BUNSEKI KAGAKU
Print ISSN : 0525-1931
Volume 28, Issue 11
Displaying 1-20 of 20 articles from this issue
  • Ikuei KIFUNE, Mie IWATANI, Kuniaki KAWATA
    1979 Volume 28 Issue 11 Pages 633-637
    Published: November 05, 1979
    Released on J-STAGE: January 18, 2010
    JOURNAL FREE ACCESS
    A simple and rapid method was developed for the measurement of atmospheric ammonia using a reaction of indophenol dye formation. A glass fiber filter having the area of 17.3cm2 was impregnated with the reagent for the collection of atmospheric ammonia; the reagent used was a 3% boric acid-20% glycerin solution and a 8.6% oxalic acid-50% glycerin solution. This filter was placed in a filter holder and connected to a vacuum pump drawing air at a flow rate of 20l/min. After sampling, the filter was washed with 20ml of water to extract ammonia. To a fixed volume of extract, each 5ml of a phenol-sodium nitroprusside solution and a sodium hypochlorite solution was added, and after developing color the absorbance of the solution was measured at 640nm. Collection efficiency of atmospheric ammonia by the filters was almost 100%. The lower limit of determination of atmospheric ammonia was 0.84 ppb for a filter having 17.3 cm2 of effective filtering surface at the flow rate of 20l/min, for 1 h sampling period. The sensitivity of this method is higher than that (16.7 ppb) of the indophenol method using an impinger for collection, that is the new method is almost 20 times as sensitive as the conventional one. The coefficient of variation was 5.3% for a range of ppm level. Besides its greater sensitivity, this technique also had advantages in the field, in the preservation of the sample and in ease of transporting the equipment.
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  • Ikuei KIFUNE
    1979 Volume 28 Issue 11 Pages 638-642
    Published: November 05, 1979
    Released on J-STAGE: January 18, 2010
    JOURNAL FREE ACCESS
    A New procedure for the determination of trace phenol and cresols in the atmosphere was examined. A air sample was passed through a 17.3cm2 of glass wool filter impregnated with a solution containing 10% sodium hydroxide and 30% glycerine at a rate of 5l/min. The phenol and cresol were collected quantitatively under the above conditions. The compounds absorbed on the filter were dissolved into ethyl ether and 10 N phosphoric acid mixture (5:1, v/v), the aliquot of the ethyl ether layer was introduced into a gaschromatograph with FID. The recovery of this procedure for the phenol and cresols were approximately 100%, the coefficients of variation in the determination of phenol or cresols were less than 7%. In the case of a extreme low concentration, the extract layer should be concentrated to a small volume and recovery of phenol or cresols was over 96%. The detection limits of this method were from 2.7 to 3.6 ppb for cresols and 3.3 ppb for phenol using a 500cm2 alkali-glycerine filter for 5 min at an air flow rate of 120l/min. The detection limit was low enough to detect the smell limit. There were no interferences by other gases in this method and the phenol and cresols adsorbed in the filter could be kept for a long time without chemical change. This method was applied to the assay of the atomosphere near a foundry as a bad smell substance test and brough good results as well as simplicities in preparation, transportation, sampling, and storing samples.
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  • Shigehiko HAYASHI, Kinuyo USAMI, Kazunobu HIRATA, Keiya KOTSUJI
    1979 Volume 28 Issue 11 Pages 643-647
    Published: November 05, 1979
    Released on J-STAGE: January 18, 2010
    JOURNAL FREE ACCESS
    The collection of copper(II) from 50 ml of 1×10-5M copper salt solution was attempted with 0.1g of dithiocarboxyaminoethylcarbamoylcellulose (D-cell) prepared by the present authors. A satisfactory recovery of copper (II) was achieved over the range of pH 1.3 to 5.9 by stirring the solution together with the D-cell for 30 min at room temperature. Although dithiocarbamate, carboxyl and aminoethylcarbamoyl groups have been introduced to the D-cell as the functional groups, only dithiocarbamate groups seemed to participate to the retention of copper (II) from a solution of pH below 2.0. The collection of copper (II) from 1 M sodium nitrate solution and also from 1 M calcium nitrate solution at pH 4.6 to 4.8 was satisfactorily complete. The optimum pH range was shifted to 1.9 to 5.9 when the collection was done from 1 M sodium chloride solution. The collection of copper(II) was also achieved from 0.1 M sodium bromide solution and from 0.01 M sodium iodide solution at pH 5.0 to 5.3. Various complexing agents such as citrate, cyanide, thiocyanate and EDTA were found to interfere the collection of copper with the D-cell; especially in the presence of cyanide no retention of copper (II) on the D-cell was allowed even at a low concentration of 0.001 M. In the present work, therefore, 0.1 M potassium cyanide solution was effectively used to desorb or release copper(II) from the D-cell after the collection. For example, 63.6μg of copper(II) was desorbed quantitatively from the D-cell by stirring it in 10 ml of 0.1 M pottasium cyanide solution for 30 min at room temperature. Other heavy metals such as manganese (II), cobalt (II), nickel (II) and zinc (II) were not collected on the D-cell at pH 4.0, and therefore, copper(II) can be separated from these metal ions by the treatment with the D-cell in the range of pH 1.3 to 4.0.
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  • Tetsumasa ITO, Hiroshi KAWAGUCHI, Atsushi MIZUIKE
    1979 Volume 28 Issue 11 Pages 648-653
    Published: November 05, 1979
    Released on J-STAGE: January 18, 2010
    JOURNAL FREE ACCESS
    Effects of ethanol on the spectral emission intensities and impedance of an inductively coupled plasma were estimated. The reflected plasma resistances were computed from each value of circuit components of a matching network. The results showed that the plasma resistance increased and accordingly the reflected resistance decreased with increase of the ethanol concentration or with decrease of the RF power. The effect of ethanol on the plasma resistance became smaller as the RF power was increased. Difficulty in tuning the matching network by the introduction of organic solvent is explained by the fact that the slope of a tuning curve becomes steeper than that for the aqueous samples. A suitable tuning procedure for samples dissolved in organic solvents proposed.
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  • Yoshiko ARIKAWA, Shoji HIRAI, Takejiro OZAWA
    1979 Volume 28 Issue 11 Pages 653-657
    Published: November 05, 1979
    Released on J-STAGE: January 18, 2010
    JOURNAL FREE ACCESS
    A method for the determination of selenium and tellurium in native sulfur has been investigated by means of atomic absorption spectrophotometry. Native sulfur collected from around fumarole or volcanic crater is ground down into powder, a portion of which weighing 1 g is subjected to analysis. A 2.6% (w/v) sodium hydroxide solution is added by 10 ml to the sample in a teflon beaker, and the mixture is then heated on a hot plate. Sulfur is decomposed and dissolved in the form of disulfide and thiosulfate. A 30% hydrogenperoxide solution is added by 10 ml to oxidize them to sulfate. At the same time selenium and tellurium contained in the sulfur sample are also thought to be oxidized to Se (VI) and Te (VI) states. The solution is neutralized with hydrochloric acid and diluted with distilled water to 100 ml. The sample solution thus prepared is sprayed into the air-acetylene flame of the atomic absorption spectrophotometer. The absorbance is measured at 195.9 nm for selenium and 214.2 nm for tellurium. Calibration curve is prepared by measuring the absorbances of the solutions prepared as follows. One gram portions of pure sulfur (99.9999%) are decomposed as for the samples. After neutralization, standard solutions containing each same amount of selenium and tellurium (01000μg) are added to the sulfur solution and then diluted with water to 100 ml. The standard deviations were estimated to be 50.4 ppm for selenium at 756 ppm and 16.6 ppm for tellurium at 587 ppm. For the check of the reliability of the method, results were compared with those obtained by neutron activation analysis. Results obtained by both methods showed good agreement.
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  • Nobuhiko ISHIBASHI, Teiichiro OGAWA, Totaro IMASAKA
    1979 Volume 28 Issue 11 Pages 657-660
    Published: November 05, 1979
    Released on J-STAGE: June 19, 2009
    JOURNAL FREE ACCESS
    A very sensitive apparatus was constructed for measurements of trace concentrations of NO2 in the air. The apparatus consisted of a nitrogen-laserexcited dye laser, a low-background sample cell, a double monochromator, and a gated photon counter. Two monitoring techniques have been investigated: a direct method and a trap method. The direct method is to measure the fluorescence signal of the flowing sample directly. The minimum detectable concentration was 0.6 ppm. The advantage of this method is its reliability which comes from the calibration of the absolute value of NO2 concentrations through the simultaneous determination of the intensity of Raman lines of N2 and O2. In the trap method, the gas sample was flowed through a liquid nitrogen trap. After several minutes of trapping, the sample was degassed and then expanded into the fluorescence cell. Not only the increase of concentration but also the increase of fluorescence quantum efficiency of NO2 upon the reduction of pressure allowed the detection of lower concentration; the detection limit was 0.02ppm. The present method is more reliable than the reported methods, because the monochromator is useful in removing any interferences of the fluorescent contamination and in reliable calibration of concentration by comparing the intensity with the Raman line.
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  • Kimiko HORIUCHI, Yukio MURAKAMI
    1979 Volume 28 Issue 11 Pages 661-665
    Published: November 05, 1979
    Released on J-STAGE: January 18, 2010
    JOURNAL FREE ACCESS
    220Rn in mineral springs is easily extracted into toluene solution (containing a definite amount of liquid scintillator), which is carefuly transferred into counting vial. The activity in the solution is measured by integral counting technique with a liquid scintillation counter. 220Rn, being extracted, rapidly disappears but 212Pb (half-life 10.64 h) and its descendants form a radioactive equilibrium in toluene solution around 3.7 h after the extraction. The establishment of radioactive equilibrium is proved by α and β rays energy spectrum and also by the formation of growth decay curve. The shape of this curve entirely coincides with decay curve constructed by application of the Bateman equations for 212Pb and its descendants. It was proved that integral counting technique could practically give hundred percent counting efficiency for 1α and 2β emitters in radioactive equilibrium. A calculating formula for 220Rn contents in water is proposed based upon these facts, together with necessary correction terms such as extractability, decay rate during measurement and so on. The detection limits of this method is found as (6.8±0.9)×10-10 Ci (standard deviation in counting) under the conditions of 5 cpm (one tenth of background counting rate) and total counting time of 400min. Some practical examples of determination of 220Rn in mineral springs are shown together with 222Rn contents to prove the availability and feasibility of this method.
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  • Yukio TATENO, Naoichi OHTA
    1979 Volume 28 Issue 11 Pages 666-671
    Published: November 05, 1979
    Released on J-STAGE: January 18, 2010
    JOURNAL FREE ACCESS
    A combination of electrodeposition on graphite with neutron activation analysis was used for the determination of gold and indium in sea water. At a potential of -0.70 V vs. the silver-silver chloride electrode, gold and indium were electrolyzed on to a graphite electrode (1.1cmφ × 0.2cm) from 100ml of 0.5M sodium chloride. Recovery yield of gold was constant at pH from 1 to 3 and was independent of the initial concentration of gold, (0.011) ppb. For a 72-h electrolysis at pH 2 the recovery yield of gold was 92%, while that of indium was 32%. The graphite electrode was exposed to a thermal neutron flux of 5.1×1011 or 1.5×1012n cm-2 s-1: 5min exposure for indium and 6 to 12 h for gold. After appropriate decay periods the activities of 198Au and 116mIn were measured for 2000s and 300s, respectively, with a 4000-channel pulse-height analyser and a Ge (Li) detector. The total amount of gold in 1 l of a sea water sample (Tokyo Bay) was (0.023 ± 0.001) μg, in which nonelectrolyzable gold was estimated to be 0.005μg. Indium concentration in the sample was too low to be determined by the present method. Detection limit for indium was 1 ppb.
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  • Yoshihito SUZUKI, Masahide MARUYAMA
    1979 Volume 28 Issue 11 Pages 671-675
    Published: November 05, 1979
    Released on J-STAGE: June 19, 2009
    JOURNAL FREE ACCESS
    As new method of derivatization connected with HPLC, the rapid derivatization using thermal-reaction column is described. The outline of this as follows. Aqueous solution aldehyde is injected to thermal-reaction column that has been packed with 2, 4 dinitrophenylhydrazine supported on Celite 545 {(80100) mesh} and heated at 100°C. Then, thermal-reaction column is connected to HPLC instrumentusing 6-way valve and the thermal reaction products (2, 4-dinitrophenylhydrazone, etc.) are transferred by mobile phase (H2O-MeOH, 40/60) into the analytical column packed with ODS-silica, i.d. 4mm, length 25cm. They were separated to peaks of each components and detected at 350 nm which is specific absorption of 2, 4-DNPH. The method of quantitation is peak-area calibration procedure using disc integrator. As a result, it was found that the thermal-reaction proceeded quantitatively. Therefore, it was possible to determine amounts of 10 ng aldehyde rapidly and simply. As a practical example, we applied this method to the quantitative analysis of acetaldehyde in wines.
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  • Sigeo TANUMA, Kozo NAGASHIMA
    1979 Volume 28 Issue 11 Pages 675-680
    Published: November 05, 1979
    Released on J-STAGE: January 18, 2010
    JOURNAL FREE ACCESS
    In X-ray microanalysis, direct determination of oxygen content is inevitable for the oxide-sulfide samples which contain both O2- and S2- not in the form of So42- group but at the equivalent or the similar sites. X-Ray intensity was measured as the peak area of the oxygen Kα. For antimony, sulfur, calcium, manganese and iron the peak height was directly measured as their X-ray intensities. The ZAF correction was made for all the data obtained. The standard materials were Sb2O3 (synthetic) for oxygen and antimony, Sb2S3 (stibnite) for sulfur and antimony, CaSiO3 (wollastonite) for calcium, Mn (metal) for manganese, and Fe (metal) for iron. Experimental results and the ideal formulas in the parenthese are as follows;kermesite : Sb1.94S1.95O (Sb2S2O), sarabauite:Ca0.94Sb9.85O10S5.71(CaSb10O10S6), synthetic sarabauite Ca0.97Sb10.27O10S6.15, synthetic schafarzikite : Fe0.87Sb1.90O4(FeSb2O4), synthetic manganese antimony oxide : Mn1.06Sb2.10O4(MnSb2O4). The relative error of oxygen content between the experimental and the theoretical results ranges from-4.42% to 7.84%. The coefficient of variation of the intensity of oxygen Kα in Sb2O3, used as a standard, was less than 1.09 %.
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  • Hiroshi HASHITANI, Hideyo YOSHIDA, Takeo ADACHI
    1979 Volume 28 Issue 11 Pages 680-685
    Published: November 05, 1979
    Released on J-STAGE: June 19, 2009
    JOURNAL FREE ACCESS
    Acetylacetone is proposed to use as a demasking agent for determination of fluoride most of which forms anionic complex with aluminum in environmental water samples. Acetylacetone forms a stable and colorless chelate with aluminum. It is also efficient to prevent the formation of aluminum alizarin complexone (ALC) chelate which gives apparent negative error in lanthanum-ALC photometry. By use of acetylacetone, aluminum ten times as much as fluoride does not interfere in the photometry, and 1 mg of aluminum is permissible in the potentiometry using fluoride-selective electrode. Other interferring metals (Co, Cu, Ni, Zr) are removed by taking the supernatant of the sample which has been made alkaline (pH 12). Lanthanum-ALC photometry.-Dissolve 2 ml of acetylacetone in 25 ml of sample containing 3 to 50 μg of fluoride, with stirring. Add 2 ml of sodium acetate-acetic acid buffer (pH 5.0), 5.0 ml of 5.0 % lanthanum-ALC (Dotite Alfusone) and 10 ml of acetone, and dilute to mark with water in 50 ml flask.Measure the absorbance at 620 nm against blank. Potentiometry.-Dissolve 1 ml of acetylacetone in 40 ml of sample containing more than 8μg of fluoride, with stirring. Add 2 ml of 1 M sodium citrate, adjust the pH to 7.0 to 7.5 with 2 M sodium hydroxide or 2 M hydrochloric acid and dilute to 50 ml with water.Immerse electrodes in the solution and observe the meter reading while mixing.
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  • Itsuo MORI, Yoshikazu FUJITA, Takehisa ENOKI
    1979 Volume 28 Issue 11 Pages 685-690
    Published: November 05, 1979
    Released on J-STAGE: January 18, 2010
    JOURNAL FREE ACCESS
    A highly sensitive method for the spectrophotometric determination of palladium(II) with ο-hydroxyhydroquinonephthalein (Qn.Ph.) and low concentration of quaternary ammonium salts in the presence of methylcellulose (MC) have been developed. Qn.Ph. forms a pure cobalt blue complex with palladium(II) in a weakly acidic medium in the presence of low concentration of cetyltrimethylammonium bromide (CTAB) as a cationic surfactant and an excess of MC as a nonionic surfactant. The color of the palladium(II)-Qn.Ph. complex was very stable and was used for the spectrophotometric determination of palladium(II) in aqueous solutions of pH 5.0. The absorbance of the complex remained constant when the pH was adjusted from 4.7 to 5.5 with Walpole buffer solution. The maximum absorption wavelength of palladium(II)-Qn.Ph. complex in the presence of MC and low concentration of CTAB was 625 nm, and in the presence of excess CTAB was 580 nm against water. A calibration curve was linear up to 6 μg/10ml palladium(II) at 625 nm against water. The recommended procedure for the determination of palladium(II) is as follows. A sample containing (1.06.0) μg of palladium(II) is taken in a 10.0 ml measuring flask, then 1.0 ml of 0.5% MC solution, 1.5 ml of 1.0×10-3 M CTAB solution, 2.0 ml of Walpole acetate buffer solution and 0.5 ml of 1.0×10-3 M Qn.Ph. methanol solution are added. The whole volume is brought to the mark with distilled water, and the solution is kept at 60°C for 30 min, then the absorbance of Qn.Ph.-palladium(II) solution is measured at 625 nm against water. The effect of foreign ions on the absorbance of the complex were examined.Iron(II), copper(II), aluminum(III), chromium(III) etc. interfered, and then copper(II), aluminum(III) could be masked by the addition of citric acid solution. The mole ratio of palladium(II) : Qn.Ph. : CTAB in the complex was estimated to be 2 : 3 : 2 by the continuous variation method and the mole ratio method. The apparent molar extinction coefficient at 625 nm is 1.27×105. The recovery of this method is 94.4%100.2%. This method is applicable to the analyses of palladium(II) in the catalyzers of palladium black and palladium asbestos.
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  • Hideo AKAIWA, Hiroshi KAWAMOTO, Makoto KONISHI
    1979 Volume 28 Issue 11 Pages 690-695
    Published: November 05, 1979
    Released on J-STAGE: January 19, 2010
    JOURNAL FREE ACCESS
    A highly selective method was developed for the separation of nickel(II) from manganese(II), cobalt(II), copper(II), zinc(II), cadmium(II), mercury(II), silver(I) and lead(II) with a mixture of dithizone and 1, 10-phenanthroline by employing the back-extraction technique. The established procedure is as follows: Adjust the pH of a sample solution to ca. 8.5 by adding nitric acid or ammonia, and add 20 cm3 of chloroform containing 0.02% dithizone. Shake the mixture for 30 min, and allow the phases to separate.Transfer 15 cm3 of the organic phase to another separatory funnel containing an equal volume of an aqueous nitric acid solution of pH 1.5. Extract manganese(II), zinc(II), cadmium(II) and lead(II) into the aqueous phase by shaking the mixture for 30 min.Take 10 cm3 aliquot of the organic phase into another separatory funnel containing 20 cm3 of an aqueous solution of pH 1.5, and add 10 cm3 of chloroform olution of 0.002 mol dm-3 1, 10-phenanthroline. Then, shake the mixture for 30 min. The resulting aqueous phase contains only nickel(II). For the determination of nickel(II), take an aliquot of the aqueous phase, and adjust the pH to ca. 11.5 by adding ammonia. Add 10 cm3 of chloroform containing 0.001% dithizone and 0.02 mol dm-3 1, 10-phenanthroline and shake the mixture for 10 min. Measure the absorbance of the organic phase at 514 nm against the reagent blank. Beer's law is obeyed and the molar absorptivity is 49500 dm3mol-1cm-1. Recovery of nickel(II) was 96% in the presence of each 20μg of cobalt(II), copper(II), zinc(II) and cadmium(II). Iron(II) (≤100μg) can be masked with tartrate. A. large amount of iron(III) should be removed preliminarily by MIBK extraction.
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  • Hiroshi MIZUNUMA, Hideyoshi MORITA, Hiromu SAKURAI, Shigeru SHIMOMURA
    1979 Volume 28 Issue 11 Pages 695-699
    Published: November 05, 1979
    Released on J-STAGE: January 18, 2010
    JOURNAL FREE ACCESS
    A method for the selective determination of inorganic and organic mercury in aqueous solution is described. The method is based on the selective reduction of inorganic mercury with NaBH4 in an alkaline solution (pH 10), and based on the finding that both inorganic and organic mercury compounds are decomposed and reduced by a combined use of Fe(III) and NaBH4 in an aqueous solution of pH 28. The determination procedures are as follows: (A) Determination of inorganic mercury; An aliquot (100 ml) of sample solution was taken into a reaction vessel, and the pH of the solution was adjusted to 1012 with 1 N sodium hydroxide. To the solution 2 ml of 1% (w/v) NaBH4 solution was added, and the mixture was stirred for 5 min. Then the evolved mercury vapor was measured with an atomic absorption spectrophotometer. (B) Determination of total mercury; An aliquot (100 ml) of the sample solution was taken into the reaction vessel, and the pH of the solution was adjusted to 23 with 1 N sulfuric acid. To the solution 2 ml of 1×103 ppm Fe (III) and 2 ml of NaBH4 solutions were added successively, and the mixture was stirred for 5 min. Then the evolved mercury vapor was measured with the atomic absorption spectrophotometer. The organic mercury of the sample solution was determined by the differences between the values obtained by the above two procedures. The method is useful in the range of (0.28) ppb with a standard deviation of 2% at 5 ppb. The method was satisfactory for river and waste water samples.
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  • Mitsuo ABE, Kenji HAYASHI
    1979 Volume 28 Issue 11 Pages 700-702
    Published: November 05, 1979
    Released on J-STAGE: June 19, 2009
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    Interference of sodium was measured for the determination of micro quantity (2μg cm-3) of lithium in the solution containing sodium nitrate or sodium chloride by atomic absorption spectrophotometry and flame photometry with air-acetylene flame. A solution containing lithium of 2μg cm-3 in 0.1 M nitric acid was used as a reference solution, because the depression in nitric acid was within experimental error (<1%) in a range of (0.050.5)M in the preliminary experiment for the effect on the signal of lithium in nitric, hydrochloric, and perchloric acid. For atomic absorption spectrophotometry no interference was observed in a range of (0.257)μg cm-3 of sodium concentration, while the enhancement of (25)% was measured for (251000)μg cm-3 and the increased depression at higher concentration than 1000μg cm-3. Less depression was noticed in sodium nitrate solution. Similar interference was observed in the systems of the various acid and salt solutions by flame photometry.
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  • Takeo TAKAKU, Akira OTSUKI, Masayuki TAKAHASHI
    1979 Volume 28 Issue 11 Pages 702-704
    Published: November 05, 1979
    Released on J-STAGE: June 19, 2009
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    Reversed phase adsorption high pressure liquid chromatography was examined to develop a simple and rapid method for the determination of Fenitrothion {O, O-dimethyl (3-methyl-4-nitrophenyl) phosphorotioate} in water. A diphenylsilane chemically bonded glass beads column was found to be useful for the adsorption of Fenitrothion in water. Fenitrothion is adsorbed from sample water directly injected on the diphenylsilane bonded beads and eluted as a sharp peak by a linear gradient elution from water to 100% acetonitrile. The peak height detected at 280 nm was proportional to the amount injected in the range from 0 to 800 ng. The recovery of Fenitrothion from fortified distilled water and pond water at sub-ppb level was (97.8±0.25)% and (95.6±1.10)%, respectively.
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  • Megumu KUDOH, Masamitsu KATAOKA, Tomihito KAMBARA
    1979 Volume 28 Issue 11 Pages 705-707
    Published: November 05, 1979
    Released on J-STAGE: June 19, 2009
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    Construction of a liquid membrane type ion-selective electrode sensitive to divalent histaminium cation and its application to potentiometric titration are described. Histamine cation (abbreviated as H2his2+) forms an ion-pair with tetraphenylborate anion (abbreviated as TPB-) in aqueous phase. The extract shows the property of histamine cation-sensitive membrane. Platinized platinum electrode was employed as the internal reference electrode. The calibration curve of the electrode shows a Nernstian response for H2his2+ ion in the concentration range from 10 mM to 15μM. Effect of pH on the electrode potential was observed and the potential is almost constant over the pH range from 1.5 to 6.0. Selectivity coefficients of the histaminium ion-selective electrode was evaluated by means of the separate solution method. Some quaternary ammonium cations showed serious interferences. Sodium tetraphenylborate standard solution was successfully titrated with histamine solution potentiometrically by using the present electrode.
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  • Itsuo MORI, Yoshikazu FUJITA, Takehisa ENOKI
    1979 Volume 28 Issue 11 Pages 707-710
    Published: November 05, 1979
    Released on J-STAGE: January 18, 2010
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    ο-Hydroxyhydroquinonephthalein (Qn. Ph.)-chromium(VI) {Cr(VI)} complex in the presence of excess cationic surface-active agent (cetyltrimethylammonium chloride) (CTAC) could be used for the spectrophotometric determination of a minute amount of Cr(VI). A maximum absorption wavelength of the complex was 560 nm in a weakly acidic medium, where the apparent molar absorption coefficient was 1.64×105. The Sandell sensitivity was 0.00032μg/cm2 Cr(VI) for an absorbance of 0.001 at the wavelength of 560 nm. The calibration curve was linear in the range 0 to 4μg/10ml Cr(VI). The proposed procedure for the determination of Cr (VI) is as follows. To a 10 ml volumetric flask a sample solution containing less than 4 μg of Cr(VI), 1.0 ml of 2.0×10-2 M CTAC solution and 2.0 ml of 1.0×10-3 M Qn. Ph. methanol solution are added, and the pH of the mixture is adjusted to 5.8 by the addition of Sorensen buffer solution of phosphate. The content is diluted to the mark with water, kept at 60°C for 30 min, and the absorbance of the solution is measured at 560 nm against the reagent blank. The reaction is quite sensitive, and the procedure does not require a long time. This method is applicable to the determination of Cr(VI) in steel in much the same way as previous by reported determination of molybdenum(VI). The mole ratio of Cr(VI), Qn. Ph. and CTAC in the complex was estimated to be 1 : 2 : 2 by the continuous variation and the mole ratio methods.
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  • Michio ZENKI, Katsuji IWAKI
    1979 Volume 28 Issue 11 Pages 710-712
    Published: November 05, 1979
    Released on J-STAGE: June 19, 2009
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    Spectrophotometric determination of vanadium with 3-N-salicylideneamino-4-hydroxybenzenesulfonic acid (SAPS). has been studied. SAPS easily reacts with vanadium in aqueous solution forming a yellow complex. The complex has an absorption maximum at 420 nm and a maximum absorbance is obtained in the pH range from 4.0 to 6.5. Beer's law holds over the range of 0100μg/25 ml of vanadium and the apparent molar absorption coefficient of the complex is 1.14×104 l mol-1 cm-1. Trace amounts of aluminum(III), copper(II), iron(III) and molybdenum(VI) interfere with the determination but these interferences except molybdenum can be masked by adding thiourea and sodium fluoride. The established procedure is as follows. Transfer the sample solution containing up to 100μg of vanadium to a 25 ml volumetric flask. Add 5 ml of acetate buffer (pH 5.0) and 5 ml of 0.1% SAPS solution. Dilute to the mark with water and measure the absorbance at 420 nm using the reagent blank as reference. The proposed method is simple and rapid, then applied to the analysis of steel for vanadium. Large amounts of iron can be removed by ethyl ether extraction method in 6 N hydrochloric acid solution. Vanadium (0.10.3)% in iron and steel samples can be determined successfully.
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  • Kunio OHZEKI, Toshiaki SAKUMA, Tomihito KAMBARA
    1979 Volume 28 Issue 11 Pages 713-714
    Published: November 05, 1979
    Released on J-STAGE: June 19, 2009
    JOURNAL FREE ACCESS
    Finely divided ion exchange resin particles can collect ions from solution more rapidly than the beads of conventional size, and by the addition of oppositely charged resin particles, they coagulate each other to form a bulky material which is easily separated by filtration. The coagulated resins are collected on a filter paper as a uniform and thin layer which is directly subjected to the spectrophotometric measurements. A trace amount of chromium(VI) is determined as follows. A 100-ml sample solution containing less than 1.0μg of chromium(VI) and sulfuric acid in the concentration of approximately 0.01 mol dm-3 is taken into a separatory funnel. Then 3.0 ml of anionic resin suspension (7.22×10-3 meq ml-1), 1.0 ml of cationic resin suspension (13.3×10-3 meq ml-1) and finally 1 ml of 0.4% diphenylcarbazide in 50% acetonewater solution are added. The mixture is shaken for 12 min and the resulting coagulated material is collected onto a filter paper (Toyo Roshi No. 5A) set on a holder. The purple colored resins thus obtained form a disk of 17 mm diameter and about 0.3 mm in thickness. To stabilize the coloration, the filter strip is dipped into an acetate buffer solution for 10s and then the absorbance is measured against reagent blank at the absorption maximum of 550 nm and at 700 nm where the complex has no absorption. The net absorbance is obtained as the difference. The working curve deviates slightly from the proportionality, the relative standard deviation being 2.1% (n=6) for 1 μg of chronium(VI) and 3.3% (n=5) for 0.4μg. The sensitivity of the present method is approximately 100-fold higher than the ordinary solution method using 1-cm cell. As a 1-μg portion of chromium(VI) is quantitatively recovered from 400-ml sample solution, the sensitivity is 400-fold higher than the ordinary method.
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