium salt is very stable, prepared easily, and can be used conveniently as the analytical reagent.

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A sensitive spectrographic technique using a specially designed cup-electrode is proposed for the determination of silicon and zinc in the solution of indium arsenide. The electrode consists of an alumina cup which serves as a reservoir for the sample solution and a central tungsten-rod supporting a graphite rod, and it allows the excitation under low-voltage over damped discharge. The method is especially useful for analysis of small quantities of material. The use of hydrochloric acid has been found to improve the limits of detection. Several recommendations have been made regarding optimum conditions for the cup-elecrtode techniques. Determination-limits for silicon and zinc are 0.6 and 1.0 μg/ml, respectively, and the coefficient of variation for the determinations is within 6%. The distribution coefficients of silicon and zinc in indium arsenide crystals have been determined by applying the present method.

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For the identification of gas chromatographic eluents, pyrolysis gas chromatography has been studied.
At this first stage, individual alkylbenzene was put into the pyrolysis tube (stainless steel, 4.8 mm i. d. × 83 mm, filled with 0.77 ml alumina) followed by a separation column, and, after the examination of the experimental conditions including pyrolysis temperature, carrier gas flow rate, etc., the pyrograms of C₆C₁₀ alkylbenzenes were obtained. It was made clear that the carbon-carbon bond dissociation energy of the side chain of alkylbenzene had an intimate correlation with pyrolysis products, and that the higher the molecular weight was, the larger the decomposition which followed.

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The extraction of molybdenum (VI) -Alizarin Red S complex with quaternary ammonium chloride has been investigated for the determination of molybdenum (VI). The complex extracted into 1, 2-dichloroethane has an absorption maximum at 525 mμ, with a constant absorbance in the pH range from 4.5 to 5.5. The molar ratio of molybdenum (VI) to Alizarin Red S in the complex is estimated to be 1 to 2 for aqueous phase, and 1 to 3 for organic phase. By extracting the complex into organic phase with tetradecyl-dimethylbenzyl ammonium chloride, the sensitivity increases about three times as much as that of aqueous phase. For the absorbance of complex in analytical condition, Beer's law is obeyed at least up to 2.5 × 10^-5M molybdenum (VI) in 1, 2-dichloroethane. The effect of diverse ions is also examined.

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An oxygen bomb method has been used for both the calorimetry and the decomposition procedure for chemical analyses of organic matters. As a fundamental study for applying the method to chemical analyses, gases and aqueous solutions after combustion of polyethylene in the bomb were analyzed by mass spectrometry and ultraviolet spectrophotometry. One gram of the sample was wrapped up in a sheat of rice paper, and fastened with cotton thread passing through the platinum coil between the electrodes.
The results obtained were as follows :
(1) Experimental values of compositions of gases both before and after the combustion were in fairly good agreement with the theoretically calculated values.
(2) Average amounts of nitric acid and nitrous acid in the bomb after every combustion were 80 and 3 mg. respectively. The amounts of these acids were prominently decreased by evacuating the bomb before filling up oxygen.
(3) These nitrogenous acids are predominantly derived from the nitrogen in the atmospheric air initially present in the bomb, rather than that contained in the oxygen supplied.
(4) In either case with or without evacuation of the air in the bomb, the conversion ratio of nitrogen to the acids was about 5 mole percent, and the mole percentage of nitrous acid in the mixed acids was between 4 and 5.

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Fluorescence due to the reactions between tetracyline and metal ions, such as Th⁴⁺, Al³⁺, Be²⁺, Zn²⁺, Mg²⁺ Cd²⁺, Ca²⁺, Sr²⁺, and Ba²⁺ was investigated, and Al³⁺ was found the most suitable for the determination of tetracycline.
A fluorometric procedure is recommeneded as follows. To a 5 ml of sample solution of tetracycline hydrochloride and each of series of standard solution (0.11.0 μg tetracycline hydrochloride per ml) was added 5 ml of the aluminum reagent freshly prepared by mixing one part of 30 vol% methylcelloslolve, one part of 0.01M ammonium alum solution, and nine parts of biphthalate buffer solution (pH 5.7). After standing for 25 min., fluorescence at 510 mμ by the excitation light of 415 mμ was measured. The readings of fluorescence intensity were referred to the solution of 0.1 μg uranine per ml, because the fluorescence intensity of the standard solution made of tetracyline-Al complex varied after a prolonged exposure to the fluorometer light source. As little as, 0.11.0 μg of tetracycline hydrochloride per ml can be determined by the proposed method.

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2-Pyridinealdehyde-2'-hydroxy-5'-phenylanil has been employed for the determination of Cu (II) as its chelating reaction is selective and sensitive. The chelate is reddish-orange and soluble in water.
It was formed by adding alcoholic solution of the reagent 2 times as much as Cu (II) in weight to the sample solution adjusted to pH 3.5. After allowing the mixture to stand for 30 min. 1hr. at room temperature, the absorbance of the solution was measured at 480 mμ.
From 0.25 mg/l to 4.00 mg/l of Cu (II) could be determined directly by the above procedure.

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The relations between the vaporized amounts, vaporization behavior and spectral line intensity of gadolinium in graphite powder, and d. c. are discharge conditions have been examined with graphite electrodes.<BE>Standard samples were prepared with highly purified graphite powder, 1000 ppm of gadolinium as gadolinium oxide and various concentration of lithium fluoride as a spectrographic buffer substance. A d. c. arc technique was used for exciting the element, and the neutron activation analysis technique was used for measuring the concentration of gadolinium in graphite powder after arc discharge.
It was clarified that the vaporized amounts and vaporization behavior depended mostly on the electrode temperature. As an arc current increased, the vaporized amounts increased and the temperature. of anode was raised. Under the experimental conditions including d. c. 9.9 A-12.5 V, exposure time 60 sec, electrode gap 3 mm, and 2.0% of lithium fluoride in argon atmosphere, the vaporized amounts from mg sample were 3×10^-7 g at anode crater and 2×10^-7 g at cathode crater.
The emission line intensity of gadolinium depended on the vaporized amounts of gadolinium in argon. atmosphere. Under the experimental conditions including d. c.9.810A-12.012.5V, exposure time 60 sec, electrode gap 3 mm, and concentration of lithium fluoride from 0.5 to 10% the observed temperature range of the arc column was 28003600°K, and its correlation with the concentration of lithium fluoride was not linear. The arc column temperature was calculated by the equation ; log (Iλ/Ag) =-5040E/ T+C.

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Synergistic effect of isoquinoline (B) on the extraction of nickel with 2-thenoyltrifluoroacetone (TTA) was found to be attributable to the formation of an adduct, Ni(TTA)₂(B)₂. Using the extractability of this adduct into organic phase, a spectrophotometric method for determination of trace amount of nickel (II) was established. The pH of a smaple solution containing up to 70 μg of Ni was adjusted to about 7. After the addition of isoquinoline and TTA benzene solution, nickel was extracted into the organic phase and the absorbance was measured at 390 mμ. The sensitivity of this method was 0.026 μg/cm².
Although a preliminary separation of Cu (II), Co (II), Mn (II) was needed, each 500 μg of Fe (III), Cr (III), Th (IV) did not interfere.

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A method was proposed for the electron-capture gas chromatographic determination of methyl parathion in rice grains. To 25 g of rice grains was added 50 ml of n-hexane. After allowing to stand at room temperature overnight, n-hexane was filtered through a glass filter (17G3), and the residue was washed several times with each 30 ml of ether. The eluate was evaporated to 10 ml, and cleaned up by the alumina column chromatography using n-hexane-ether (9 : 1) as developing solvent. An aliquot of the n-hexane solution was injected into a gas chromatograph with a spiral galss column, 5 feet × 1/8 inch (outside diameter), packed with 10% high vacuum silicone grease on 4060 mesh chromosorb W and an electron-capture detector. The column temperature was adjusted at 180°C. Nitrogen was used as a carrier gas, the flow rate being maintained to 20 ml per minute. Seventy to 101% of methyl parathion was recovered by this method from rice grains containing 0.1 to 10 ppm of the methyl parathion and Sumithion.

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In the fluorescent X-ray determination of chloride in titanium sponge, the particle size of sample was brought to pass through 50 mesh sieve with special care not to alter content of impurities. It was press-molded under rigidly controlled conditions, and chloride was determined on the fluorescent X-ray intensity of Cl-Kα line by the calibration method. Although it is generally said that the favorable particle size of sample is 200 mesh or less, the authors found that, in case of titanium sponge, 50 mesh under was a satisfactory fineness for obtaining sufficient accuracy and reproducibility. The determination of chloride in titanium sponge containing 0.07% chloride gave a standard. deviation of 0.0021%. An analysis required about 20 minutes including time for the sample preparation.

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In the direct-reading spectrometric determination of molybdenum, analytical results are often interfered from the overlapping spectral lines of nickel and manganese.
In this paper, new analytical lines of molybdenum, Mo II 2038.46 Å and Mo II 2020.32 Å, were proposed in the wavelength range of 2200 Å to 1780 Å. The line Fe II 1761.38 Å was used as an internal standard. Using these spectral lines, interfering elements, excitation conditions, and reproducibility of the results were investigated.
The best results were obtained under the excitation by a spark of the critically damped discharge of a low voltage condensor. Mo II 2038.46 Å is slightly interfered from the overlapping line of manganese. With Mo II 2020.32 Å, which had no interfering element, however, 0.20% and 1.09% of molybdenum in low alloy steels were determined with the variation coefficients of 2.2% and 1.6%, respectively.

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Infrared absorption spectroscopy was applied to the determination of five brominated salicylanilides (3, 5, 4'-tri; 5, 4'-di; 5-mono; 3, 5, 2', 4'-tetra; 3, 5-di bromo salicylanilides) in their mixture. Nine wavelengths (10.87, 10.97, 11.11, 12.10, 12.82, 13.15, 13.32, 13.62 and 13.70 μ) were selected as key bands from the absorption spectrum of brominated salicylanilide solution in dimethyl formamide, and Beer's law was confirmed to be valid at these wavelengths. Nine equations of linear combination with absorbance and the amount of each component were derived from the absorbances of standard and sample solutions at these wavelengths, and the percent contents of the five brominated salicylanilides were calculated, respectively by the least square method using an electronic computer NEAC 2206.
Influences of the cell length and the concentrations of sample and standard solutions were negligible, and the absorbance of the standard could be fixed constant. Satisfactory reproducibility, precision and rapidity were obtained.

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A small amount of chloranilic acid is well extracted into nitrobenzene in the presence of tris (1, 10-phenanthroline) iron (II) chelate, and the color intensity of the organic phase (516 mμ) is proportional to the amount of the chloranilic acid anions. The maximum extraction is obtained when the metal chelate concentration is 5 × 10^-5 M in the aqueous solution buffered at pH 1.2 to 3.0. Beer's law is followed over the concentration range of 4 × 10^-64 × 10^-5 M of chloranilic acid. This extraction method of chloranilic acid is applied to the indirect spectrophotometric determination of sulfate using barium chloranilate, and the amount of sulfate up to 370 μg can be determined. Sulfate ion in water sample was determined by the proposed method with satisfactory result. The sensitivity of the proposed method for sulfate was 13 times higher than that of the ordinary barium chloranilate method.

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Conditions for dehydration of HIO₃ and formation of HIO₃, HI₃O₈ and I₂O₅ were examined through TGA, DTA and X-ray analysis. HIO₃ showed two dehydration processes at 90140°C (HIO₃→HI₃O₈) and 200230°C (HI₃O₈→I₂O₅), and the quantitative ratio of the dehydration was found to be 2 : 1. The stable region of each component was observed at less than 80°C in the case of HIO₃, 100190°C in the case of HI₃O₈ and more than 230°C in the case of I₂O₅. At any temperature between any two of the above mentioned degrees, the mixed components of the two were obtained. HIO₃ is obtainable, by crystallizing or drying, at less than 70°C, while HI₃O₈ is prepared if HIO₃ is either dehydrated by heating at 120150°C or evaporated to be crystallized directly from the solution at a higher temperature. Otherwise, it is obtainable if I₂O₅ absorbs water. However, the DTA curves of HI₃O₈ thus obtained are a little different from each other, and it is presumed to be caused by the structural irregularity. I₂O₅ is obtained by dehydration at a higher temperature than 230°C.

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[in Japanese]

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