As a practical application of mass spectrometry in forensic chemistry, mass spectra of eleven kinds of barbiturates including their metabolites were measured. Initial fragmentation of the barbiturates was classified into two large patterns : (a) elimination of the 5'-substituent as an olefin molecule (barbital, phenobarbital, amobarbital, etc.), and (b) elimination of the 5'-substituent as a radical (ethylhexabital, methylhexabital, allobarbital, etc.). Identification of ethylhexabital and its metabolites extracted from urine after administration of ethylhexabital was successfully made by the combination of thin-layer chromatography and mass spectrometry.

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The inhibitive effect of xanthene dyes on tryptic activity was examined, using erythrosin, phloxine, and Rose Bengal, photodecomposed in various ratio by irradiation of ultraviolet ray in phosphate buffer at pH 7.6. Experimental results showed that the degree of inhibition was almost constant for a range of decomposition of these compounds from 0 to 70%. Purplish products (PP-1 and RP-1) were separated from the photodecomposed phloxine and Rose Bengal solutions on a cellulose column by elution with 0.1 N sodium hydroxide. Both PP-1 and RP-1 were confirmed to inhibit the tryptic activity.

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A trace amount of cadmium of ppb level was determined by aspirating the methyl isobutyl ketone extract using ammonium pyrrolidine dithiocarbamate as a chelating agent. When a large aqueous phase/solvent ratio was used, the volume of the organic phase obtained after extraction decreased to a smaller volume compared with the initial volume added because of the appreciable solubility of methyl isobutyl ketone in water. In addition to the solvent effect, this "solubility effect"resulted in much enhanced sensitivity for the determination of cadmium.

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The present experiment was undertaken to apply the previously established method to biological samples. Interference of organic materials on the color reaction could be eliminated by burning the ether extract with potassium carbonate in a crucible. Standard method A was as follows : The ether extract of a biological sample, acidified with sulfuric acid, is warmed with 1 ml of 15% potassium carbonate solution and a few milliliter of distilled water in a porcelain crucible (3.4 cmφ, 4.5 cmh) and heated on a boiling water bath to dryness. The organic material is completely carbonized by heating the crucible over an open flame. The residual ash is washed into a 20 ml conical flask through a filter paper, using a small volume of distilled water. This aqueous filtrate is evaporated to dryness and the residue is added with 1 ml of acetic acid, 1 ml of 2', 7'-dichlorofluorescein solution (250 mg/liter acetic acid), and 3 drops of 30% hydrogen peroxide. The flask is sealed with a parafilm and the solution is warmed at 45°for 70 min, shaking for a few seconds every 20 min. After addition of 3 ml of pyridine to this solution, its absorption is determined by spectrophotometer at 530 mμ. As a more simplified method B, all the reactions can be carried out in the same crucible but the final solution must be filtered through a filter paper to remove the carbon. Recovery test of bromvalerylurea in the urine extract by methods A and B showed that the values were not greatly different between these two methods.

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A two-step method was established for the separatory determination of nitrate-nitrogen and nitrite-nitrogen in waste or polluted water. In the first step, organic nitrogen and ammonia-nitrogen, which are liable to be decomposed in alkaline state, are removed by distillation, and the nitrate-nitrogen and nitrite-nitrogen are reduced by the Devarda alloy. In the second step, the same procedure is carried out after preliminary decomposition of the nitrite-nitrogen with sulfamic acid and the amount of nitrate-nitrogen is determined. This method was found to be practicable.

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As one of fundamental experimental conditions in the activation analysis of human hair, examination was made on changes in the concentration of trace elments by washing hair samples. External contamination of hair samples was easily removed by washing with organic solvents but some amount manganese and sodium was washed out by this treatment. Easily water-soluble elements were removed by washing with a detergent or deionized water. Use of city water instead of deionized water resulted in absorption of zinc into hair samples. Washing of hair samples with organic solvents was adopted for examination of trace elments in human hair, because the washing procedure is easy, washing experiments can be repeated with minimum of error, and easily water-soluble components are useful for individualization of human hair.

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Hair samples were analysed by the short time irradiation with neutrons using pneumatic tube for the purpose of increasing detectable elements and establishing a rapid method of analysis in a practical case. Spectra of short-life nuclides of hair samples from different donors were sufficiently characteristic and distinguished from each other. Main detectable elements were Al, Br, Cl, Mn, and Na, and sometimes I, Se, Ti, and Zn were detected. Determination of Al and Cl was possible by a short irradiation. Their complex spectra could be analysed by the stripping method. As polyethylene sheet contains a markedly large quantity of Ar and other elements which disturb the determination of components in samples, its use in the non-destructive activation analysis must be reconsidered.

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The dithizone method for determination of mercury in JIS K 0 102 (Testing Methods for Industrial Waste Water) was improved for the determination of total mercury in sludge. In the improved method, the sludge was decomposed in HNO₃-KMnO₄ medium using an apparatus described in the Standard Methods for Hygienic Chemists in place of the JIS decomposition bottle. Recovery of mercury from the sludge added with C₂H₅HgCl was 91.2%, and was almost quantitative. Application of this method for the determinations of total mercury in sludges obtained in sea at Ichihara Industrial Area in Chiba Prefecture was proved to be fairly satisfactory. The average recovery of mercury from these sludges was 99.6%, and the deviation was within 10%.

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Hair samples were first collected every other day, then once a week, and finally once a month until three months from three individuals and were analysed by neutron activation. Variation in the concentration of trace elements in the hair samples with lapse of time was generally insignificant and smaller than the difference among individuals. The γ-ray spectra from the same person showed analogous patterns which were characteristic to the individual. Concentration of trace elements in the hair from the same head maintained a constant level which seemed to be peculiar to the head hair. With one exception to the above mentioned trends was a marked variation in the concentration of bromine in one person. This change was due to hair dressing and it was considered that a large quantity of bromine was absorbed in the form of bromate from the permanent waving agent. Increased bromine concentration decreased gradually and was reduced to the usual level after two months.

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Following radiochemical analysis of microamount of mercury in hot spring water in 45 places in Beppu spa, mercury content in dried sludge and solution was determined by radiochemical analysis with Kon-ya sulfur sludge which was found to have the effect of accelerating urinary excretion of mercury during hot spa treatment of alkylmercury toxicosis. The content of mercury in the sulfur sludge was 15.4 ppm in dried sludge and more than 14.6 μg/liter of mercury is in liquated state in the natural hydrated sludge (liquation rate, 9.5%). This result indicates that the mercury present is much greater than that in other soils or in spa water.

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In order to elucidate the action mechanism of sulfur sludge bath, which showed a specific effect in accelerating urinary excretion of mercury during spa treatment for alkylmercury toxicosis, methyl methylmercuric sulfide isolated from a poisonous shellfish caught in Minamata Bay, was labeled with ²⁰³Hg, and this Me-Me²⁰³HgS and ²⁰³Hg acetate were administered to mice. Effect of hot spring bath on the biological distribution of these labeled mercury compounds was examined. Both labeled mercury compounds showed a marked accumulation in the kidneys after their intraperitoneal administration. Systemic distribution of the sulfide was much more gradual and more homogeneous than that of the acetate. Disappearance of the acetate and sulfide from the organs after their intraperitoneal administration was found to be accelerated by continued bathing in sulfur sludge for 3 weeks but this action appeared more slowly in the sulfide. This accelerative effect was not significant when the bathing was in simple spa water. When the bathing was made in water containing ²⁰³Hg, the amount of mercury in various organs increased with time up to 6 th day but the increase became insignificant thereafter. The amount of mercury in the animals given simple spa baths was twice that in the animals given sulfur sludge baths. When the mice given Me-Me²⁰³HgS were bathed in sulfur sludge labeled with ¹⁹⁷Hg acetate, decrease of ²⁰³Hg from the liver was much faster than that from the kidneys and that the accumulation of ¹⁹⁷Hg was extremely small, as found by concurrent measurement of ¹⁹⁷Hg and ²⁰³Hg in the liver and kidneys by a 400-channel pulseheight analyzer. These results prove that the large amount of mercury excreted into the urine of patients of alkylmercury toxicosis by continued bathing in sulfur sludge is the mercury already accumulated in the body and not due to turnover of mercury in the sulfur sludge.

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A new detergent method using Babcock's test bottle for estimating fat content in milk products was investigated. The volume each component in the detergent reagent, consisting of Tween 80, sodium salicylate, and amyl alcohol, to be added to milk and ice cream was determined, the fat content obtained being compared with those obtained by the detergent method already reported and Rose-Gottlieb's method. The fat content in milk products estimated by this method was the same as that obtained by the Rose-Gottlieb's method.

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