A review of N-nitroso compounds which might be formed secondarily in various foods, with references to past literature on the carcinogenicity and mutagenicity of the N-nitroso compounds. Special references are made to recent literature on N-nitroso compounds detected in daily food, distribution of nitrogenous compounds and nitrites which are considered to be precursors, inhibitive and accelerative factors of N-nitrosation reaction, nitrosation of pharmaceuticals and agricultural chemicals, carcinogenicity of N-nitroso compounds, and correlation between food and human cancer.

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A new technique for measuring the rate and degree of ultimate biodegradation (biodegradation to CO₂, H₂O, and inorganic compounds) of anionic surfactants in water was investigated. Test solution (1700 ml) was incubated in a 3200 ml reaction vessel sealed with a rubber stopper at 27°under aerobic condition. A given anionic surfactant was biodegraded to CO₂ ; this CO₂ was divided according to Henry's law between the liquid phase and the gas phase in the reaction vessel with a constant proportionality. If the CO₂ content in either the gas phase or liquid phase is determined, it is possible to calculate the total CO₂ content by using a constant propotionality. Therefore, the CO₂ content in the gas phase was determined by gas chromatography and the percentage of theoretical CO₂ production was calculated. In the second step of this study, a new biodegradation index for estimating the ultimate biodegradability of anionic surfactants was studied. This index was calculated from the equation, Biodegradation index=B/A, where A indicates the theoretical CO₂ production of glucose (in %) and B that of an anionic surfactant. If the anionic surfactant is as readily biodegradated as glucose, the theoretical CO₂ production will be the same for the two and the index is a unity. An index will be below 1.0 when the surfactant is less readily biodegradated than glucose. Thus, biodegradation index will be useful not only in the estimation of the ultimate biodegradability of an anionic surfactant but also in the comparison of different anionic surfactants in terms of ultimate biodegradability.

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A derivation method for the specific and sensitive analysis of 3, 5-di-tert-butyl-4-hydroxytoluene (BHT) by gas chromatography has been developed. BHT was treated with ethanolic hydrochloric acid at 95°for 1 hr. The resulting 2-tert-butyl-p-cresol was extracted with benzene and further treated with 2, 4-dinitrofluorobenzene and sodium hydride at 95°for 1 hr to form the electron-capturing ether derivative (DNPE). The reaction was successfully applied to the gas chromatographic determination of a micro-amount of BHT in the range of 0.05-10 μg.

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In order to assess the body burden of 3, 5-di-tert-butyl-4-hydroxytoluene (BHT), human adipose tissues collected from 18 Japanese subjects during surgical treatment were analysed. The samples were extracted with hexane, the extracts were purified by Florisil column chromatography, and submitted to gas chromatographic determination via the derivation procedure. The recovery of BHT from human lipid was 66% at the level of 1 μg. BHT in the samples was confirmed by results of gas chromatography, thin-layer chromatography, and gas chromatography-mass spectrometry. BHT was found in all the samples analysed, with a maximum of 0.18 ppm and a mean of 0.10 ppm on fat basis.

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The decreased human serum cholinestrase activity inhibited by methyl- or ethyl-parathion was not recovered, but that of true cholinestrase was recovered by reaction with cysteine in vitro.

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l-Ephedrine (I) and d-pseudoephedrine (II) in a mixture of sympathomimetic amines were determined simultaneously by gas chromatography of their trifluoroacetyl derivatives (I-TFA and II-TFA). Resolution of these derivatives was carried out by the gas chromatograph equipped with a hydrogen flame ionization detector in a glass column (1m×3 mm), packed with 1% SE-30 on Gas-chrom Z, at 80°, with N₂ at the flow rate of 70 ml/min. This method is well suited not only for the simultaneous determination of I and II but also for the screening test of sympathomimetic amines (phenylmethylaminopropane, phenylaminopropane, and methylephedrine). Based on the results of nuclear magnetic resonance, infrared, and mass spectra, N, O-ditrifluoroacetyl-l-ephedrine was assigned for I-TFA and N, O-ditrifluoroacetyl-d-pseudoephedrine for II-TFA.

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After oral administration of noscapine (80-150 mg/kg) to male rabbits, detection of its urinary metabolites was carried out. The first 24-hr urine was extracted with CHCl₃ at pH 8-9 (F-I) and the remaining urine was re-extracted with CHCl₈ after acid hydrolysis (F-II). By means of thin-layer chromatography (TLC) coupled with methane chemical ionization mass spectrometry, the Dragendorffpositive spots in CHCl₃ extracts were easily recognized as the metabolites. These spots were separated by two successive preparative TLC using the solvent systems of CHCl₃-acetone (4 : 1) and cyclohexaneethyl acetate (2 : 3). The quasi-molecular ions of the separated metabolites suggested that these metabolites should be demethylation products. Thus, unchanged noscapine (M-1) and two O-monodemethylated metabolites (M-2 and M-3) were detected as free metabolites, and M-2, M-3, and M-4 (O-didemethylated metabolite) as conjugated metabolites. The main urinary metabolite was M-2, but it was excreted only in a small amount, same as unchanged noscapine.

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In the continuous determination of chloride ion in a large number of sample solutions, concentrations of which varied as in river and sea water, it was confirmed that the ion-selective electrode method was much better than the conventional Mohr's method in the simplification of the procedure, because the calibration curve of the former method was almost linear in such a wide range of chloride ion concentrations as 10-100000 ppm. The ion-selective electrode method was interfered by a sulfide ion, which, however, could be eliminated by the addition of lead acetate solution. With this method, determination of 100 ppm chloride ion solution was not affected by cupric ion less than 10 ppm and mercuric ion less than 0.1 ppm.

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Gas chromatography with alkali flame ionization detector (AFID) was applied to the determination of Cinnarizine in plasma. By using AFID, the response of Cinnarizine was about 50-fold greater than that obtained with the hydrogen flame ionization detector (FID). The detection limit of this method was 0.1 ng and the determination limit was 2 ng/ml plasma. The recovery of Cinnarizine in plasma was 104.1±3.4% (n=12). The plasma level in rabbits reached the maximum 1 to 2 hr and biological half-life was 3.8 to 4.6 hr after administration of Cinnarizine capsule formulations. Difference among the pharmaceutical preparations was recognized in the in vitro and in vivo results and it was observed that the dissolution ratio was correlated with the plasma level of Cinnarizine after its oral administration.

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Concentration of mercury and zinc in 154 human hair samples collected from almost all districts in Japan was determined by neutron activation analysis. For mercury in hair of the Japanese, the mean value of 6.0 ppm was reported in 1966, and the use of mercuric pesticides was generally prohibited after 1967. Compared with the above value, the mean value of 6.4 ppm does not markedly reflect the influence of reduction of mercury residue in rice. Dentist's hair, which showed high values of mercury in the neutron activation analysis, was examined by colorimetry using dithizone. Although the mean value of mercury in 51 samples was 11.3 ppm, about two times higher compared with 6.4 ppm, the relation of mercury concentration to the age or length of handing of mercury was not clear. For zinc in hair, the mean value of 365 ppm was reported. Difference in concentration between male and female hair was large. Zinc in hair of 6 Kabuki actors was determined by colorimetry using Zincon. Because of the large concentration of 560 ppm compared with < 200 ppm of the mean values in their generation, effect of cosmetics on the zinc content in hair was great.

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Some changes of serum lipid in mice were observed by the intraperitoneal injection of endotoxin extracted from Vibrio parahaemolyticus. A remarkable increase in the serum triglyceride content was shown in the poisoned mice after 12-24 hr. FFA level in the control mice gradually increased in response to the fasting periods for 12-24 hr whereas the level of FFA in the endotoxin-posioned mice was lower than that in the control mice. Total cholesterol, however, did not show an appreciable difference in the level of the control animals. The hepatic triglyceride content in the poisoned mice increased at 14 hr postintoxication, and the lysosomal triglyceride lipase activity slightly increased 3 hr after intoxication, and declined after 14 hr. There was not very much change of the triglyceride level in the serum in cortisone plus endotoxininjected mice. An increase of serum triglyceride in CCl₄-poisoned mice was not observed at 14 hr postinjection of endotoxin in spite of its high level in the serum of endotoxin-injected mice. The mechanism responsible for the development of the hypertriglyceridemia in mice after injection of endotoxin is unkown at present.

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Cadmium is quantitatively extracted from an aqueous solution by shaking with thiothenoyltrifluoroacetone (STTA) solution in xylene in the presence of 1, 10-phenanthroline (PHEN) at pH 5.6-10.0. The excess STTA in organic phase is removed by shaking with borax-NaOH buffer solution (pH 11.5). The cadmium complex extracted is stable and has an absorption maximum at 370 nm. The calibration curve follows Beer's law over the range of 1-35 μg of cadmium in 10 ml of the organic phase. The molar absorptivity at 370 nm is 3.43×10⁴ and the sensitivity is 0.0032 μg Cd/cm² for the absorbance of 0.001. The coefficient of variation of the absorbance for 5, 20, and 30 μg of cadmium was 0.8, 0.4, and 0.3%, respectively. The molar ratio of cadmium, STTA, and PHEN in the extracted species is estimated to be 1 : 2 : 1 by the continuous variation method. Mercury (II), copper (II), zinc (II), cobalt (II), manganese (II), and sulfide interfere with the determination even when their amount is 1/10 of cadmium. However, the permissible amount of these interfering ions except manganese (II) and sulfide can be increased by the addition of potassium cyanide. The method proposed is sensitive, and good results were obtained for recovery tests of cadmium on artificial sea water. The sensitivity of this method is better than that reported by Solanke, et al. using STTA.

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Determination of Sulfides in sediments is an important indicator for the extent of water pollution, but usual determination method is insufficient in accuracy because of the lability of sulfides. As the error in determination may occur in pretreatment, sulfides have to be stabilized immediately after samples are taken from sediments. Samples were kept stable for 5 days by using hexaamminezinc solution as the pretreatment solution and storing below 5°. The proposed method was satisfactorily applied to the determination of sulfides in sediments, since the recovery and standard deviation of sulfides (in sediments) was 100.1% and 100±8.28%, respectively.

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Leucine reacted with nitrite ion in a phosphate buffer solution without heating to form a cyanide ion by irradiation with a xenon lamp. Addition of mercuric ion to this solution resulted in increased formation of the cyanide ion.

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The protein and deoxyribonucleic acid (DNA) concentrations, and acid deoxyribonulease activity of femur were examined in rats intraperitoneally administered cadmium acetate, lead acetate, zinc acetate, or combined metals (0.89 μmol as a metal ion/100g body weight) 5 times at 2-day intervals. The bone protein concentration after the injection of cadmium, zinc, and combined metals significantly decreased in the diaphysis of femur compared with that of normal rats, but the protein concentration in the epiphysis was significantly increased by zinc alone. The DNA concentration in the epiphysis significantly increased by the administration of any of the metals, while it was significantly increased in the diaphysis by zinc alone. On the other hand, the acid deoxyribonuclease activity in the diaphysis was not altered significantly by any of the metals, but this enzyme activity was significantly reduced in the epiphysis by zinc alone. The present results suggest that the effect of zinc on bone metabolism differs from that of cadmium and lead.

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A simple method was developed for the determination of vinyl chloride monomer by using head space analysis. This method can detect as little as 0.1 ppb of vinyl chloride monomer in water. By the water elution test for 72 hr at room temperature, 106±8.8 μg/m² of the monomer was detected from poly vinyl chloride (PVC) pipe (containing 8.9 ppm of the monomer) in spite of various sizes of surface area, and this value was only ca. 1% of total vinyl chloride monomer. Among 106 samples of drinking water which were not used so frequently such as faucet of a public garden, vinyl chloride monomer was detected from 28 samples and their average was 1.8±9.8 ppb. Vinyl chloride monomer was not detected from the drinking water samples in ordinary use. This technique can be applied to the quantitative analysis of the monomer in PVC products.

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