As a hygienic chemical study on the treatment and on the influence of selenium to humans, microdetermination of selenium in various kinds of sample was investigated. Selenium (IV) in the sample was converted to selenium (IV) by heating in hydrochloric acid of concentration above 17%. Treatment of selenium (IV) by heating in hydrochloric acid of concentration above 17%. Treatment of selenium (IV) with 4-chloro-o-phenylenediamine at pH 1 in a boiling water-bath gave 5-chloropiaselenol quantitatively. 5-Chloropiaselenol thus obtained was extracted with benzene at pH 1 and determined by ECD gas charomatography with 15% OV-17 Chromosorb W. High sensitivity of this method enables determination of 0.05 ppm of selenium and the calibration curve is linear up to 0.8 ppm. This microdetermination method is considered to be applicable to various kinds of samples such as river water, food, and animal tissues.

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An improved method was devised for chemical assay using dithizone for determining Thimerosal (sodium ethylmercurithiosalicylate) as an antiseptic in biological products. This method uses direct determination of the amount of Thimerosaldithizone complex, after removing unreacted dithizone in the reaction mixture by aqueous ammonia. The results showed that the present chemical method is better than the biological assay.

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In connection with the manifestation of Minamata disease-symptoms by methoxyethylmercuric chloride reported previously, toxicity of several alkoxyethylmercury compounds was examined. A diet mixed with hydroxyethylmercuric, acetoxyethylmercuric, or alkoxyethylmercuric chloride was fed continuously to dd strain male mice and, also to test distribution of mercury in organs of mice, alkylmercury, phenylmercury, alkoxyethylmercury, or inorganic mercury compound was administered orally once a day for 5 days. Mercury content in organs was estimated at 253.7 mμ by atomic absorption spectrophotometry after reduction of mercury (II) to metallic mercury by tin (II) after wet digestion of the samples with hydrogen peroxide and sulfuric acid. Specific neural symptoms were observed in almost all the mice given EEMC in doses of 2000 and 2500 μg Hg/day. Mercury content in the organs of these mice was the highest in the liver and the kidney, and 20 μg Hg/g tissue in the brain. Mice given longer-chain alkoxyethylmercury compounds died or showed collapse without such symptoms. This was associated with the increase of acute toxicity according to the number of carbon atoms in the alkoxy group. Comparison of the distribution of different mercury compounds in organs showed that the accumulation of mercury was high in all organs examined in the case of alkylmercury compounds, and decrease of mercury from the organs was slow, but in the case of alkoxyethylmercury compounds, accumulation of mercury was highest in the kidney and lower in other organs, and the decrease of mercury from the organs was rapid.

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Hydrocarbons in atmosphere was determined by the use of an apparatus usually used for the elemental analysis of carbon and hydrogen in organics. The characteristic feature of this process is its simplicity of being able to make the determination by introduction of the test gas into the conventional carbon-hydrogen analysis apparatus. The amount of hydrocarbons present in air can be calculated from the analytical values of carbon and hydrogen.

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A method for the determination of methylmercury has been improved by adding several steps to the ordinary process, such as the proteinase digestion of the samples and continuous extraction of the digest with benzene, and by utilizing p-nitrobenzyl chloride as an internal standard in gas chromatographic analysis. The method thus modified eliminated the emulsion formation, one of the most serious troubles in ordinary method, throughout the whole procedure. The new method revealed 93% of average recovery and less than 1.7% of deviation. The improved procedure was used to estimate the ratio of methylated mercury to total mercury in tuna fish and the results are presented.

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Methods are described for the gas-liquid chromatographic estimation of cinchophen, sodium salicylate, aminopyrine, and isopropylantipyrine in drugs. Dioctylphthalate was used as internal standard. Before chromatography sodium salicylate was converted to an O-capryl ester with capryl chloride, and to an O-methyl ester with diazomethane, and cinchophen was converted to the same O-methyl ester as sodium salicylate. Aminopyrine and isopropylantipyrine was not affected by the above conditions for conversion to the O-derivatives. Cinchophen and sodium salicylate, aminopyrine and isopropylantipyrine were determined simultaneously and rapidly without any additional separatory operations.

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A rapid determination of microamount of mercury by a combustion flask using the oxygen cylinder combustion method was examined. In this method, after the sample is burnt in an oxygen-filled flask of 500 ml capacity, mercury is absorbed in a solution of 20 ml of 2.0 N H₂SO₄ and 20 ml of 0.3% KMnO₄ solution. This absorbed mercury is converted into mercuy vapor by reduction with SnCl₂, and is determined by atomic absorption spectrophotometry. At 2 ppm of mercury in a fish meal, it's recovery rate was 98% in average, and at 1 ppm of mercury in fish meat, it's standard deviation was 0.028 ppm. When using two combustion flasks, amount of mercury in the samples can be determined at the rate of only 5 min per sample.

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Coagulations of paper mill wastes were investigated by the use of polyelectrolytes. Nonionic polyacrylamide was the most effective for the purification of wastes. The suspension of pulp fiber was rather dispersed by the addition of anionic polyelectrolytes, such as sodium carboxymethyl cellulose, sodium alginate, and sodium polyacrylate. No remarkable effect of pH was seen for the coagulation of polyelectrolytes. The possibility to using polyelectrolytes for the purification of paper mill wastes was recognized in the case of the wastes suspending large fibrous colloid.

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An ion exchange method is described for the separatory detection of a microquantity of coal-tar dyes in cosmetics which contain a large quantity of anionic surfactant. In this method, a sample (3-5g) is warmed on a water bath to remove volatile components and then dissolved in 20 ml of ethanol. The ethanol-soluble portion is passed through a column of 10 ml of DEAE-Sephadex A-25, and then the column is washed with 100 ml of 30% ethanol. The dyes are eluted with hydrochloric acid-30% ethanol mixture (1 : 9), at a flow rate of 0.4 ml/min, until they have completely been eluted. The effluent is evaporated on a water bath, the residue is dissolved in 1-2 ml of ethanol, and this ethanolic solution is submitted to thin-layer chromatography for the identification of each dye. This method was found to give a satisfactory result in the detection of a microquantity of coal-tar dyes in various cosmetics, shampoo, and kitchen-use liquid detergents containing a large amount of anionic surfactant.

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An analytical method is described for the detection of inorganic mercury, alkylmercury, alkoxyethylmercury, and phenylmercury dithizonates on commercially available Avical SF thin-layers coated with liquid paraffin. The compounds examined were distinctly separated with high reproducibility of Rf values. From biological samples to which mercuric compounds were added as a chloride, the compounds were isolated as the dithizonates by extraction of the samples with dithizone-carbon tetrachloride solution and subsequently the dithizonates were purified by column chromatography using alumina. When the dithizonates were applied to reverse-phase thin-layer chromatography, the compounds were detected even at a low level.

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The paper electrophoretic method for identification of alkaloids (nicotine, quinine, pilocarpine, atropine, scopolamine, strychnine, papaverine, brucine, narcotine, aconitine, berberine, caffeine) and a related compound (procaine) was investigated by using 5 N acetic acid, 0.1 N phosphoric acid and 0.1 N disodium hydrogen phosphate as the electrolyte. The mobilities of the compounds were expressed relative to auramine. It was found that all the alkaloids and the related compound tested in this study could be separated and identified by selecting one of the suitable electrolyte from the above three.

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It was found that color intensity of the complex between mercury (II) and thiothenoyltrifluoroacetone (STTA) is suppressed in the presence of thiocyanate ion. This suppression was applied to the determination of a small amount of thiocyanate ion in the solution acidified by sulfuric acid. The proposed method covers a concentration range of 5-60 μg of thiocyanate ion in 10 ml solution. The coefficient of variation was 2.1, 2.0, and 1.1% for 10, 30, and 50 μg of thiocyanate ion, respectively. The analytical procedure proposed is as follows. Eight milliliters of a sample solution containing 5-60 μg thiocyanate ion and 2 ml of 10 N sulfuric acid are placed in a test tube with a ground-glass stopper, 10 ml of mercury (II)-STTA complex solution containing 40 μg mercury (II) in carbon tetrachloride (10 ml) is added, and the mixture is shaken vigorously for 2 min. The organic layer is separated, washed successively, with 10 ml each of water and pH 11.5 washing solution, and dried over anhydrous sodium sulfate. The absorbance of mercury (II)-STTA complex in the organic layer is measured at 360 nm against carbon tetrachloride. Examination of the effect of co-existing anions showed that sulfide, iodide, and iodate interfered even in one-tenth the amount of thiocyanate ion. The proposed method was applied to the determination of thiocyanate ion in human saliva.

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