A method was investigated for detection of chloramphenicol in foods by thin-layer chromatography. This method is composed of the following steps : Initial extraction of chloramphenicol from foods into suitable solvents, isolation of the compound from other interfering materials by alumina cleanup, and detection of chloramphenicol by thin-layer chromatography using silica gel. When the method was applied to milk, egg, and chicken to which the antibiotic had been added at levels of 0.1-1.0 ppm, the detection limits were 0.2, 1.0, and 0.5 ppm, respectively. It was moreover found that chlorinated pesticide residues in foods did not interfere with this detection.

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The color of the complex between mercury (II) and thiothenoyltrifluoroacetone (STTA) is suppressed in the presence of sulfide ion. This inhibitory effect was applied to the spectrophotometric determination of 0.3-6.45 μg of sulfide ion in 10 ml solution. The molar extinction coefficient was about 32000. The precisions in coefficient of variation were 2.3 and 1.1% for 2.15 and 4.30 μg, respectively, of sulfide ion. An analytical procedure for sulfide ion was as follows. Several milliliters of a sample solution containing 0.3-6.45 μg sulfide ion and 2 ml of borate buffer (pH 11.5) are placed in a test tube with ground glass stopper, and the solution is made up to 10 ml with water. Ten milliliters of mercury (II)-STTA complex (containing 40 μg mercury (II) per 10 ml) in carbon tetrachloride is added to it, and the mixture is shaken vigorously for 2 minutes. The absorbance of mercury (II)-STTA complex in organic phase is measured at 360 nm against carbon tetrachloride. Many kinds of anions did not interfere in this determination. Cyanide ion interfered slightly even when the amount was 1/4-fold of sulfide ion. The permissible amount of cyanide ion was slightly increased by pH 10.0 borate buffer. The proposed method was selective and sensitive, and good results were obtained for the analysis of natural water mixed with known amounts of sulfide ion.

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Effect of cationic surfactants, amines, and polyelectrolytes on the dissolved-air flotation of colloidal suspensions was investigated. Cationic surfactants were effective agents for the removal of diatomaceous earth colloids, but the amines and polyelectrolytes were not effective. Particularly, octadecyl dimethyl benzyl ammonium chloride and 2-heptadecyl-1-(2-hydroxyethyl)-ethyl-imidazolinium ethyl sulfate were the most effective agents as flotation aids. These surfactants were also effective for the purification of various kinds of water, such as river water, ferric oxide suspension, kaolin suspension, lake water containing phytoplankton and waste from iron foundry.

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Whole body turn-over and excretion of selenium administerd in the form of sodium selenite and L-selenocystine to rats were examined over a prolonged period. Radioactive sodium selenite and L-selenocystine were dissolved in their carrier solution (0.005 mg/ml of Na₂SeO₃ and 0.05 mg/ml of L-selenocystine) to have a radioactivity of 1 μCi/ml. One ml of this solution was given orally, subcutaneously, or intravenously to each group consists of 3-4 rats, and the radioactivity in the whole body of living animals, feces, and urine was measured every day up to approximately the 50 days after dosing, using a Packard ARMAC scintillation counter. The whole body count of living animals given two kinds of selenium compounds by three different routes of application fell down relatively rapidly in about the 10 th day, but thereafter the radioactivity decreased very gradually and about 3% of the initial whole body count was still retained about the 50 th day after dosing. It was noted that the whole body count decreased exponentially during the time from the 1 st day to the 10 th day and from the 10 th day to the last day after administration, so the linear retention lines of selenium were depicted graphically on semilogarithmic scale, respectively. Biological half-life of selenium compounds absorbed in the whole body was found by statistical calculation from the linear retention lines, and the results were as follows : about 6 days in the former phase of excretion, about 18 days in the latter phase. There was no difference in biological half-life according to the chemical form of selenium and the route of application. The rats were dissected and radioactivity in some of internal organs was measured to know the distribution of residual selenium 40-50 days after dosing. Trace amount of two kinds of selenium compounds given by three different routes of application persisted in blood, liver, and kidneys for a long time. No significant accumulation of selenium was observed in the internal organs examined, except in the kidney, blood, and liver.

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The difference between bromovalerylurea and bromodiethylacetylurea in their reaction with alkaline solutions was investigated. 5-Isopropylhydantoin and 2-ethyl-cis-crotonylurea were easily obtained, respectively, from bromovalerylurea and bromodiethylacetylurea when refluxed with ammonium hydroxide. On the other hand, α, β-unsaturated ureides were produced from both ureides when refluxed with basic organic solvents. Bromine-substituted morpholine or piperidine was also produced as a by-product and detected by mass spectrometry. Bromodiethylacetylurea in a considerably concentrated aqueous solution converted into 2-ethyl-trans-crotonylurea, although the cis form was the main product in a diluted solution. Bromovalerylurea was scarcely changed by refluxing in water. Formation of a geometrical isomer was based on the cis-trans transition which should be caused by hydrobromic acid derived from the hydrolysis of bromodiethylacetylurea. The rate of the transition depended on the concentration of the acid and the reaction time.

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Periodical or temporary change of chlorine content is often observed in the thermal spring in coastal area. This change is generally classified into two types ; one is the periodical change closely related with tide and the other is a continuous change due to the intrusion of sea water caused by the overlifting of thermal water. Asamushi spa is in the coast of Aomori Bay, north end of Honshu island. At present, about 130 thermal springs and wells are distributed along the coast at the mouth of Asamushi River. These springs are chemically "sulfate springs" and had low salinity about eight years ago. Total amount of lifting had increased from 2000 tons/day in 1963 to 3000 tons/day in 1967, and then the content of chlorine ion increased. This increase in the content of chlorine ion was due to the intrusion of sea water caused by the lowering of thermal water pressure as a result of overlifting of thermal water. After August 1967, the total amount of lifting has been limited to below 1440 tons/day, the content of chlorine ion has decreased, and the intrusion of sea water has been reduced.

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Intrusion of sea water into thermal water was generally observed in thermal springs in coastal area at Asamushi Spa. It has been known that the chemical composition of sea water changes considerably in the process of the intrusion. Behavior of some components such as sodium, potassium, calcium, and magnesium ions, in the process of the intrusion is discussed by the analysis of the mixing ratio of sea water into thermal water. 1. The mixing ratios of eight thermal springs of high salinity are approximately calculated by the following equation, provided that a thermal water of high salinity is a mixture of sea water and original thermal water. [numerical formula] where S is the content of Na, K, Ca, Mg, Cl, SO₄, or HCO₃, in sea water, H, the content of above components in original thermal water, and A, the values of chemical analyses of thermal water. 2. The mixing ratio of sea water shows various values according to components in one spring water. This is the reason why the behavior of each component is different in the process of the intrusion of sea water. The ratio calculated from Ca is the highest, and the ratio from K or HCO₃ the lowest, and the order of the ratios is generally Ca>Cl>Na>Mg>K. 3. It is assumed that sodium, potassium, and magnesium ions in sea water decrease by the absorption on the minerals by passing through the aquiferous strata, and calcium ion increases by the ion-exchange effect caused by the absorption of sodium, potassium, and magnesium ions.

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The present series of work was undertaken to prove that there is no possibility for the presence of either ferulic acid or p-hydroxycinnamic acid in purified city water supplied by authorized water works. Both ferulic and p-hydroxycinnamic acids consume chlorine and are rapidly decomposed. They consume about 4 moles of hypochlorite for each mole of the substance, and the reaction is completed when the residual chlorine detected in the reaction mixture becomes about 0.1 ppm or less. This test for ferulic and p-hydroxycinnamic acids was carried out because some investigators attributed the incidence of a chronic bone disease, the so-called Kaschin-Beck disease, to city water, even if supplied by qualified water works, because of the presence of p-hydroxycinnamic (p-cumaric) and 4-hydroxy-3-methoxycinnamic (ferulic) acids, which were reported to have been detected in polluted river water used as a source of city water and which were found to produce changes in the cells of artilage tissue and salivary grands in young rats.

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A method is described for the separation and identification of fluorescein and four brominated derivatives on polyamide layers. The best separation was carried out by development with a solvent system composed of methanol-ammonia-water (10 : 2 : 88) and Rf values obtained thereby decreased as bromine number of the components increased. By the method subsidiary colors in commercial dibromofluoresceins were identified successfully, and furthermore determined by fluorometry after extraction from the layers.

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