Multivariate analysis was applied to the estimation of the blend composition ratio of polyethylene to polypropylene using a personal computer. Pyrograms of 19 known blend compositions (known sample) were obtained by pyrolysis GC, individually. Twenty seven peaks were selected from each pyrogram. The area of twenty six peaks were divided by each of six specific peak area and the quotients were given as relative values (18). The obtained six matrixes (19×26) were filed in a personal computer. A blend polymer with unknown composition of polyethylene and polypropylene was pyrolyzed and the resulting pyrogram was calculated to obtain relative values (18). The matrixes (20×26) of filed unknown sample data were used for the multivariate analysis such as cluster analysis, quantification IV and principal component analysis. The unknown sample was compared with 19 known samples using cluster distance, dendrogram, principal component score and determined blend composition of 1:1.

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A trace amount of lead in a piece of soda-lime glass (0.10.8 mg) was determined after atomizing at 1820°C for 30 s in a graphite-cup furnace with 20mg of graphite powder. Other sample particles of glasses were successively atomized in the same furnace. The amount of lead was determined from the peak area of the absorption signal for lead. After atomization, the matrices of glass were remained in the furnace as transparent sphere due to the incomplete reaction with the powder. With the repetition of atomization for about 15 times, it finally reacted with the powder and evaporated as aerosol which gave the large background absorption. In such a case, the newly replaced powder made it possible to atomize in the same furnace without background absorption. Borosilicate and fused silica glasses could not be atomized even at 2250°C, the maximum temperature of the furnace used. However, they could be atomized at 2250°C for 7.5 s in the furnace when the matrix of soda-lime glass was reacted with the graphite powder and evaporated as aerosol. The bacground absorption signal was automatically corrected by Zeeman-polarized atomic absorption spectrometer. Detection limits were 0.03 and 0.04 ng for lead at 1820 and 2250°C, respectively, which corresponded to 0.06 and 0.08 ppm of lead in 0.5 mg of glass samples.

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The fluorescence properties of Tb(III) and Dy(III)-EDTA complexed with salicylic acid or its derivatives (5-sulfosalicylic acid, 5-chlorosalicylic acid, 5-nitrosalicylic acid, 3, 5-dinitrosalicylic acid, 5-aminosalicylic acid and 4-aminosalicylic acid) were investigated. The variations in fluorescence intensity of the ternary complexes and ligands due to the difference in the kinds and substituted sites of the functional groups were compared. From the experimental results, it became clear that the 4-aminosalicylic acid-EDTA system had the lowerest fluorescence blank value (i.e., noise) of the ligand, and the S/N. It was an excellent fluorometric system for simultaneous determination of Tb(III) and Dy(III) with a high S/N and lower detection limit. At pH 13.2, the detection limits of Tb(III) and Dy(III) were 5.3 and 10 times lower than that of the salicylic acid-EDTA system attending 6.4 ppb and 160 ppb, respectively, with 6×10^-4 mol dm^-3 4-NH₂·Sal-2 × 10^-4 mol dm ^-3 EDTA-borax buffer solution. The fluorescence intensities of the sample solutions were measured at fixed emission wavalengths of 546 nm for Tb(III) and 577 nm for Dy(III) by excitation at the wavelength of 323 nm.Terbium in rare earth oxide was analyzed by the 4-NH₂· Sal-EDTA system. In the range of 60800 ng, Tb(III) in 0.5 mg rare earth oxides (La₂O₃, Dy₂O₃, Gd₂O₃) was successfully determined by a standard addition method. The recovery of Tb(III) was 95.8106.7% with a relative standard deviation of 2.2%.

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A method for the simultaneous determination of eptazocine and its metabolites in human plasma and urine was developed by HPLC with electrochemical detection. The chromatography was carried out on a TSKgel ODS-80TM column (6mm i.d ×15cm) using 5mM sodium heptylsulfonate in 0.07M sodium phosphate (pH 3)-methanol (65 : 35) as the mobile phase at a flow rate of 0.8ml per minute, and current-potential of the electrochemical detector was set at +1.0V (plasma) or +0.92V (urine) at the range of 10 nAFS. Sample clean-up with disposable cation exchange column (carboxylic acid form) and the use of trimetoquinol-HCl as internal standard might made this assay method as an accurate and reproducible one. This analytical method is simple, rapid and sensitive, and can be applied to determine eptazocine in plasma and urine.

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Trace amounts of silicon in pure iron were indirectly determined by spectrophotometry, based on iron(II)-ferrozine complex formation. After decomposition of pure iron sample with sulfuric acid was separated as SiF₄ from the matrix and absorbed into boric acid solution. The liberated silicon was converted to 12-molybdosilicic acid, followed by solvent extraction. The complex was decomposed with an alkaline solution, and after acidification, Mo(VI) was reduced with NaBH₄. The reduced Mo(III) was reoxidized with Fe(III) solution, and the resulting Fe(II) was determined by spectorophotometry as its ferrozine complex. These results suggest that silicon atom is associated with 12 molybdenum atoms, and consequently, with 36 iron(II) ions. This method has 30 times higher sensitivity than Molybdenum Blue method, and was successfully applied to the determination of silicon as low as 2μg/g in pure iron. The analytical results of standard samples were in good agreement with the certified values.

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A method for simultaneous microdetermination of fluorine, chlorine, bromine, iodine and sulfur in organic compounds by ion chromatography (IC) was developed. Sample solutions for IC were prepared according to an oxygen flask combustion method or to dissolution of dissociable halides and sulfate. The following procedure is employed: One to eight milligrams of organic samples were decomposed in the presence of oxygen, in a 500 ml quartz flask for fluorine determination and in a Pyrex flask for other elements. The combustion products were absorbed in 20 ml of 2 mM sodium hydroxide plus 100 μl of 5% hydrazine solution for analysis of all four halogens, and in 20 ml of 2 mM sodium hydroxide plus 100 μl of 1 % hydrogen peroxide solution for analysis of both sulfur and halogens except for iodine. The absorbed solutions were treated with a Toyo pak IC-SP cartridge, and the filtrates were injected into a chromatograph (Yokogawa Electric Works, Model IC 100) equipped with a porous polymethacrylated gel column (TSKgel IC-Anion-PW, at 40°C), a cation exchange membrane suppressor and a conductivity monitor. A 3 mM NaHCO₃-1.2 mM Na₂CO₃ solution was used as a mobile phase at a flow rate of 1.6 ml/min. Calibration curves in the peak area constructed from the sodium or potassium salts of five anions (F^-, Cl^-, Br^-, I^- and SO^2-₄) showed good linearity and high reproducibility over a wide range of concentration. The developed method was successfully applied to the simultaneous elemental micro-analysis including iodine determination. The analytical values were in good agreement with the theoretical values for each compound within an error of ±0.3%.

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Recently, contamination by trichloethylene (TCE) in groundwater from semiconductor factories has been a problem. As a coloration reaction of gem-polyhalogen compounds, the Fujiwara reaction is well known, but it has been mainly used for the determination of chloroform. The aim of this paper is to develop a sensitive reaction system for TCE and to apply it to FIA. After examining combinations of 9 derivatives and 6 bases, the combination of pyridine and tetramethylammonium hydroxide (TMA) was the most sensitive. Since the sensitivity decreased with the increase of water content in pyridine solution, TCE had to be separated from water samples into pyridine-TMA solution by means of porous poly (tetrafluoroethylene) (PTFE) tubing. TCE extracted into the reagent solution was consequently reacted in the reaction coil at 75°C. The detection was carried out at 550 nm. The blank absorbance was 0.005. The concentration which gives twice the peak height of the blank signal was 10^-5v/v%. The relative standard deviation for 10^-3v/v% TCE was 3.5% (n = 7). Chloroform showed a small signal, 8.4% of that for TCE, because the coloration of chloroform was relatively slower than that of TCE. Trichloroethane and tetrachloromethane did not interfere. The sampling time was 3 min.

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The amount of carbon in steels was determined by a combination of the nonaqueous titrimetry and the acid decomposition method : carbon dioxide evolved from steels after acid decomposition (H₂SO₄+H₂O₂) was absorbed to dimethylformamide containing 2-aminoethanol and titrated with tetrabuthylammoniumhydroxide. Results obtained were as follows : (1) This method is available up to 5μg carbon. (2) Sulfur (sulfur dioxide) interfered the titration. Activated manganese dioxide was required to eliminate the interference. (3) Hydrocarbons were formed by reaction of acid and steels. (4) The precision of this method was about 1% evaluated as R.S.D.

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Determination of hydrogen by thermal conductivity detector (TCD)-gas chromatography using helium as carrier gas was done by oxidation of the hydrogen to water using a copper oxide catalytic converter between the column and detector. 6-port valve switching allowed column effluent to pass through the converter to the TCD or straight to the detector depending upon whether oxidizable hydrogen was eluting in the gas samples tested. Converter bed temperature above 600°C was found suitable for catalysis. Complete regeneration of the reduced copper oxide catalyst was easily done by passing air through the converter during elution of non-hydrogen components. A linear calibration curve for hydrogen was obtained for a range of 0.05100%. Accuracy for hydrogen determination over the concentration range 0.0590% was less than 4.4% relative standard deviation.

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Thirty or more kinds of surfactants were investigated as the dispersing agents. MoS₂/Al₂O₃ catalyst samples were suspended uniformly into an aqueous solution containing triethanolamine/nonylphenylpolyoxyether. A 10μl volume of the sample solution was dropped onto a W-strip heater with an Eppendorf pipette, dried, ashed and atomized in the presence of H₂/Ar purge gas. The unifomity of suspeded powder samples was checked by the determination of Fe in three kinds of test solutions taken from upper, middle and lower positions in a test tube. The three values coincided each other. A good agreement was observed between the analytical result obtained by the proposed method and that obtained as the total amout of aqua regia soluble and insoluble components.

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A selective and sensitive method for the determination of taurine by GC is described. Taurine was converted into its N-isobutoxycarbonyl dibutylamide derivative by the procedure reported previously {Bunseki Kagaku, 34 128 (1985)}, and analyzed by GC with flame photometric detection (FPD-GC) using DB-1 capillary column. By FPD-GC, a linear calibration curve was obtained in the range of 0.25.0 nmol of taurine, and the detection level was about 20 times more sensitive than that obtained by GC with flame ionization detection. Taurine in biological sample could be measured without any influence of coexistent substances. The recoveries of taurine added to mouse tissues and biological fluids were 96107% and the reproducibility was found to be satisfactory. Analytical results of taurine contents in mouse tissues during growth are also presented.

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The simultaneous determination of silver and copper by graphite furnace AAS was investigated by utilizing the difference of appearance temperature. Silver was atomized earlier in graphite furnace than copper and each absorption peak was separated on the absorbance-time profile. Since the resonance lines of silver (328.07 nm) and copper (327.40 nm) are too close to separate by the monochromator used for conventional AAS, the radiation of silver and copper from hollow cathode lamps could be introduced in the same spectral band-width of the monochromator. When the mixed radiation was passed through the graphite furnace, two peaks corresponding for silver and copper appeared in the absorbance-time profile. The addition of palladium or platinum to the sample solution as matrix modifier could enhance the absorbance of silver and improve the separation of both peaks without mutual interference. By measuring each peak height on the absorption profile, the simultaneous determination of silver and copper could be achieved.

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A simple, fast, selective and sensitive method for the determination of ammonium ion in water by ion-exclusion chromatography (IEC) with an anion-exchange resin in the hydroxide-form, followed with a cation-exchange membrane reactor in the potassium-form was developed and applied to the determination of ammonium ion in water of a batchwise activated sludge process for removal of nitrogen. The cation-exchange membrane reactor enhanced the conductivity of ammonium ion in the effluent of the IEC separation by 6-fold by converting ammonium hydroxide to potassium hydroxide by cation-exchange reaction with potassium hydroxide as a regenerant. The calibration graph was linear over the concentration range 0.5 to 5 mM. The method could be applicable to the determination of ammonium ion in some actual samples with satisfactory result.

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Decomposition methods for the determination of Al, Fe, Na, K and Ba in JLs-1 (Limestone) and JDo-1 (Dolomite) samples issued from Geological Survey of Japan were examined to clarify the accurate chemical composition of these samples. Total Fe content was easily obtained by digestion methods using hydrochloric, nitric and perchloric acids, whereas total contents of Al, Na and K could not be obtained by acid-decomposition methods without hydrofluoric acid. Similarly, acid-decomposition methods did not give an accurate total Ba content probably due to the incomplete dissolution of barite. Trace amounts of Na and K in these samples were hard to determine due to the difficulty in preparing calibration curve matched for sample matrices and the laboratory contamination of these elements.

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A simple hydride-generation/AAS method was investigated for determination of trace amounts of tin, mono-, di-and trimethyltin, and monobutyltin compunds in environmental waters. Tin and organotin species in the 100 ml of sample, acidified to pH 2, were selectively reduced to the corresponding hydrides by the addition of 1 ml of 4% sodium tetrahydroborate solution. Volatile tin hydrides formed by the reduction were stripped out by a bubbling helium stream (120 ml/min), and collected in a gas trap cooled with liquid nitrogen. The trap was then warmed slowly. Tin hydrides were separated by fractional volatilization and measured with argon-hydrogen flame AAS. Under the analytical conditions proposed here, the calibration curve for each of five tin species was linear up to 15 ng of tin. The limit of detection (3σ) for tin was 0.3 ng, and the relative standard deviations for the samples containing 4.9 and 11.2 ng of tin in 100 ml (n=4 and 5) were 3.1 and 2.2%, respectively. Analytical results for tin and methyltin compounds in sea-, river and rainwater samples are presented.

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An XRF method using a Sc X-ray tube was investigated for analyses of iron and steel samples. For the determination of S, P, Si, Al and C, the sensitivities obtained with the Sc X-ray tube were two times higher than those obtained with a Rh X-ray tube. Precisions were also improved for the determination of these light elements by using the Sc X-ray tube. This XRF method was applied to the determination of carbon in high speed tool steel standard materials provided by the Iron and Steel Institute of Japan. The accuracy of this method was estimated to be 0.023 % for carbon contents of 0.761.23 %.

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