The method for the simultaneous determination of pentachlorphenol (PCP) and tetrachlorphenol (TCP) was proposed to be used for the inspection of the atmosphere in the PCP manufacturing plant and also of urines of the workers in the plant.
The air was passed through an alkali absorbing solution and treated with potassium ferricyanide and 4-aminoantipyrin after the adjustment of pH to 7.13 with boric acid. Phenols contained in the urine interfered with the determination giving a color reaction resembling that of TCP, and should be mostly removed by the distillation of PCP or TCP from a weakly acidic solution. In the recommended procedure, the urine was distilled after an addition of citric acid, and the distillate was treated at pH 4.158 where the phenols gave only a slight coloration. The obtained color was extracted with xylene, and PCP and TCP were determined simultaneously from the absorbancies at 570 mμ and at 470 mμ, respectively.

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A method for the photometric determination of 0.010.5% zirconium in iron and steel with Arsenazo III in nitric acid solution has been studied. The absorbance in the nitric acid solution is more independent on the acid concentration than in the hydrochloric acid solution. The established procedure is as follows.
One tenth g. sample is decomposed with nitric acid and hydrofluoric acid, heated and evaporated with perchloric acid to white fumes. One tenth aliquot is taken and 50 ml of nitric acid and 5 ml of 10% urea solution are added. Ten ml of 0.1% Arsenazo III solution is added to form a blue complex and the solution is diluted with water to 100 ml. Zirconium is determined from the absorbance at 665 mμ.
The determination was carried out in the presence of iron within an absolute error of 0.005%. The time required for the analysis was about 30 min. Elements commonly present in iron and steel scarcely interfered.

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A new method for the photometric determination of 0.020.7% uranium in iron and steel with Arsenazo III has been studied. Uranium is determined after reduced to the four valence stage by the liquid zinc amalgam reduction method. The established procedure is as follows.
Two tenth g. sample is decomposed with hydrochloric acid and hydrogen peroxide. One tenth aliquot is taken and reduced in 6N hydrochloric acid for two min. by the liquid zinc amalgam. Five ml of 0.1% Arsenazo III is added to form a blue complex, and the solution is diluted to 100 ml with 6N hydrochloric acid. Uranium is determined from the absorbance at 666 mμ.
The determination was carried out in the presence of iron within an absolute error of 0.01%. The time required for an analysis was about 40 min. Elements commonly present in iron and steel except zirconium scarcely interfered.

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Vanadium reacts with 4-(2-pyridylazo) resorcinol (PAR) to form a water-soluble red complex. The complex has an absorption maximum at 545 mμ with a constant absorbance at pH 5.256.50 (in the solution with phosphate buffer).
The reaction is very sensitive. The molar absorptivity of the complex is ca. 35, 000. The mole ratio of V and PAR is 1: 1. Many of the metal ions interfere, but Al, Ba, Sr, As, Ce, Mo, Mg, Pt, Be, Re, W, La, Ca, Sb, etc. scarcely interfere even when their amounts are four folds of vanadium. The Beer's law is obeyed in the range 0.11.0 μg V/ml.

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A micro amount of cesium is extracted by benzene as its salt of tetraphenylboron (TPB) from the solution with pH higher than 2. An addition of calcium ion prevents the emulsification. The interference from the trace of potassium can be avoided by the use of a mixture of benzene and methyl isobutyl ketone.
The extraction with methyl isobutyl ketone alone is successful only from the solution of much higher concentration of TBP. The radioactive ¹³⁴Cs added to a solution (pH 5) from pitchblende (corresponding to 20 mg of U) was recovered quantitatively by the extraction with mixed benzene and methyl isobutyl ketone (1+1).
Francium and thallium are extractable under the same conditions as those for cesium.

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Based on the principle that cholesterol was oxidized into cholest-4-en-3, 6-dione and the derived p-nitrophenylhydrazone was able to give an intensive and stable color reaction showing maximum absorption at 585 mμ, the determination of 550 μg of serum cholesterol has been investigated and a new colorimetric method was presented.
Serum cholesterol was extracted with the mixture of acetone and alcohol (1: 1) and the extract in an acetone solution was oxidized by the Kiliani's reagent at 0°C for 20 minutes. After excess amounts of chromic acid were destroyed by adding sodium bisulfite (aqueous solution), the oxidation product was extracted with carbon tetrachloride. The lower layer thus formed was evaporated into dryness and the residue was reacted with p-nitrophenylhydrazine reagent at 60°C for 60 minutes. After cooling the reaction mixture of sodium hydroxide (aqueous solution) and dimethylformamide were added to make color which showed an optical density proportional to the initial amount of cholesterol presented in the serum.
It has been found that free cholesterol could be determined specifically even in the presence of esterified cholesterol which gave no color under the proposed procedure in this paper. Total cholesterol in serum could also be determinated by the same method after hydrolysis of ester cholesterol in the extract.

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In the study of thallotoxicosis, it has become necessary to determine accurately a low thallium content of urine. A method has been developed for the determination of thallium with malachite green. After wet ashing of the urine sample by conc. nitric acid, the residue is dissolved in hydrobromic acid and saturated bromine water is added to oxidize thallium to the trivalent state. Thallium is extracted with isopropyl ether from a 0.51.0N hydrobromic acid solution. The aqueous phase is discarded, and the organic phase is evaporated.
The residue is dissolved in 10 ml of 1.5 N hydrochloric acid and the solution is transferred to a separatory funnel. One ml of 0.2% Malachite Green solution and 10.0 ml of benzene are added, and the system is shaken for 30 sec. The organic phase is centrifuged, and the absorbance is measured at 635 mμ. Known amounts of thallium added to urine sample were recovered satisfactorily by this method.

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Studies on the thermal decomposition of ammonium hypophosphite in nitrogen atmosphere under various conditions were carried out. The thermal decomposition products obtained were different from those in the literature.
The compositions of the products depended greatly on the conditions of decomposition. The products obtained at relatively low temperature (250°C) showed comparatively high concentration of orthophosphoric acid, and its value rapidly decreased with increasing duration and temperature of the thermal treatment, while the concentrations of the polyphosphoric acids, pyro-, tri-, tetra-, etc., increased. These were indicated not only by the increase of the total concentration of phosphorus pentoxide in the products, but also by the fractional elution of each polyphosphoric acid using ion-exchange resin, Dowex-1. Conclusively, it is assumed that a relatively large amount of orthophosphoric acid is produced in the early period of decomposition reaction and the dehydration reaction follows, of which rate is accelerated by the elevation of temperature.

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Isotopic balancing-spectroscopic method developed by Zaidel' is applied to the determination of hydrogen in uranium metal. Uranium metal is heated in a quartz exchanger vessel with deuterium gas for the isotopic balancing. Heating at 1000°C for 30 mimtes is necessary for the attainment of equilibrium. For the spectroscopic analysis of hydrogen-deuterium mixtures, a 27-megacycle electrodeless discharge is used as the light source.
The Fabry-Perot interferometer with a narrowband interference filter is employed for recording of the spectrum H_β and D_β. The relative error is 3 to 7% for hydrogen contents between 5 and 0.5 ppm in the sample of 17 g. The time required for an analysis is 50 to 60 minutes.

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Several supporting electrolytes have been tested for square-wave polarographic determination of trace amounts of titanium.
When mineral acids of various concentrations were added to tartaric acid solutions, the aspects of variance of titanium wave height were different with species of the mineral acids. The calibration curves of titanium in 1M of tartaric acid and 0.1M of various mineral acid solutions were almost linear, but the reproducibilities were not so good.
While, when the sodium citrate as supporting electrolyte was used, good results were obtained at 0.5 to 0.7M of sodium citrate solution of pH 5.8 to 6.3, and calibration curve was linear in the range of 2.5×10^-6 to 3×10^-5M of titanium Concentration.
Diverse metals such as potassium (sulfate, chloride, nitrate), copper, antimony (III), bismuth and lead did not interfere, but molybdate and phosphate interfered the determination.

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Small amounts of zinc in cement was determined by A. C. polarographic method. The procedure estabished is as follows. A sample is dissolved in hydrochloric acid with ammonium chloride, and silica, being made insoluble, is filtered off. Zinc in the filtrate is extracted in benzene as dithizonate, followed by stripping into phosphoric acid solution.
The resulting solution is adjusted to 1.0M as phosphoric acid. The dissolved oxygen in an aliquot taken is removed completely by passing N₂ gas, and A. C. polarogram is obtained between -1.0 to -1.5 volt against Hg pool, and the amount of zinc is obtained from the calibration curve.
As little as 0.001% zinc in cement was deter. mined with satisfactory results, and about 0.010.1% of zinc was found in the commercial products.

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A method is described for the analysis of minute amount of permanent gases by gas chromatography, using a 1.5 m molecular sieve 5A column and a radioactive ionization detector with RaD source. Argon containing organic vapor and helium were used as a carrier gas and the calibration curves for various gases were measured by each carrier. Naphthalene was very good organic vapor source in argon carrier method. But this detector is very sensitive to the contamination such as organic substance and the sensitivity for various gases changed irregularly with the quantity of the contamination.
Therefore the quantitative result could not be obtained by these methods based on the ionization current reduction due to the sample gas. Finally it was found that helium was the best carrier but any of the contamination and impurities in it should be eliminated. Under this condition, permanent gases including neon are determined in the range about 11000 ppm as the ionizaticn cnrrent increase, and their minimum detectable amounts are 0.10.01 μl.

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