Conditions were described for the determination of extremely minute amounts of cadmium by a dithizone extraction method. The factors investigated included the concentrations of dithizone, hydrogen ion, ammonium hydroxide, sodium hydroxide, zinc and cyanide ion, the volumes of organic and aqueous phase, and the sorts of solvent.
The selected and recommended conditions were as follows : The cadmium was extracted with twice 10 ml of dithizone (1×10^-4M) in chloroform from 50 ml of the sample solution containing 3ml of 0.1M potassium cyanide adjusted at pH 10 with ammonium hydroxide, the chloroform extract washed with 10 m/ of water and stripped with 20 ml of 0.1N hydrochloric acid, the aqeous phase washed with chloroform, and the cadmium dithizonate extracted with 25 ml of dithizone (2× 10^-5M) in chloroform from 70ml of 1N sodium hydroxide solution containing 0.5 ml of 20% ammonium citrate and 0.5ml of 0.1M potassium cyanide. The absorbance was measured at 518 mμ. 0.06 ppm of cadmium was found in a sample of lava from Mihara, volcano, Japan, using 2g rock samples.

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2-Benzothiazolylaldehyde-2-benzothiazolylhydrazone (B. B. T. H.) and 2-α-naphthothiazolylaldehyde-2-benzothiazolylhydrazone (N. B. T. H.) gave orangered orange coloration with Cu²⁺, Co²⁺, and Ni²⁺. Two cc of sample solution [Cu²⁺=pH 4.00 (B.B.T.H.), pH 5.42 (N. B. T. H.); Co²⁺=pH 8.00 ; Ni²⁺=pH 5.42] were treated with 0.075% B. B. T. H. or 2 cc of 0.05% N. B. T. H. dioxane solution, and 1 cc dioxane was added to make up the whole volume to 5 cc.
Quantitative determination was applied by the estimation of light absorbancy at λ_max. of each complex (464 mμ for Cu²⁺, 462 mμ for Co²⁺, and 468 mitt for Ni²⁺ with B. B. T. H. ; 476 mμ for Cu²⁺, 475 mμ for Co²⁺, and 474 mμ for Ni²⁺ with N. B. T. H.). The measurement should be made for Cu within 10 min after the reaction, and for Co and Ni after 10 min or more of standing. By this method, colorimetric determinations of 0.255.05 r/cc of Cu²⁺, 0.15.2 r/cc of Co²⁺, and 0.12.9r/cc of Ni²⁺ was possible. Zn²⁺ and Pd²⁺ interfered with the determinations.
The molecular absorption coefficient of Cu²⁺ with B. B. T. H.=3.251×10⁴, Co²⁺ with B. B. T. H.=5.799×10⁴, and Ni²⁺ with B. B. T. H.=6.024×10⁴, that of Cu²⁺ with N. B. T. H.=4.126×10⁴, Co²⁺ with N. B. T. H.=5.533×10⁴, and Ni²⁺ with N. B. T. H.=6.395×10⁴, with the indication that these are very sensitive reagents.

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Reaction of 2-benzothiazolyl-phenylketoxime with Co²⁺ gave a yellow-orange coloration and that with Cu²⁺ and Ni²⁺ gave a yellow coloration. Two cc of sample solution in a 5 cc measuring flask were treated with 0.5 cc ammonia-ammonium chloride buffer solution of pH 9.00, 1 cc 0.2% ethanolic solution of the reagent and 1.5 cc dioxane, made up to 5 cc, and the light absorbancies at 362mμ for copper, 358mμ for cobalt, and 356mμ for nickel were measured after standing for 30 min, running a blank consisting of the same amount of the reagent, the buffer solution, ethanol and water at the same time.
By this method, estimation of copper in the range of 0.2520.20γ/cc, cobalt in the range of 0.110.65γ/cc, and nickel in the range of 0.2510.40γ/cc was possible.
Also, selective determinations of copper, cobalt and nickel from their mixture were possible by selecting the pH and the wavelengths as 400mμ or 445mμ. The presence of palladium, and cobalt for determination of copper, that of palladium and silver for cobalt, and that of iron, palladium and cadmium for nickel had disturbing influences. The molecular absorption coefficient was 1.303×10⁴ for copper, 2.178×10⁴ for cobalt, and 1.899×10⁴ for nickel.

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Mercury complex of bis (2-hydroxyethyl) dithiocarbamic acid (BHDTC) was demasked by cyanide in the presence of citrate buffer, giving equivalent free BHDTC which reacted with copper ion to form a soluble complex with yellow coloration. The fact was applied for an indirect photometric determination of cyanide, and the conditions for the determination were investigated. The copper complex thus formed showed a maximum absorp tion at around 383 mμ and its constitution determined by the continuous variation method was 1:1 for BHDTC and copper.
The light absorbancy measured by use of a 383 mμ filter was stable at least for 3 hours and the value was almost constant in the pH ranges 5.45.7. Although the calibration curve slightly differred from that expected by the Beer's law, a simple determination of cyanide ion in the concentration ranges of 0.24 ppm was possible. The sensitivity of the method was 0.0054γ/cm². Fe³⁺, Hg²⁺, I^-, and S₂0₃^2-interfered, but 20, 000 ppm of Cl^-, 120 ppm of SCN^-, 200 ppm of Br^-, and 400800 ppm of Cd²⁺, Mn²⁺, Pb²⁺ and Zn²⁺ showed no effect against 2 ppm of CN^-.

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Coulometric titration of sodium tetraphenyl borate, which was a specific precipitant for potassium, was studied for the determination of micro quantities of potassium.
Using an electrolyte composed of 60% acetone, 0.5M sodium nitrate, and 0.02M acetic acid, tetraphenyl borate could be determined coulometrically with electrolytically generated silver ion from silver electrode. The end point detection was carried out with amperometric or potentiometric method. In the amperometric method, 250 mV were applied between the indicator electrodes. Sodium tetraphenyl borate from 9 to 36 mg was determined with an error of less than 1%.
The recommended procedures for the potassium determination were as follows : potassium was precipitated with tetraphenyl borate, and after the precipitate was dissolved in acetone, potassium was determined by coulometric titration of tetraphenyl borate in acetone solution (method A). Potassium was also determined by another method B; i. e., potassium was precipitated with the known amount of the precipitant, and after the precipitate was filtered off, the excess amount of the precipitant in the filtrate was titrated. Potassium from 1 to 4 mg was determined by both methods, with an error of less than 1%.
The method A was applied to the determination of potassium in industrial salt.

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An improvement of the vapor-chromatographic apparatus in the preceeding report was made, its operation was simplified for the determination of inorganic and organic acids by use of diethylamine, and the reaction by the passage of steam through the column was investigated.
Inorganic or organic acid was dissolved in an excess of diethylamine, held by a column (clean sea sand) in the apparatus, and steam was passed through, keeping the temperature of the column at 100°C or above for distilling off the excess of diethylamine or that remained unreacted with the acid. The distillate was absorbed in boric acid solution and titrated with N/20 sulfuric acid using a micro burette with methyl red as an indicator. The amount of acid was calculated from the amount of diethylamine consumed.
The result indicated that the quantitative reaction took place with acids having dissociation constants larger than 5×10^-5. For a polybasic acid having two or more dissociation constants one of which was larger than 10^-4 and the others of which were less than 10^-7 (such as phosphoric acid), or for a mixture of the two acids each dissociation constant of which was wide apart as such, a selective determination of the acid with value larger than 10^-4 was possible (Table II and III). Since the titration was made only for the excess of diethylamine, the result was not affected by the buffer action of diverse salts and the end point was very clear.

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The author developed an apparatus(Fig.2)for the determination of a micro quantity ofwater in gaseous sample, such as oxygen, nitrogenand gaseous hydrocarbon, Using the Karl Fischerreagent(0.51.0mg H₂O/ml).It contained 100ml of anhydrous methyl alcohol.The gaseoussamples passed through it of the velocity below1l/min, and the water in the sample was perfectly trasferred into it, and titrated as usual using the same vessel. By the proposed method, the time required for an analysis was shortenedabont by half, the operation became very simpleand very accurate results were obtained.
An example showed that the time required toanalyze a sample of nitrogen gas(the watercontent was0.004%)was about one hour andthe precision was good(Table V, No.4, 5, 6).

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Determinations of 2-methyl-5-vinylpyridine, 2-vinyl-5-ethylpyridine, and 2-vinylpyridine by use of near infrared absorption have been devised for the manufacturing process controls. Since these vinylpyridines show characteristic absorptions at 6130 cm^-1, 4700 cm^-1, and 4480 cm^-1, respectively, they are placed in quartz cells of 1 mm light path, and the quantitative determintions with variation coefficient 0.95% are succesefully carried out by recording the spectra in these regions.
The moisture content can be determined at the same time. This method can be applied on samples of wide ranges and useful as an industrial method with rapid and simple operations.

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Gas chromatography, using a column packedwith 33% dioctyl phthalate and 1% phosphoric acid on C-22, was shown to be a useful method for the rapid determination of monochloroacetic, dichloroacetic and acetic acid in the crude liquid.
By the use of the column recommended, a complete separation of the three components was achieved, and the time required for elution was 50 minutes.
The column was held at 130°C, and the flow rate of carrier gas (He) was adjusted to 100ml/min. Each component was determined from relative area of the peaks compared with that of monochloroacetic acid. The results obtained agreed well with those obtained by the chemical methods.

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A new method of detecting zinc ion has been investigated. The present method using diethylaniline and potassium ferricyanide is inevitably affected by many various oxidants. In order to improve the shortcoming, thiourea and rhodamine B have been adopted by the author in the place of diethylaniline; that is, in the presence of thiourea, zinc ion with potassium ferricyanide does not produce yellowish brown zinc ferricyanide, but white zinc ferrocyanide, which adsorbs rhodamine B and exhibits a purple coloration. This purple precipitation is specific for zinc ion only.
The recommended procedure is as follows; to a neutral or slightly acidic test solution which is supposed to contain zinc ion, 1M thiourea solution and 0.5% rhodamine B solution are added and stirred well, and 0.05M potassium ferricyanide solution is added drop by drop, with constant agitation. When zinc ion is present, a purple precipitate is formed.
This method also can be applied to in spot test, when the limit of identification for zincion by this method is 2γ per drop of the test solution.

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Fifty ml of a sample solution are placed in a decomposition flask as shown in Fig. 1, heated with sulfuric acid for decomposition of xanthate, and the product is taken out as carbon disulfide. This is absorbed in an ethanolic solution of potassium hydroxide for regeneration of the xanthate, and placed in a separatory funnel adjusting pH of the solution to 6.0. The solution is treated with nickel sulfate, the nickel xanthate thus formed is extracted with carbon tetrachloride, and the light absorbancy at 420 mμ or 320 mμis measured (absorption spectrum of nickel xanthate is shown in Fig. 2).
The method is rapid and simple, and shows a high reproducibility. By this method, 0.00010.01 g/l of xanthate can be determined within 60 min., in the presence of 0.01 ml pine oil, 1 mg paifloat, 50 mg calcium hydroxide, and 1 mg copper as copper-cyano complex. Analyses of many samples can be made at the same time within 30 min. by means of direct extractions, when they do not contain copper ion.

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Uranium metal is dissolved in 5N HC1 with H₂O₂, and U is separated out of the solution by tributylphosphate extraction. The aqueous solu tion containing Th is evaporated to 12ml, Sr solution added as an internal standard, and the whole is absorbed in 6 sheets of filter paper. The fluorescent X-ray analysis is developed for the filter paper containing Th. The spectra of ThL_α1, SrK_α, etc. are recorded in a chart and their intensities (I_Th and I_Sr) are measured from their peak heights.
In spite of bad reproducibility obtained for the absolute intensity, reproducibility of the intensity ratio shown by I_Th /I_Sr was good, and if theapplied voltage was more than 35 kV, the effect of different voltage or current was not significant. The working line obtained by plotting intensity ratios versus quantities of Th was not straight in its low concentrations. Less than 20 mg of U did not give an error to the determination, if present by the intensity measurement. A slight lack of uniformity of Sr and Th in the filter paper was not significant. The analysis of a uranium metal for the nuclea fuel containing 0.047% Th showed σ=0.002% Th, for 0.61g samples. The values agreed with those obtained by the previously reported solution method or the colorimetric method.

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A fluoresent X-ray analysis was successfully applied to determine the silicic oxide and aluminum oxide in cements and their raw materials.
The measurement was performed with a Rigakudenki X-ray Spectrograph, and silicic oxide and aluminum oxide were determined with ammonium dihydrogen phosphate (d=5.324Å) as an analysing crystal in a helium atomosphere bymeans of a gasflow proportional counter and a pulse height analyser.
Calibration curves were prepared from the synthesized powder specimens and commercial cements of which the contents of silicic oxide and aluminum oxide were previously known.
Each of the powder specimens was compacted into a pellet by a press at 300 kg/cm² so as to avoid an error caused by the ununiformity in the packing.
The measurement was carried out by comparing the intensities of SiKα and AlKα in the unknown with those of the standard at every determinations. Polished piece of basalt was employed as the standard in the experiment.
By the above-mentioned method and the calibration curves, standard deviations for the analytical values were 0.38% for silicic oxide and 0.28% for aluminum oxide respectively. Differences between the results obtained by the fluorescent X-ray method and those by the chemical analysis were 0.13% for silicic oxide and 0.20% for aluminum oxide.
A complete determination of these two elements in one sample was made in ten minutes, and the method can be used as a rapid analytical means of quality control in cement industries.

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Polarographic determination of dissolved tin in orange juice were made on 80 kinds of sample in tin cans on the market. The results indicated that some of them contained 150 ppm or more of Sn. Studies were made on the solubilizing condition of tin by using carefully prepared samples under different conditions. No significant difference in Sn dissolution was caused by the variations of
(1) the sort of tinned iron as H-D or E-T,
(2) the amount of vitamin C added; while
(3) packing temperature,
(4) numbers of month of storage, and
(5) anticorrosive film coating on inner surface of the container gave 95% significant differences on the Sn dissolution. There was no remarkable correlation between the amount of dissolved Sn and the lowering of degree of evacuation, provided the Sn concentration was below 150 ppm (the limit permitted).

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Metallic uranium was decomposed in 1 : 1 hydrochloric acid in a polyethylene beaker and dissolved completely by use of hydrogen peroxide. This was concentrated by evaporation, redissolved in hydrochloric acid, and uranium and ironwere removed by extraction with TBP-carbon tetrachloride solution. The TBP in aqueous layer was removed by washing with carbon tetrachloride.
After the aqueous solution was evaporated to dryness, the residue was made slightly acidic with hydrochloric acid, heated with oxin solution, adjusted to pH 67 by addition of ammonium chloride-ammonium hydroxide with further heating, and the complex oxin salt was removed by washing with chloroform. The aqueous layer was treated with phthaleincomplexone and potassium cyanide solutions, and adjusted to pH 10 with ammonium chloride-ammonium hydroxide. The light absorbance at 570 mμ was measured, and magnesium was determined from calculation by use of a calibration curve.

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Detailed practical investigations have been made for volumetric determination of total titanium in titanium metal or titanium tetrachloride, and the following results were obtained.
(1) For the dissolution of the titanium metal, hydrofluoric acid+ sulfuric acid was most suitable, since the dissolution was done quickly and easily controlled, besides it gave the same result as that obtained by the usual method (Table I). In case of single use of hydrofluoric acid for taking up, an interference was observed for titration (Table II).
(2) The dissolution of titanium tetrachloride was more preferably done by hydrochloric acid than by sulfuric acid. A definite amount of sample was taken with an injector and was transferred into the acid solution without loss in the dissolving process.
(3) The liquid zinc amalgam reduction was superior than the other methods in respect to the time required and the simpleness of operation (Table III). The simpleness was further increased by the respective uses of a special separatory funnel with a branch [Fig. 1 (a)] as the reduction vessel and carbon tetrachloride for separation of amalgam after reduction.
(4) The reduced solution from titanium metal or titanium tetrachloride prepared by the above process could be titrated with usual ferric ammonium sulfate solution, provided the sample contained no vanadium.
(5) Although vanadium in the titanium tetrachloride sample interfered with the reduction and titration in the method described above, it was possible to calculate the real quantity of titanuim, without a prior separation of vanadium, provided the vanadium % of the sample could be obtained by any analytical method.

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After the comparisons of various procedures and conditions for reaction in the quantitative determination of tin, by application of reducing action of Sn (II) for formation of molybdenum blue, the hitherto known method has been improved with the most suitable conditions.
The development of blue coloration was indicated in Fig. 1, the change of the concentrations of potassium dihydrogen phosphate and ammonium molybdate with a fixed concentration of sulfuric acid at 3.6N. Also, the development of coloration with different concentrations of sulfuric acid was indicated in Fig. 2.
It was found that the suitable concentrations of reagents for development of coloration were 3.6N for sulfuric acid, 0.4% for potassium dihydrogen phosphate and 0.4% for ammonium molybdate.
The coloration was reproducible provided the concentration of tin was within the range of 015ppm. The reduction of tin was suitably made by using metallic alminum of ca. 99.8% purity.

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Effect of the diverse ions in the determination of tin by the molybdenum blue method, reported in the preceding paper, has been investigated.
As a means for the separation from disturbing ions, coprecipitation with manganese dioxide was applied for determination of tin in water, brass and steel.
In the case of steel, where a reprecipitation was inevitable, it was also necessary to take a fairly large amount of sample at first, and to take an aliquot before reduction in order to avoid the iron contamination.
For the determination of tin in water, the coprecipitation with manganese dioxide was also useful as a means for the concentration of tin.
100500γ of tin could be determined by the proposed method with satisfactory results.

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