The extraction of cobalt as dithizonate into carbontetrachloride was studied for concentrations of hydrogen ion, dithizone, citrate and ammonium hydroxide, and for an adequate shaking period for the extraction. The results obtained were as follows:
(1) The rate of extraction was so slow in the pH range 1.07.0, that the most prominent factor for the extractability might be considered practically to be the extraction rate rather than to be the equilibrium constant.
(2) The effect of concentrations of ammonium hydroxide and citrate ion on the cobalt extraction was smaller than that for nickel and was similar to that for cadmium.
(3) The effect of the concentrations of dithizone and hydrogen ion was considerably large.
The extraction constant (analytical) of cobalt was calculated by using saturated dithizone in carbontetrachloride in 2 hours shaking at pH 1.0, the value obtained being 5.8 × 10². Cobalt and nickel dithizonates were eluted from the alumina column of 0.7 × 5 cm, 100/325 mesh, 10% moisture content, using chloroform as an eluant, and separated from zinc and copper.
In the presence of nickel, the absorbance of cobalt is obtained to measure the absorbances at 605 mμ and 670 mμ, simultaneously. The monocolor method could be applied to microgram quantities of cobalt after removing nickel and zinc by 1 minute's shaking with hydrochloric acid (6N) followed by chromatographic separations. The absorbance was measured at 560 mμ, with a 1 cm-cell, against water blank in the final volume 2 ml. 0.25μg of cobalt could be determined by the proposed method.

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A dithizone chromatographic method had been Originally deviced to determine simultaneously the microgram quantities of nickel, cobalt, zinc and copper in rocks using less than 0.1 g samples. However the chromatographic method for copper was not practical because of the difficultness of elution.
A direct extraction photometry with dithizone from dilute sulfuric acid solution was available for the determination of trace copper in the range 1 to 40 μg in the final volume 10 ml. The extraction of copper as dithizonate into carbon-tetrachloride was studied for concentrations of sulfuric acid, hydrochloric acid and dithizone. For the trace amount of copper, conc. dithizone solution should be used for extraction from sulfuric acid solution.
The absorbance should be measured at 730 mμ against reagent blank. In the presence of 10 mg bismuth the direct extraction photometry of trace copper with dithizone (2 × 10^-3M ) from 6N sulfuric acid gave 10% lower values than that from the standard method. In the presence of 15 μg of silver, trace copper could determined by measur-ing the absorbance at 531.5 mμ as the isosbestic point.

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An universal automatic apparatus for liquid chromatography, which is equipped with a photoelectric spectrophotometer for the determination of constituents in the effluent, was presented.
The batch method, rather than the continuous flow method, was chosen for the coloration and measurement in order to use the apparatus for multiple purposes. For the measurement of light absorbance, a prism type spectrophotometer. was used to be able to determine at wavelength in the range of 2002700 mμ. The column in chromatograph portion was changeable according to the object of experiment.
Also, an automatic solvent changer was included in order to exchange the solvents in the course of chromatographic development. For the identification or the isolation of substances, the present apparatus was so designed as to be able to use an aliquot of the effluent for the quantitative determination and to collect the rest of them in a fraction collector.
An automatic operator which consisted of electronic and mechanical timers was used for systematic operation of whole apparatus.

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Ammonium phosphomolybdate as a weighing form in the gravimetric determination of phosphorus by Lieb's method is hygroscopic, and an accurate weighing of the compound is rather difficult. Studies on thermogravimetric analysis of ammonium phosphomolybdate indicated that the thermal decomposition product of the compound at about 500°C showed no more moisture absorption at the room temperature.
As the composition of this thermal decomposition product could not be made entirely clear, an empirical factor was calculated out by using potassium dihydrogen phosphate as a standard substance and a value 0.1579₂ was obtained. An outline of the recommended procedure is as follows : The sample (25 mg) is digested by heating for 30 min in 1 ml conc. sulfuric acid and 5 drops conc. nitric acid in a Kjeldahl flask, sulfate-molybdate reagent added for precipitation of ammonium phosphomolybdate.
The precipitate is filtered through a Gooch crucible, heated for 10 min at about 500°C, and the decomposition product is weighed after cooling for 25 min.

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Maximum absorption wavelengths and molar extinction coefficients of the reagents in the title and their metal complexes were determined for their carbon tetrachloride solutions. By comparing the results with those obtained, for dithizone, its bromo- and methyl-derivatives and their metal complexes, it was found that there was a certain regularity in the variations of those absorption characteristics with the introduction of functional groups.
For example, there was a clear additivity (Table II) in the shift of maximum absorption wavelength of the reagent solution by the introduction of methyl and bromo groups. Also, the comparison of reactivities of the reagents with metal ions andextraction coefficients of their mercury (II) and copper (II) complexes indicated that the dominant factor to cause the change of dithizone was the position of the introduced groups. The induction effect of an introduced group on the reactivity was not so clear.

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Maximum absorption wavelengths and molar extinction coefficients of o-iodo, p-iodo, o-iodo-p-methyl, and o-methyl-p-iodo derivatives of dithizone, and their metal complexes were measured for their carbon tetrachloride solutions, and it was found that these changes in chemical constitution were accompanied with a certain regularity in the variations of those absorption characteristics. This regularity was found to be quite the same as that found in the case of bromo and methyl-bromo derivatives in the preceeding report.
The reactivities of eath reagent with metal ions as well as the extraction coefficients of their Hg²⁺ and Cu²⁺ complexes indicated that the most prominent factor the change of reactivities of dithizone derivatives was the position of the introduced functional groups, and the methyl group in o-position had the greatest influence. However, the induction effect of an introduced group on the reactivity was not so clear.

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A method for the simultanious micro-determinations of halogens and sulfur in organic substances is described.
Sample is burned in an oxygen stream contacting with a platinum catalyst, and halogen and sulfur dioxide formed are quantitatively absorbed on the silver gauze packed in an absoption funnel. A weight gain of the silver gauze representes the amout of halogen and sulfur tetraoxide.
Subsequently, the silver gauze is electrolyzed in a known volume of solution of sulfuric acid, of which the concentration has previously been determined, and sulfate ion extracted from the silver gauze is determined by EDTA titration.

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This investigation was undertaken to develop coulometric titration with externally generated reagents. Determination of niobium with externally generated manganese(III) ion was studied.
The electrolyte composed of 0.4N manganese sulfate and 6N sulfuric acid, was introduced into an externally generating cell, manganese(III) ion being gnerated with constant current electrolysis. Niobium which had been reduced with zinc amalgam was titrated, using potentiometric end point detection. The maximum anodic current density was 5 mA/cm. Micro quantities of niobium from about 0.3 mg to 2 mg were determined with an average error of about 1%.
The method was applied to the determination of niobium in stainless steel.

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The method of extraction of beryllium-acetylacetone complex with chloroform and of spectrophotometric determination of beryllium as described by Adamso⁴⁾, Shigematsu⁷⁾ et al. has been applied for iron and steel analysis. 0.25g of sample is decomposed in 10 ml of perchloric acid, and when chromium content exceeds 3% most of it is evaporated as chromyl chloride.
The solution is diluted exactly to 250 ml and an aliquot (2 to 10 ml) is taken. 5 ml of citric acid solution (20%) and 10 ml of ethylenediaminetetraacetic acid (5%) are added to mask iron and other elements. 1.0 ml of acetylacetone aqueous solution (5%) and 10 ml of sodium chloride (20%) are added to it, and pH of the mixture is adjusted to 7.07.5 by the use of 1N sodium hydroxide. Beryllium complex is extracted with 10 ml of chloroform. Organic phase is backwashed with 50 ml of 0.1N sodium hydroxide to remove the accompanying free acetylacetone. The backwashing is done again. The light absoption is measured at 295 mμ by comparison with chloroform. Where the aluminum content exceeds 0.5%, beryllium is read a little higher, as a bit of aluminum probably forms an acetylacetonate and is extracted with chloroform.

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The authors invented an absorption photometric method for the determination of cadmium contained in cast iron by extracting cadmium as a dithizonate. The sample is decomposed by perchloric acid. After an addition of citric acid, ammonium hydroxide is added up to pH 9. Cadmium is extracted together with copper, nickel, etc., by dithizone-chloroform solution. From the extract, cadmium and zinc is stripped into 0.1N hydrochloric acid.
In order to remove zinc that accompanies cadmium, cadmium is extracted with sodium diethyldithiocarbamate-carbon tetrachloride from a solution (pH 10.5) containing hydroxylamine hydrochloride, sodium potassium tartrate, potassium cyanide, and formalin. The addition of a small amount (0.5 mg) of bismuth improves the recovery of cadmium.
Then the extract is evaporated to dryness and decomposed with nitric and hydrochloric acids. Cadmium is extracted with dithizone-chloroform form sodium hydroxide solution which contains hydroxylamine hydrochloride, sodium potassium tartrate and a small amount of potassium cyanide, and the absorbance is measured at 510 mμ. The loss of cadmium was very little in the abovementioned processes and satisfactory results were obtained.

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A new photometric method for determination of boron with rutin as a color reagent is proposed. For the determination of boron, the sample solution is evaporated with proper amounts of hydrochloric, oxalic acids and rutin reagent solutions. Then, the dried residue is dissolved with acetone, and absorbance of the solution thus obtained is measured at 440mμ. On this study, effects of concentrations of hydrochloric and oxalic acids and of rutin, drying conditions such as temperature, duration of heating and vessels for evaporation are examined respectively. It is found that Beer's law is obeyed over a range of 0.000.30 ppm of boron.
The proposed new photometric method is applied to the determination of trace amounts of boron in samples of graphite for the reactor grade.

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The method is suitable for the total carbon determination in uranium metal, the carbon content of which is from 10 γ to 1000 γ.
1 g or less of the sample of uranium metal, taken in fused silica boat, is burnt in a purified oxygen stream (60 mlper minute) within a furnace. The issuing gases and oxygen used for flushing are passed in turn through 10% platinumasbestos, silver gauze, anhydrous magnesium perchlorate layer, and finally 2 absorbing tubes, each of which contains solid sodium hydroxide and anhydrous magnesium perchlorate.
The precision attained by this method was estimated to be 1.6%, 2.6% and 3.2% in terms of standard deviation, based on 780 γ, 380 γ and 94 γ of carbon, respectively.
Analytical results for 5 uranium metal specimens are given.

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Thirty six kinds of thiazolylaldehyde derivatives were tested for the reagent for metal ions, and the limit of detection was surveyed.
Sensitive reactions were observed between oxime derivative and Pd²⁺, Cu²⁺, Co²⁺, Au³⁺, and Ni²⁺, thiosemicarbazone derivative and Pd²⁺, Cu²⁺, Ag⁺+, Hg²⁺, Au³⁺, Co²⁺, Ni²⁺, Cd²⁺, Pt⁴⁺, Zn²⁺, Bi³⁺, and Pb²⁺, 2-benzothiazolylhydrazone derivative and Pd²⁺, Cu²⁺, Ag⁺, Hg²⁺, Au³⁺, Co²⁺, Ni²⁺, Cd²⁺, and Fe²⁺, and azomethine derivative of p-aminodimethylaniline and Pd⁺, Cu²⁺, Ag⁺+, Hg²⁺, Au³⁺, Pt⁴⁺, Fe³⁺, and Cr³⁺, the limits of detection (γ/0.05 cc) being as follows : oxime derivative : Pd²⁺, 0.25; Cu²⁺, 1.0; Co²⁺, 0.075; Ni²⁺, 0.5, and Au³⁺, 2.5; thiosemicarbazone derivative : Pd²⁺, Au³⁺, and Cd²⁺, 0.25 ; Cu²⁺, 0.075; Co²⁺ and Ni²⁺, 0.025; Ag⁺ and Hg²⁺, 0.5; Pt⁴⁺ and Pb²⁺, 0.25; Zn²⁺, 0.1; Bi³⁺, 1.0 ; 2-benzothiazolylhydrazone derivative: Pd²⁺, Ag+, and Hg²⁺, 1.0; Cu²⁺, Co²⁺, Ni²⁺, and Cd²⁺, 0.25; Au³⁺, 5.0; azomethine derivative of p-aminodimethylaniline : Pd²⁺, Cu²⁺, and Ag+, 5.0; Au³⁺, Pt⁴⁺, and Cr³⁺, 2.5; Fe³⁺ and Hg²⁺, 0.5.

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Thirty three kinds of 4, 4'-bithiazole derivatives were tested for the reagent for metal ions, and the limit of detection was surveyed.
Sensitive reactions were observed between phenylimino derivative and Fe³⁺, Cu²⁺, Ag⁺, Au³⁺, and Pd²⁺, mercapto-compound and Cu²⁺, Au³⁺, Pd²⁺, Bi³⁺, Pt⁴⁺, and Pb²⁺, hydrazino derivative and Fe³⁺, Co²⁺, Ni²⁺, Cd²⁺, Cu²⁺, Ag⁺, Hg²⁺, Au³⁺, Pd²⁺, and Pb²⁺, that of 2-benzothiazolyl-hydrazino compound and Co²⁺, Ni²⁺, Cd²⁺ Cu²⁺, Ag⁺, Hg²⁺, Au³⁺, Pd²⁺, and Zn²⁺, oxime derivative and Co²⁺, Ni²⁺, Cu²⁺, Au³⁺, and Pd²⁺, semicarbazone compound and Co²⁺, Ni²⁺, Cd²⁺, Cu²⁺, Ag²⁺, Hg²⁺, Au³⁺, Pd²⁺, Bi²⁺, Pt⁴⁺, Zn²⁺, and Pb²⁺, the limits of detection (γ/0.05 cc) being as follows : phenylimino derivative : Pd²⁺ and Ag⁺+, 2.5; Fe³⁺, 5; Au²⁺, 1.0; and Cu²⁺, 0.5; mercapto compound: Au³⁺ and Bi³⁺, 2.5; Pd²⁺, 0.25; Cu²⁺, 1.0, and Pt⁴⁺, 5; that of hydrazino derivative: Pd²⁺, Fe³⁺, Co²⁺, Cd²⁺, and Pb²⁺, 0.25; Au³⁺ and Ag⁺+, 0.75; Cu²⁺, 0.05; Ni²⁺, 0.075, and Hg²⁺, 1.0; that of oxime derivative : Cu²⁺, Pd²⁺, and Ni²⁺, 0.5; Co²⁺, 0.25; and Au³⁺, 2.5; that of thiosemicarbazone compound: Pd²⁺ and Co²⁺, 0.1; Au³⁺ and Hg²⁺, 2.5; Cu²⁺, 0.075; Ni²⁺, 0.025; Cd²⁺, 0.25; Ag⁺, Zn²⁺, and Pb²⁺, 1.0; Bi³⁺, 0.5; and Pt⁴⁺, 5.0.

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Analysis of components in D-D mixture by gasliquid chromatography has been studied.
Gas chromatograms were obtained by using a stationary phase of dioctyl phthalate, tricresyl phosphate, polyethylene glycol 1000 or 6000.
Column temperature was 100°C. Helium was used as the carrier gas, flow rate 70 ml per minute.
In the case of using a stationary phase of polyethylene glycol 6000, eighteen peaks were detected. A plot of the logarithm of the retention time against the boiling point was an almost straight line.
Quantitative determination of components was carried out by internal normalization method.

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The carrier distillation method that has hitherto been used for the determination of boron in uranium has a sensitivity of approximately 0.1 ppm. The uranium samples that are available at the present time contain boron in amounts below the sensitivity. Therefore, it has become necessary to develop a more sensitive method for the determination of boron.
In the present work basic experiments have been made on carrier materials, mixing ratio of sample to the carrier material, discharge current, exposure period, atmosphere of electrode gap, etc.
As a result, it has been found that as little as 0.02 ppm of boron in uranium can be determined without a procedure of chemical concentration.

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In the determination of dissolved acetylene in solvent by polarographic method, acetylene did. not show its own reducing wave in the ordinary region under -3.0 volts. Therefore, acetylene and mercuric acetate were caused to react to% form a mercury additive compound of acetylene, its polarographic determination was investigated, and a rapid and simple method of determination. was established.
The additive compounds of acetylene and metal salts have a tendency to be precipitated in an inert solvent, while an application of these for the polarography requires a condition of no formation of precipitate. The authors found that no precipitate was formed in the additive reaction. of mercuric acetate and acetylene in methanolwater mixture by keeping the concentration of mercuric acetate to 420 mM and that of acetylene below 1/3 of mercuric acetate.
The polarogram of this solution with sodium nitrate as a supporting salt showed a wave of mercuric acetate at +0.33 volt followed by the second wave at -0.25 volt. The concentration of acetylene was inversely related with the height of the mercuric acetate wave and directly proportional to that of the second.
The second wave was originated from an additive compound of acetylene : mercuric acetate (in 1 : 3 molar ratio), and a determination of dissolved acetylene could be made within 30 min. by use of this waveheight.

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Analytical procedures for polarographic determination of hydrosulphite in the presence of sodium hydroxide have been basically studied.
Sodium hydrosulphite used as the reduction process liquid in the dye chemical industry is commonly dissolved in sodium hydroxide. This sodium hydroxide is of availed as the supporting electrolyte in the polarographic method for the sodium hydrosulphite.
The polarographic current-voltage curve of the solution containing 0.01M sodium hydrosulphite and 0.1M sodium hydrosulphite shows two oxidation waves and a reduction wave. A principal oxidation wave shows a half-wave potential of -0.45 V vs. S. C. E., the same value being observed for sodium hydrosulphite and potassium hydrosulphite in the solution.
The wave is well-defined and its limiting current is governed by the maximum rate of diffusion of hydrosulphite ions to the surface of the dropping mercury electrode. The relative error of the method is within 10% for the solutions in the concentration range from 5×10^-4M to 5×10^-2M hydrosulphites. While the concentration of sodium hydrosulphite in the reduction process liquid is usually 0.1M or more, that is too concentrated to directly apply the polarographic method, a simple procedure of dilutionwith water is served enough because 1M or more of sodium hydroxide is also contained in the reduction process liquid.
The influences of the dyestuffs, thiosulphate and other chemicals, which may by contained in the process liquid, on the principal oxidation wave of the hydrosulphite are also described.

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An automatic and continuous analyzer utilizing the polarographic method has been developed for the determination of sodium dichromate in the oxidation process liquid in chemical industry.
In the liquid, sodium dichromate accompanies commonly with sulphuric acid, and the concentration of which is also variable. However, the liquid is diluted with potassium biphthalate by means of a newly designed precise dilution device, and pH value of the diluted solution flowing through the polarographic cell is kept at 4.0.
The instrument performs a batch-type-analysis which eliminates some of the inaccuracies and sample flow-control problems, usually associated with continuous sampling. A dropping mercury electrode is employed as the working electrode in the cell, and a potential of zero volt vs. S. C. E. is applied to the electrode. Under such conditions, the cell current is governed by the maximum rate of diffusion of dichromate ions to the surface of the mercury electrode.
Accuracy and precision data from the automatic analysis are presented and the effect of the dyestuffs, chromium sulphate and other possible interfering elements on the cell current at the applied potential of zero volt are also discussed.

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When the ordinary molybdate method is applied to the determination of orthophosphate in the presence of condensed phosphates, the latter hydrolyze to form orthophosphate. In the method described in this paper, only orthophosphate is precipitated quantitatively as phosphomolybdate in the presence of condensed phosphates. Ethanol is added to a sample solution so that the ethanol concentration is kept approximately 10% in the final stage of precipitation. The ammonium molybdate reagent solution is added to this solution, and after standing 10 minutes at roomtemperature, the precipitate formed is filtered and washed with water.
The ammonium molybdate reagent is prepared by mixing a solution, which contains 80 g of ammonium molybdate in 60 ml of concentrated ammonia and 300 ml of water, with a solution containing 240 g of ammonium nitrate in 300 ml of water. A 25 ml portion of the mixture is poured into 8 ml of concentrated nitric acid immediately before use (10 ml of the reagent solution is approximately equivalent to 15 mg of P₂O₅).
After dissolving the precipitate in a known excess of alkali, the excess is back-titrated with standard acid. The endpoint corresponds to the mid-point between the discoloration point of thymolphthalein and that of phenolphthalein. By means of this method, orthophosphate containing more than 5 mg as P₂O₅ can be determined within an error of ±0.3% even in the presence of arsenate, silicate and condensed phosphates without interference.

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[in Japanese]

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[in Japanese]

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