A rapid and accurate method for determining nitrogen oxides in exhaust gases has been developed. The nitrogen oxides (NO_x) in a sample were oxidized by ozone and absorbed into a weak acidic solution to be converted to nitrate. The determination of NO_x was performed by measuring the absorbance of the solution at one wavelength ranging from 215 nm to 230 nm where nitrate absorbed strongly and the absorption was little affected by coexistent gases in the sample. Only 5 min was required for one determination. The method can be used for the determination of (2×10^-62×10^-4) M nitrate converted from NO_x with an error of ±2.4 %. The lower determination limit was apporoximately 1 ppm by using a 1l sample gas container with the absorption solution of 20 ml. Though the molar absorptivity, 6400 at 215 nm, was smaller than those by other chemical methods for NO_x determination, the useful determination range was little defferent compared with the other methods because the present method required neither pretreatment nor preparation for chromophores. High concentration of hydrocarbons and organic gases caused positive errors for the analytical result. However, unless the sample contains more than 500 ppm of those gases, NO_x can be measured without correction. The analytical data of NO_x in flue and automobile exhaust gases were in fair agreement with those obtained by Zn-reduction NEDA method.

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A coated wire electrode (CWE) for nitrate was constructed by the use of polyvinyl chloride (PVC) or epoxy resin as a polymer membrane. The CWE consists of a copper wire and the polymer matrix incorporating a liquid ion exchanger which coated on the whole surface of the wire. The characteristics of the CWE were dependent on the thickness of the polymer membrane and polymer matrix composition. The appropriate thickness of the membrane was about (0.050.2) mm. The most appropriate mixing ratios of the polymer to ion exchanger in the membrane were 1/l and 2/l for the CWE using PVC (PVC-CWE) and CWE using epoxy resin (Epoxy-CWE), respectively. The responses were Nernstian for both CWEs with this thickness in these compositions. The CWEs respond in a few seconds with the stability of within ±2.0 mV. The reproducibility and durability for the Epoxy-CWE were good and the linear response limit was 2 × 10^-5 M nitrate, whereas the durability of the PVC-CWE was poor and the limit was at most 1 × 10^-4M. In addition, the selectivity of the Epoxy-CWE was improved for the anions such as I^- or ClO₄^- which causes large interference in a usual barrel type of liquid membrane electrode.

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The a.a.s. method for the determination of trace magnesium in iron matrices requires a preliminary separation of iron. As a separation method of iron(III) hydroxide has been proposed, because it is more rapid and convenient than filtration and centrifugation. It is found that magnesium ion does not coprecipitate with iron (III) hydroxide in the pH range from 5.0 to 7.5 and remains entirely in the mother liquour, while aluminum ion which causes serious errors for the determination of magnesium, co-precipitates with iron (III) hydroxide perfectively in this condition. Therefore, this flotation method is available not only for the removal of iron matrices but also for the exclusion of an interfering component like as aluminum ion. This method was applied for the determination of magnesium contents in natural samples such as iron ore, bauxite and cement. The procedure is as followed; Place a 10 ml aliquot of acidic sample solution containing up to 100 μg of magnesium in a 50 ml beaker, and add 1 ml of ethanol. When samples are prepared from bauxite or cement, a proper amount of iron (III) is introduced by adding (13) ml of 0.1 M ammonium iron (III) sulfate solution. Adjust the pH to 6 ± 0.5 with aqueous ammonia to precipitate iron (III) hydroxide. Transfer the contents of the beaker completely to a flotation cell, and add 1 ml of 0.1% sodium oleate. By bubbling the sample solution with air from the lower end of the cell, agitate the iron (III) hydroxide to float up. Filter with suction and wash the precipitate by spraying water. The filtrate and washings are combined into a 50 ml of volumetric flask and dilute to the mark with water. Magnesium concentration in the solution was determined by a.a.s. The standard addition was always carried out to exclude interferences from alkali and ammonium salts.

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An X-ray diffractometric method is applied to determine zinc oxide with low crystallinity in zinc powder. Zinc oxide prepared by thermal decomposition of zinc oxalate exhibited more approximate attice distortion (β cot θ) of the zinc oxide in samples than pulverized one due to lower crystallinity. Therefore, thermally decomposed zinc oxide was employed as a standard material. To reduce errors due to the difference in crystallinity between the standard material and samples, the synthesized zinc oxide was heated to such an extent that its half-width of 002 reflection line was equal to that of zinc oxide contained in samples. The standard mixture for calibration was prepared as follows: a known quantity of the standard zinc oxide {(110)%} was added to an aliquot of the sample, and they were mixed by hand in an agate mortar. A straight line was obtained over the range of (110) % additives by measuring the 002 reflection line intensity of zinc oxide. The present standard addition method was applied to the determination of zinc oxide of (1.95.9)% in zinc powder. The determination limit was 0.27 %, and 5.8 % of the coefficient of variation was obtained by ten measurements at a level of 3.9% zinc oxide content.

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A stable additive compound, H₂SiF₆-3DMF, was obtained as a white crystalline solid by the reaction of hexafluorosilicic acid and N, N-dimethylformamide (DMF), and used as a standard substance of the conductimetric titration of alkaline earth metals and aluminum in DMF solution. The inflection points between H₂SiF₆ and each metal ions were observed at the mole ratios of 4:1, 2:1, and 1:1. These combination ratios were not influenced by The presence of either water within 1 percent or inorganic acids. The method was applied to the determination of alkaline earth metals (Be, Mg, Ca, Sr, Ba), aluminum, and their mixtures (Be-Ca and Be-Al).

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The yellow complexes of platinum (II, IV) or palladium (II) with potassium alkylxanthates (KR X) such as ethylxanthate (KEtX), propylxanthate (KPrX), butylxanthate (KBtX) and pentylxanthate (KPeX), can be extracted into methyl isobutyl ketone (MIBK). With this solvent extraction method, atomic absorption spectrophotometry (aas) of foregoing metal ions was investigated about the extracting conditions, the interference of co-existing ions and the precison of the determination. The recommended procedure is as follows: To a sample solution (containing up to 400 μg of platinum or up to 40 μg of palladium) is added 10 ml of 10 % ammonium tartrate buffer solution for platinum or 10 % ammonium acetate buffer solution for palladium, respectively. The pH value of aqueous phase is adjusted to around neutrality, and then 10 ml of a 5 % solution of KRX is added. The xanthate complexes are extracted with 10.0 ml of MIBK by shaking for 3 min, and the extract is directly subjected to aas at 265.9 nm for platinum and 244.8 nm for palladium. The limits of determination are 0.68 ppm for platinum and 0.06 ppm for palladium in MIBK per 1 % absorbance, respectively, by aas in air-acetylene flame controled to be fuel lean. The optimum pH regions of extraction are from 5.0 to 10.0 for platinum (II) -xanthate, from 5.0 to 7.5 for platinum (IV) -xanthate and from 6.0 to 11.0 for palladium (II) -xanthate. The coefficient of variation of this method after each 10 runs, ranged from 0.67 % to 2.82 % for 100 μg to 300 μg of platinum and from 0.40 % to 1.21 % for 10 μg to 30 μg of palladium.

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Trace amounts of sodum alkylbenzenesulfonate (LAS) in river waters and sediments were determined by high-performance liquid chromatography (HPLC). The dried sediments were refluxed and extracted with methanol-benzeme mixture. After the concentration of the extract the residue was dissolved in hot water, and methylene blue active substances (MBAS) was extracted with 1, 2-dichloroethane using methylene blue colorimetry. Before MBAS was extracted with 1, 2-dichloroethane, some interfering substances were removed by pre-extraction with carbon tetrachloride. LAS in 1, 2-dichloroethane extract was determined by HPLC. LAS in river waters was determined in the similar way. Stationary phase of Shimadzugel PSG-100 and Shimadzu PCH-05 were compared, and it was found that PCH-05 has the following advantages over PSG-100: (i) In river waters and sediments the peaks of LAS were well separated from those of MBAS other than LAS. (ii) Homologous series of LAS with C₁₀C₁₄ alkyl groups were resolved according to the alkyl chain length. (iii) The positionary isomers of phenyl group of LAS were not separated. The method employing PCH-05 was applied to the determination and distribution of homologous series of LAS in river waters and sediment. Recommended conditions for HPLC were as follows: column, PCH-05 (Shimadzu), 4 mm i.d. × 250 mm; mobile phase, 0.08 % (w/v) disodium hydrogenphosphate in 50% ethanol; flow rate, 0.3 ml/min; column temperature, ambient; detector, UV 225 nm. The calibration curve for sodium dodecylbenzenesulfonate was linear within a range of (0.010.3) μg/5 μl (injection volume). The recoveries of known samples were (9199) %.

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In a fluorescence X-ray analysis of Ag-Cu thin film alloys on Al, Ni, and Ta metal substrates, an excitation effect due to the scattered X-ray from the substrate was observed. The Cu K_α intensity is strongly enhanced with the Al substrate when compared with the Ta one, while the Ag K_α intensity is not so much affected by the kind of the substrate. The substrate effect was evaluated by simulating the X-ray scattering process within the thin film specimen and the substrate by using the Monte Cairo technique. The theoretical correction including the matrix effect within the thin film was then applied to the simultaneous determination of its composition and thickness. The analytical results by the proposed method for the Ag-Cu thin film alloys (Ag:Cu=72:28) formed on the Al substrate with the thickness of 170 nm and 320 nm were Ag-Cu=68:32 with the thickness of 150nm and Ag:Cu=70:30 with the thickness of 310 nm, respectively. By applying the theoretical correction, the proposed fluorescent X-ray spectrometric method allows one to use a bulk specimen as a reference as well as the thin film and is effective for a nondestructive analysis of thin film specimens on substrates.

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Determination of trace amounts of formaldehyde was investigated. Formaldehyde reacted with ethyl acetoacetate and ammonia to give 3, 5-dicarbethoxy-1, 4-dihydrolutidine. The solution diluted of its compound was appeared strongly fluorescence in the blue, thus enabling the fluorometric determination of formaldehyde. But other aliphatic aldehydes obtained lutidine derivatives by the similar manner as above, which were given to correspondent fluorescence. Therefore in the presence of other aliphatic aldehydes, for determination of trace amounts of formaldehyde, it was necessary to separate their ccmpounds. The separation of lutidine derivatives was completely achieved on a column packed with Hitachi gel #3011 (4.0 mm i.d., 25 cm length) by methanol containing 20%-water eluent. Consequently, trace amounts of formaldehyde could be fluorometric determined by high performance liquid chromatography even in the presence of other aliphatic aldehydes. In this paper, this method was applied to the determination of formaldehyde in cigarette smoke. As a result of this method, about 20×10^-6 g of formaldehyde were found in cigarette smoke.

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A novel technique for a determination of trimethylamine (TMA) at a few ppb levels in ambient air has been investigated. TMA preconcentrated on TENAX-GC adsorbent from sample gas was injected into a gas chromatograph with thermal desorption at 200°C. Gas chromatographic separation was performed by the column packed with 5 % squalane and 2 % KOH on Chromosorb 104 {(80100) mesh} at 130°C. The eluent from the column was converted to nitrogen oxide by combusion and detected with a chemiluminescent nitrogen detector. There is no interference from other hydrocarbons, which is normally a serious problem in FID-GC. A collection on and a recovery from TENAX-GC adsorbent for TMA were nearly quantitative. The optimal conditions for TMA collection were established with respect to sampling rate, sample volume, adsorbent temperature and others. As an application of this technique, the air in a freezer storing organic compounds such as amines, sulfur compounds and hydrocarbons was analysed, and a concentration of 2.4 ppb for TMA was obtained by sampling 6l of the air. This is comparable to the results of 5.8 ppb and 1.3 ppb with 15 l' sampling by conventional method.

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In the presence of ferric chloride, carbazole reacts with 3-methyl-2-benzothiazolinone hydrazone (MBTH) to form a colored product in methanol-water medium, and the product can be effectively extracted with chloroform. The reagent blank was influenced by the concentration of ferric chloride. In order to stabilize the reagent blank, it was necessary to stand after addition of HCl-CH₃OH mixture, and also after extraction. To 5 ml of methanol solution of the sample, 5 ml of 1 % solution of ferric chloride in 0.8 M hydrochloric acid and 5 ml of 0.4 % aqueous solution of MBTH were added. The solution was allowed to stand for 45 min at room temperature and diluted to 25 ml with a mixture of concentrated hydrochloric acid and methanol (1:1). After standing for 20 min, the colored product was extracted with 5 ml of chloroform. After complete separation of the two phases, the chloroform phase was stood for 20 min. Then, the absorbance of the chloroform extract was measured at 625 nm against the reagent blank. The calibration curve was linear in the range of 0.5 μg to 10 of carbazole.

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A method was developed for the determination of trace mercury in sulfur or pyrite by atomic absorption spectrometry. Atomization of mercury as well as its separation from sample matrics was performed by electric heating. In order to avoid vaporization of sulfur or/and pyrite, the sample was covered with silver powder which was most effective of metal powders and oxides examined. The analytical procedure is as follows: About 0.1 g of sample is weighed in a silica boat, covered with (1.52.5) g of electro-deposited silver powder, and heated at about 400°C. The mercury vapor generated is introduced into a cold trap with argon carrier gas. The amalgamated mercury thus obtained is then released by heating the gold trap at 700 °C and the absorbance based on mercury is measured at 253.7 nm. The analytical results for (1.02.5) ppm mercury in sulfur and pyrite samples were in good agreement with those obtained by the atomic absorption spectrometry after reduction of mercury (II) in the sample solution by tin(II) chloride.

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Beryllium containing the large amount of diverse ions was determined with Chromazurol S (CAS) and Triton X-100 in the presence of sodium perchlorate after the separation as acetylacetonate. Beryllium was separated by its extraction as acetylacetonate in the presence of EDTA at pH 7 into benzene and back-extraction in 3 M hydrochloric acid for three times. After the addition of a few drops of perchloric acid and 5 ml of nitric acid, the aqueous phase was evaporated to almost dryness and the residue was dissolved in 3 ml of water, followed by the determination procedure. Recommended procedure is as follows. Add 2 ml of EDTA solution (0.05 M), 1.0 ml of CAS solution (0.25 %) and 2 ml of Triton X-100 solution (0.02 g ml^-1) to the sample solution. Adjust pH to 5.1 with sodium acetate solution (0.2 M). Add 6 g of sodium perchlorate, dissolve the mixture and dilute to 25.0 ml with water. Measure the absorbance at 605 nm against the reagent blank in a 10 mm and a 50 mm cell for (0.12) μg and (0.010.1) μg of beryllium, respectively. Beer's law was obeyed for (0.012) μg of beryllium in 25 ml. The molar absorptivity was 1.1 × 10⁵ dm³ mol^-1 cm^-1. Sodium perchlorate was added to remove the effect of anions such as perchlorate and acetate. Less than 3 mg of Ca(II), Mg(II), Zn(II), Cd (II), Pb(II), Cu(II), Ni(II), Fe (III), Al(III), Cr (III) and 4g of chloride, nitrate and sulfate did not interfere.

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Cesium was separated from rubidium by the chromatographic ion-exchange method with Duolite C-3. After a sample solution was lead to the resin column, rubidium and cesium were eluted with 0.35M hydrochloric acid solution and 3 M hydrochloric acid solution, respectively. The procedure was applied to the determination of radio cesium-137 in soil, total diet, vegitable, fish, and skim milk. The overall chemical recovery of cesium was 94.7 % on the average for the samples. The amount of rubidium in the final cesium fraction was decreased to less than 10^-3 part of the initial amount. The chemical procedure for ten samples took about 3 days.

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Pretreatment of trace amount of sulfate ion in aqueous solution with the barium chromate-acidic suspension method (JIS) and quantitative determination of sulfate ion by atomic absorption spectrometry were studied. The whole procedure is consisted of (i) quantitative precipitation of the sulfate ion with barium chromate-acidic suspension, (ii) filtration of the precipitate, and (iii) analysis of the liberated chromate ion by atomic absorption spectrometry. Using the synthesized solution containing Cr (VI), effects of the amount of various substances, such as NH₄OH, NH₄OH containing Ca, mixed acid, mixed solution, ethanol and some sodium compounds, on the atomic absorbance of Cr (VI) were examined. The best results were obtained under the following conditions. To a 10 ml of the sample solution, add 4 ml of the barium chromate-acidic suspension, 1 ml of the ammonium hydroxide solution containing Ca and 10 ml of ethanol. Shake for 1 min, and filter through a dried filter paper, and then, measure the atomic absorbance of the filtrate. Under the optimum condition, the recovery of sulfate ion was 92 % or better. The proposed method was compared with the spectrophotometric method (JIS) for the determination of the sulfate ion at ppm level in the sample such as the elution of colored organic and inorganic pigments. Agreement between the two methods was within the acceptable allowance when the sample solution was colorless. In general, it is difficult to use the spectrophotometric method, prescribed in JIS K 0102-1974, for the analysis of most of the colored sample solutions. But the proposed method was applicable to the colored sample solutions as well as to the colorless.

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The effective concentration of heavy metals present in ppb level in aqueous sample is performed by the extraction into diisobutyl ketone (DIBK) using ammonium pyrrolidinedithiocarbamate (APDC). DIBK is far less soluble in water compared to methyl isobutyl ketone or butyl acetate usually used in the solvent extraction-atomic absorption system and enables to concentrate trace metals up to 100 times. Various heavy metals are able to be extracted simultaneously with APDC at a wider pH range (1.5 to 6.0) than with the other chelating agents such as sodium diethyldithiocarbamate, 8-hydroxyquinoline, cupferron, and potassium butylxanthate. The results are as follows: (1) The calibration curves are linear up to 0.4μg Cd/ml(DIBK), 1.0 μg Cu/ml (DIBK), and 2.0 μg Pb, Ni, Co, Fe/ml(DIBK). (2) The coefficients of variation (%, n=10) are 2.7 for 0.5 μg Cd, 0.5 for 4.0 μg Cd; 3.0 for 2.0 μg Cu, 0.6 for 10.0 μg Cu; 6.5 for 2.0 μg Pb, 0.9 for 20.0 μg Pb; 3.5 for 2.0 μg Ni, 0.9 for 15.0 μg Ni; 3.1 for 2.0 μg Co, 0.8 for 20.0 μg Co; and 8.9 for 2.0 μg Fe, 1.2 for 15.0 μg Fe. (3) The 1 % absorbances for Cd, Cu, Pb, Ni, Co, and Fe are 0.16 ppb, 0.5 ppb, 1.2 ppb, 0.8 ppb, 0.8 ppb, and 0.8 ppb, respectively. (4) Recoveries of all these metals for the samples of river water, sea water, and effluent of treated sewage are satisfactorily good as high as 95 %.

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