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Volume 29, Issue 11
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Kazuo HIRAYAMA, Nobuyuki UNOHARA1980 Volume 29 Issue 11 Pages 733-737
Published: November 05, 1980
Released on J-STAGE: February 16, 2010
JOURNAL FREE ACCESSA highly sensitive method has been developed for the determination of ultratrace vanadium based on its catalytic oxidation of Bindschedler's green leuco base {4, 4'-bis (dimethylamino) diphenylamine, BGL} by potassium bromate. BGL was oxidized to Bindschedler's green (BG) which showed a maximal absorbance at 725 nm. The determination of vanadium was carried out by the fixed time method using the absorbance of BG at 725 nm. A linear relationship was obtained between the absorbance and the concentration of vanadium (IV) in the range of 00.12 ng/ml under the following conditions; BGL: 7.8×10-4 M, potassium bromate: 3.2×10-2 M, F-: 2.1×10-3 M, pH: 3.8, Temp.: 25°C, reaction time: 10 min. In this method, the concentration of vanadium as low as 0.008 ng/ml could be determined, and the sensitivity (absorbance=0.001) was 0.15 pg/ml. The coefficient of variation at 0.06 ng/ml of vanadium was 3.5 % (n=10). Among diverse ions, iron (III) and copper (II) cause an accelerating effect. The interference by iron (III) could be eliminated by the addition of F-. Up to 1000 times for the amounts of vanadium, neither iron (III) nor copper (II) interfere. Even when there were many other ions as 10000 times as the vanadium, they don't interfere. Present method was successfully applied to the determination of trace vanadium in the river and the tap waters.View full abstractDownload PDF (711K) -
Michiko KOJIMA, Noriyo SEKIGAWA, Naofumi SHIGA, Osami MATANO, Shiko GO ...1980 Volume 29 Issue 11 Pages 738-743
Published: November 05, 1980
Released on J-STAGE: February 16, 2010
JOURNAL FREE ACCESSHigh pressure liquid chromatographic method for determining dithianon based on on-line post-column reaction with sodium sulfide was established. This method was applied to residue analysis of dithianon in eleven crops. It is the principle of this method that sodium sulfide solution is added continuously to the column effluent through the mixing tee and then reacted with dithianon in the reactor, and the colored reaction product formed is detected photometrically at 375 nm. The operating conditions were as follows: column, reversed-phase type SC-02 (JASCO) (4.6 mm i.d.×250 mm, stainless steel); mobile phase, 75% methanol (v/v); flow rate, 2.0 ml/min; reaction agent, 3% sodium sulfide added at flow rate of 0.5 ml/min; reactor, bed reactor type 2.1 mm i. d.×50 mm column (stainless steel) packed with non-porous spherical glass beads with mean particle size of 200μm (NGX-2, NISHIO INDUSTRY, JAPAN). By these conditions, the best chromatogram was obtained with respect to the peak height and the peak broadening. Minimum detectable amount was 20 ng and c. v. obtained by five runs at 200 ng was 1.3 %. Calibration curve was linear within a range of (20200) ng. The recommended analytical procedure is as follows. After the crops were homogenized in hydrochloric acid solution (in case of onion, mercuric chloride was added to the homogenate), dithianon was extracted with acetone. The extract was diluted with water, and dithianon was re-extracted into hexane. After the extract was loaded on a column packed with silica gel treated with 10 % (v/w) of 1 N hydrochloric acid {in case of onion and radish, 10 % (v/w) of 50 % silver nitrate was added}, dithianon was eluted with benzene. The effluent was evaporated, the residue was dissolved in methanol containing 1 % acetic acid, and the solution was injected into a liquid chromatograph. The limit of detection was 0.01 ppm for 50 g of sample (0.05 ppm for 10 g of tea). Recoveries from various crops fortified at the 0.2 ppm level (tea; 1.0 ppm) were between 80 % (onion) and 106 % (apple). Any interference was not observed on the chromatogram. This method is simple, accurate, sensitive and selective. It was proved that this method allowed to determine dithianon in various crops in a short time and was applicable to routine analyses.View full abstractDownload PDF (1019K) -
Masahiko NAKAJIMA, Hyoichiro SAKURAI, Akira SAKAI, Kazuo IMAEDA, Keiko ...1980 Volume 29 Issue 11 Pages 744-749
Published: November 05, 1980
Released on J-STAGE: February 16, 2010
JOURNAL FREE ACCESSAn apparatus for oxygen analysis by coulometric titration was developed. A sample {(0.52)mg} is pyrolyzed in a carrier gas. The pyrolyzed gas reacts on Pt-C, with evolution of CO. The CO is subsequently oxidized to CO2 by I2O5. The CO2 gas is absorbed in 5 % Ba (ClO4)2 solution of pH 9.7, thus decreases the alkalinity of the solution. By generating OH-ions coulometrically, the pH is brought back to the initial value; and the quantity of coulombs required is a measure of the absorbed CO2 (1 coulomb=82.9 μg O). Following items were considered to be essential. (1) accurate determination of the end point without excess titrant, (2) minimization of pH shift during titration, (3) elimination of noise caused by intermittent current, (4) one hundred per cent CO2 gas absorption efficiency. In order to fulfill these conditions, (0.055) mA of controlled current were applied in the range of 0.010.10 pH shifts, and 50 mA of constant current was applied when the pH was shifted beyond 0.10 so that the pH shift was controlled below 0.50. To eliminate the induced noise due to switch on and off, 50μA constant current was constantly applied to the generating electrode. A titration cell with a stirrer driven by motor, an airtight oil-impregnated porous metal bearings and baffles was used. The solution absorbed CO2 completely above pH 9.0 under 3000 rpm stirring. The absolute error on analysis of standared organic samples was below 0.3 %. The detection limit was (300500)ng.View full abstractDownload PDF (979K) -
Hitoshi YOSHIDA, Shunitz TANAKA, Mitsuhiko TAGA1980 Volume 29 Issue 11 Pages 749-754
Published: November 05, 1980
Released on J-STAGE: June 30, 2009
JOURNAL FREE ACCESSA remarkable enhancement effect of thiourea on the anodic stripping peak of copper at a hanging mercury drop electrode (HMDE) was observed and used as a sensitive method for the determination of copper. By the addition of thiourea in the supporting electrolyte solution of 0.1 mol dm-3 NaClO4, the stripping peak at -0.08 V vs. SCE decreased and the sharp peak appeared at a more positive potential (-0.01 V vs. SCE). This peak current increased with increasing thiourea concentration up to 1×10-4 mol dm-3 and became about six times as large as that observed in the absence of thiourea. The peak current depended on pH, and the maximum peak current was obtained in the supporting electrolyte solution of pH 3.8 adjusted by the addition of HClO4 or 0.01 mol dm-3 acetate buffer solution. The electro-capillary curves of a dropping copper amalgam electrode (DCAE) showed that the adsorption of thiourea occurred in the vicinity of -0.15 V vs. SCE. Hence the enhancement of a stripping peak was attributed to the adsorption of thiourea on the surface of the electrode amalgamated with copper by the pre-deposition. The peak current was proportional to the copper concentration over a range of (1×10-7?1×10-6)mol dm-3. The relative standard deviation for nine runs at 1×10-6 mol dm-3 Cu(II) was ca. 4 %. The influence of coexisting ions was also studied.View full abstractDownload PDF (895K) -
Takeshi YAMANE, Kiyoteru SETO, Tsutomu FUKASAWA1980 Volume 29 Issue 11 Pages 754-758
Published: November 05, 1980
Released on J-STAGE: February 16, 2010
JOURNAL FREE ACCESSThis paper describes the determination of lead in air-borne particulate matters collected on a membrane filter by use of a low volume air sampler at flow rate of 20 l/min. The particulate matters with the membrane filter were treated with 1 ml of nitric acid by heating on a hot-plate for 15 min and then the filter was completely decomposed with 1.5 ml of sulfuric acid and 1 ml of hydrogen peroxide (60 %). After filtration, the filtrate was transfered to a separating funnel and diluted to ca. 25 ml with water. Lead is extracted with 10 ml of dibenzyldithiocarbamate solution in carbon tetrachloride, and then back-extracted by washing the organic phase with 8 ml of 3.5 N hydrochloric acid solution to separate from other interfering elements. The aqueous phase was transferred to a volumetric flask (25 ml) and adjusted to pH 10.0 with ammonia water. After the addition of 0.02 % solution of 4-(2-pyridylazo)-resorcinol and diluted to the volume with water, the absorbance of the solution was measured at 520 nm. The method allows the determination of lead as low as 1 μg without interference from other elements commonly found in the air-borne particulates and shows good precision.View full abstractDownload PDF (890K) -
Application to the assay for hydrogen peroxide as a food additiveChiyo MATSUBARA, Kiyoko TAKAMURA1980 Volume 29 Issue 11 Pages 759-764
Published: November 05, 1980
Released on J-STAGE: February 16, 2010
JOURNAL FREE ACCESSA simple and rapid method was developed for the determination of trace of hydrogen peroxide using a mixture of titanium (IV) and 4-(2-pyridylazo)-resorcinol (named Ti-PAR reagent) as a color developing agent. The addition of hydrogen peroxide to the reagent results in a red coloration due to the formation of titanium (IV) complex with hydrogen peroxide and PAR. The absorbance at 508 nm was proportional to the concentration of hydrogen peroxide added under the conditions of [PAR]/[Ti(IV)]≤1 and [Ti(IV)]=(3×10-56×10-5) M in pH 7.512. The Ti-PAR reagent itself also exhibits the absorption peak (λmax 523 nm) at pH 8.6 due to the formation of titanium (IV)-PAR complex. However, the latter peak was rather unstable and disappeared rapidly when it was warmed, while the former peak remained unchanged at 45°C over a period of several hours. Then the absorption measurements at 508 nm were performed after heating at 45°C for 5 min. The method was applicable to the determination of hydrogen peroxide in the concentration range of 1×10-6 to 5×10-5 M with a molar absorptivity of 3.6×104 cm-1M-1. The data were reliable with a coefficient of variation below 2.0 %. Little effect was observed by other substances. The method was successfully applied to the determination of hydrogen peroxide added in food, and the lower limit of determination was found to be about 0.3 ppm. A spot test of hydrogen peroxide by dropping the reagent directly to samples was further examined and the lower limit of detection was ca. 2 ppm for white boiled fish-paste.View full abstractDownload PDF (991K) -
Toshihiko TOIDA, Koreharu OGATA, Shinzo TANABE, Toshio IMANARI1980 Volume 29 Issue 11 Pages 764-768
Published: November 05, 1980
Released on J-STAGE: February 16, 2010
JOURNAL FREE ACCESSHigh performance liquid chromatographic analysis of thiocyanate (SCN-) was studied using a visible absorption detector to measure iron (III) complex with SCN-. Iron (III) was also effective as the eluting agent, and a simple chromatographic system was developed. The analytical conditions were as follows: column; TSK-Gel LS-222 (6 μ, 3 mm i. d.×100 mm), eluent; 0.02 M ferric perchlorate in 0.06 N perchloric acid, detector; spectrophotometer connected with 50 μl flow cell (460 nm), flow rate; 0.33 ml/min, column temperature; 40°C. Some anions formed the colored complexes with iron (III), but did not interfere with the measurement of SCN-. The calibration curve was linear within a range of (0.2510)nmol for SCN-. This method was applied to the determination of SCN- in the normal human urine. The analytical procedure was as follows: Urine was centrifuged at 3000 rpm for 10 min. Then 100 μl of the supernatant was injected directly on the column. Recoveries of SCN- added to human urine were (98.2102.3)%.View full abstractDownload PDF (596K) -
Takahiko MATSUEDA, Masahiro MORIMOTO1980 Volume 29 Issue 11 Pages 769-774
Published: November 05, 1980
Released on J-STAGE: February 16, 2010
JOURNAL FREE ACCESSA new indirect atomic absorption method for the determination of linear alkylbenzenesulfonate (LAS) in water is proposed. The method is based on the extraction with methyl isobutyl ketone (MIBK) of the ion pairs formed between LAS and thiourea-copper (I) complex. Addition of thiourea to an aqueous medium containing copper (II) results in the formation of various thiourea-copper (I) complexes which are extractable as ion pairs with LAS into MIBK. Therefore, LAS can be determined indirectly by measurement of copper in the organic phase by atomic absorption spectrophotometry. LAS was pre-separated from foreign anions by extraction with MIBK in the presence of sodim chloride. The effect of sodium chloride concentration on the extraction of LAS with MIBK, and the effects of the molar ratio of copper (II) to thiourea and the concentration of thiourea-copper (I) complex on the determination of LAS were examined. The recommended procedure is as follows: Place a water sample solution containing not more than 200 μg of LAS, in a 120 ml graduated test tube, and 10 ml of the 30 w/v % sodium chloride solution, and then adjust the volume to 100 ml with water. Add 10 ml of MIBK. Shake for 3 min and allow to stand for 5 min. Pipette a 5 ml aliquot of the MIBK layer into a 15 ml test tube, containing 5 ml of the thiourea-copper(I) complex solution (Cu: 2×10-3 M thiourea: 8×10-3 M), and shake for 3 min. Aspirate the MIBK layer directly to atomic absorption apparatus and measure the absorbance of copper. The linear relationship was observed between the absorbance and the concentration of LAS in the range of (0.01?20)μg/ml, and the coefficient of variation was 2.4 % at 0.1 μg/ml of LAS. Such anions as SCN-, NO2-and I- interfered with the determination of LAS, but their interference could be removed by washing with the 0.1 M sodium borate solution and then with the 0.1 M phosphate-hydrochloric acid buffer solution of pH 3. The presence of CN- and cationic surfactants interfered strongly. The proposed method was compared with the methylene blue method for the sample solution such as river water and sewage water. The values determined by the proposed method agreed very closely with those obtained by the methylene blue method.View full abstractDownload PDF (1016K) -
Atsuo NISHIOKA, Yasuo MUKAI, Muneki OOUCHI, Mamoru IMANARI1980 Volume 29 Issue 11 Pages 774-780
Published: November 05, 1980
Released on J-STAGE: June 30, 2009
JOURNAL FREE ACCESSCarbon-13 NMR analysis of chain branching in low density polyethylene (LDPE) at 25 MHz has revealed the existence of four kinds of complex chain branching, besides more than four kinds of well known isolated branches. A well resolved carbon-13 spectrum consisting of 33 peaks has been observed for a LDPE sample with use of 90 deg. pulses applied at equilibrium magnetization with 40 s interval and accumulating 4320 times. To attain reasonable assignments of all the carbon atoms which play roles in branching signals, four kinds of additivity rules of carbon-13 chemical shifts, that is, Grant-Paul, Lindeman-Adams, Randall, and Yamamoto's methods have been applied. Taking into account of the double back-biting scheme in the polymerization mechanism of LDPE, 1, 3-ethyl pair, 5-ethyl-hexyl, tetrafunctional butyl, and tetrafunctional butyl-ethyl branches have been found to exist in this polymer, besides the isolated branches such as ethyl, butyl, amyl, and hexyl+, including longer chains. Among these branches butyl type is the highest in abundance. Among the four kinds of additivity rules, Lindeman-Adams and Yamamoto's methods have given good results with minor deviations.View full abstractDownload PDF (1146K) -
Akira MURATA, Toshitaka OMAE, Tetsuo SUZUKI1980 Volume 29 Issue 11 Pages 780-785
Published: November 05, 1980
Released on J-STAGE: February 16, 2010
JOURNAL FREE ACCESSFluorescent reaction of, antimony (III) with 3-hydroxyflavone and its twelve hydroxyl and methoxyl derivatives was studied. All these reagents react with antimony (III) to form the soluble complexes, which show strong fluorescence in perchloric or sulfuric acid, weak fluorescence in phosphoric acid and no fluorescence in hydrochloric acid. The insertion of hydroxyl or methoxyl group into the 2'-, 3'-, or 5-position of 3-hydroxyflavone decreases the fluorescence intensity, whereas the insertion of these groups into the 4'- or 7-position greatly increases the intensity. The recommended acid and reagent for the fluorometric determination of antimony (III) are perchloric acid and 3, 7-dihydroxyflavone, respectively, and the complex has a maximum excitation at 395 nm and emission at 456 nm in 1 M perchloric acid. Analytical procedure is as follows: To a solution containing (0.12.0)μg of antimony (III), 2.5 ml of methanolic 1×10-3 M solution of reagent, 10 ml of methanol (the final content is 50 vol %) and 5 ml of 5 M perchloric acid are added, and the mixture is diluted to 25 ml with water. The fluorescence of longer wavelength than 430 nm is measured exciting at 405 nm by mercury line against 1 μg/ml aqueous solution of sodium fluorescein. The analytical curve is linear in the range above-mentioned. The coefficient of the variation obtained in five measurements was 1.1% for 1.22 μg of antimony (III). The molar ratio of antimony (III) to reagent in the complex is 1:1. In the determination of 1.50 μg of antimony (III), sulfate, nitrate, phosphate and acetate (up to 100 mg), EDTA, chloride, oxalate, tartrate and citrate (1 mg), Be, Mg, Ca, Sr, Ba, Cu, Ag, Zn, Cd, Pb and As(III, V) (10mg), Cr (III), Ni, Co and Pd (1 mg), Au, Tl(III), Ti, V and W (100μg), Hg (II), Al, In, Bi, Nb and Fe (III) (10μg) do not interfere with the determination, but Sn (IV), Zr, Hf, Ga and Ge give positive errors to a large extent.View full abstractDownload PDF (917K) -
Kenjiro HAYASHI, Yoshiaki SASAKI, Shoji TAGASHIRA, Naoko IKUTA1980 Volume 29 Issue 11 Pages 785-790
Published: November 05, 1980
Released on J-STAGE: February 16, 2010
JOURNAL FREE ACCESSBismuth (III) ion reacts with thiourea to form yellow water-soluble complex in an acidic solution. This complex can be extracted into methyl isobutyl ketone (MIBK) or ethyl acetate as an ion pair with perchlorate ion. The extracted species gave an absorption maximum at 472 nm in each solvent, and the molar absorption coefficients at 472 nm were 1.04×104 (in MIBK) and 1.07×104 cm-1 mol-1 dm3 (in ethyl acetate). The effect of the concentrations of perchlorate ion and thiourea on the distribution ratio of bismuth was investigated, and it was concluded that the composition of the extracted species was [Bi (thiourea)2] (ClO4)3. The conditional formation constant of bismuth-thiourea complex, the ion association constant between the complex and perchlorate ion, and the distribution constant of the extracted species were determined at the ionic strength of 3.60 mol dm-3 at 25°C. The respective values obtained in MIBK extraction system were 3.0×10, 0.085 and 6.0, and those in ethyl acetate extraction system were 5.2×10, 0.028 and 7.9, respectively. The reaction among bismuth (III) ion, thiourea and perchlorate ion in aqueous solution was then investigated spectrophotometrically at the ionic strength of 3.60 mol dm-3. Two species, [Bi (thiourea)2] and [Bi(thiourea)2]-(ClO4)3, were formed, and their molar absorption coefficients at 468 nm (absorption maximum wavelength) were 6.0×103 and 8.4×103cm-1 mol-1 dm3, respectively. The constants obtained at 24.2°C for the complex formation and ion association were 3.2×10 and 0.14, respectively. In addition, the ΔH and ΔS values obtained for the complex formation were -19 and -35, respectively, and those for the ion association were -7.7 kJ mol-1 and -45 J mol-1 K-1, respectively.View full abstractDownload PDF (1001K) -
Tetsu KUMAGAI, Katsuya UESUGI1980 Volume 29 Issue 11 Pages 791-795
Published: November 05, 1980
Released on J-STAGE: February 16, 2010
JOURNAL FREE ACCESSA method for the gravimetric determination of palladium with 2-hydroxy-1-naphthaldoxime (HNA) has been studied. Palladium is quantitatively precipitated from fairly acidic solution as a sparingly soluble complex with HNA. The precipitate dried at 110°C is confirmed to be Pd (HNA)2 by elemental analysis and the gravimetric factor for palladium is 0.2222. The recommended procedure is as follows: Thirty five ml of 0.5 % HNA in methanol is added to 15 ml of a sample solution containing (525) mg of palladium and acidified with hydrochloric acid to (0.51.5)N. The solution is allowed to stand for 1 h with stirring at room temperature. The yellow precipitate thus obtained is filtered off on a G-4 sintered glass crucible, washed first with a mixture of hydrochloric acid (0.2 N) and methanol (70%) and then with methanol to remove the excess reagent, and dried at 110°C to constant weight. The method can successfully be applied to the determination of palladium in brazing filler metal.View full abstractDownload PDF (476K) -
Analytical studies of metals on gas phase. XIIITaitiro FUJINAGA, Tooru KUWAMOTO, Kenji SUGIURA, Shigekazu ICHIKI, Nor ...1980 Volume 29 Issue 11 Pages 796-799
Published: November 05, 1980
Released on J-STAGE: February 16, 2010
JOURNAL FREE ACCESSThermogravimetric analysis of 24 metal-trifluoroacetylacetone (TFA) chelates was investigated in the atmospheres of helium and of helium containing TFA vapor by using the injection chamber of a gas chromatograph equipped with a ligand vapor generator. The TGA curves showed that these metal-TFA chelates can be classified into three categories as follows: (1) Metal-TFA chelates, including Be2+, Al3+, Sc3+, V3+, VO2+, Cr3+, Mn3+, Fe3+, Co3+, Cu2+, Ga3+, Zr4+ and In3+, are completely vaporized and the TGA curves obtained in both atmospheres overlap with each other. (2) Metal-TFA chelates, including Mn2+, Co2+, Ni2+, Zn2+ and Lu3+, are completely vaporized in helium containing TFA vapor but thermally decomposed in helium alone. (3) Metal-TFA chelates, including La3+, Ce3+, Pr3+, Nd3+, Sm3+ and Eu3+, are incompletely vaporized with thermal decomposition in both atmospheres.View full abstractDownload PDF (636K) -
Analytical studies of metals on gas phase. XIVTaitiro FUJINAGA, Tooru KUWAMOTO, Yasuo NAKAMURA, Norio MATSUBARA1980 Volume 29 Issue 11 Pages 799-801
Published: November 05, 1980
Released on J-STAGE: June 30, 2009
JOURNAL FREE ACCESSFor the purification of Be2+-, Al3+-, Sc3+-, V3+-, VO2+-, Cr3+-, Mn3+-, Fe3+-, Co3+-, Co2+-, Ni2+-, Zn2+-, Zr4+- and In3+-trifluoroacetylacetonates, a new sublimation method was investigated in the flow of helium containing the vapor of trifluoroacetylacetone under atmospheric pressure. An entrainer sublimator equipped with a ligand vapor generator was used. From the results of elemental analysis and the measurements of melting point, it was realized that the proposed method gave satisfactorily purified samples without any associated thermal decomposition.View full abstractDownload PDF (477K) -
Hiroshi MATSUO, Takahiro KUMAMARU, Shigeki HARA1980 Volume 29 Issue 11 Pages 801-804
Published: November 05, 1980
Released on J-STAGE: June 30, 2009
JOURNAL FREE ACCESSA solvent extraction system with Zephiramine-thiocyanatopyridinenickel (II) -chloroform was investigated for the use of a pretreatment procedure in a graphite furnace atomic-absorption spectrometric determination of nickel. In contrast to cobalt (II), Zephiramine-thiocyanatonickel (II) could not be extracted into chloroform without pyridine in the aqueous phase. When the aqueous/organic phase volume ratio was 25 ml/5 ml, the best extraction of nickel was observed in the pH range of 5.111.8, provided that the concentrations of Zephiramine, potassium thiocyanate and pyridine were kept at 4.0×10-3 M, 5.0×10-2 M and 0.16 %, respectively. As for the measurement of atomic-absorption, the organic extract (20 μl) was injected into a graphite furnace and then dried (200°C-30 s), ashed (930°C-60 s) and atomized (2900°C-10 s) with an argon flow rate of 3 l/min. The linearity of the absorbance (232.0 nm nickel line) vs. the concentration of nickel was good up to 3 μg of nickel in the aqueous phase. The coefficient of variation obtained from 10 runs was 2.0 % for the determination of 3.0μg of nickel. Numerous cations and anions gave no interfering effect even when present in 1000-fold amounts (by weight) over nickel. This method was applied to the analysis of waste water from a plating factory.View full abstractDownload PDF (652K) -
Toshio MATSUDA, Shinichi ITO, Toyoshi NAGAI1980 Volume 29 Issue 11 Pages 804-806
Published: November 05, 1980
Released on J-STAGE: June 30, 2009
JOURNAL FREE ACCESSThe amperometric titration of formaldehyde in alkaline solutions with diethylenetriamine (dien) was studied. The polarographic reduction current of formaldehyde diminished rapidly with addition of dien, and reached the equilibrium within a few minutes. The decrement of the limiting current was proportional to the concentration of dien added. At pH between 12.513.3, the end point was obtained within ±2.0 % error to the value calculated as 2:1 in molar ratio of HCHO to dien. The procedure is as follows: After 50 ml of a supporting electrolyte solution containing 0.1 M KCl and 0.1 M NaOH has been deoxygenated in the cell, 5.000 ml of a formaldehyde solution of an appropriate concentration was delivered by a microburet and deoxygenated. After each addition of titrant, the solution was mixed by passing nitrogen gas for 2 min, and then the current at a potential of -1.80 V vs. SCE was measured. A normal L-shaped titration curve was obtained. Formaldehyde solution {(0.10.05) M} could be determined within the relative error of ±2.0 % and within the relative standard deviation of 0.4 %.View full abstractDownload PDF (471K) -
Hitoshi HOSHINO, Takao YOTSUYANAGI1980 Volume 29 Issue 11 Pages 807-808
Published: November 05, 1980
Released on J-STAGE: June 30, 2009
JOURNAL FREE ACCESSLiquid chromatographic separation of 8-quinolinolatoaluminum (III) chelate was established by the reversed-phase partition system. In the presence of diethyldithiocarbamate (DDTC) as a masking agent, 8-quinolinolatoaluminum (III) chelate was selectively separated from other metal chelates on a Yanapak ODS column (4 mm×250 mm) using 72 wt % aqueous methanol containing 10-2 mol/kg of sodium acetate as a mobile phase at a flow rate of 1 cm3/min. Metal chelates in the aqueous sample solution were solubilized with nonionic surfactant of Triton X- 100 (0.56 wt %). Aluminum ion of (0.12.4)×10-5mol/kg level can be determined with the peak height calibration curve obtained at 370 nm using 0.04 absorbance unit full-scale. At least a 50-fold molar excess of iron did not interfere with the determination. DDTC chelates of cobalt (II), nickel (II), copper (II) and vanadium (V) were base-line resolved under the same chromatographic conditions.View full abstractDownload PDF (241K) -
Kensaku HARAGUCHI, Koichi NAKAGAWA, Toshio OGATA, Saburo ITO1980 Volume 29 Issue 11 Pages 809-810
Published: November 05, 1980
Released on J-STAGE: June 30, 2009
JOURNAL FREE ACCESSThis method of simultaneous determination of traces of Mn and Zn, based on the difference of the rate of ligand substitution reaction between 1-(2-thiazolylazo)-2-naphthol (TAN) chelates and EDTA, is simple and free of interferences from other metal ions and anions. The procedure is as follows; place a sample solution containing (0.042.5)μg of Mn and Zn in a 50 cm3 volumetric flask, add 20 mg of N-(dithio-carboxy)-glycine to mask Cd, Cu and Hg and 2 cm3 of 2.0×10-3 mol dm-3 TAN solution (10 % Triton X-100), adjust the pH to 8.9 with 5 cm3 of Kolthoff's buffer solution and then dilute to the mark with water. The reaction is initiated by mixing this solution with 2.0×10-3 mol dm-3 EDTA solution (0.4 % Triton X-100, pH 8.9) at 25 °C using a stopped-flow apparatus. The reaction is run ten times and the signals of these runs are accumulated to improve the S/N. From the resultant curve Mn and Zn are determined graphically. The method can be applied to the determination of Mn and Zn in tap water.View full abstractDownload PDF (331K) -
Yusaku NOGAMI, Mitsuru FUJIMURA, Hirokazu MORII, Yoshikazu HASHIMOTO1980 Volume 29 Issue 11 Pages T85-T90
Published: November 05, 1980
Released on J-STAGE: February 16, 2010
JOURNAL FREE ACCESSFilter cake standards were prepared for X-ray fluorescence analysis of heavy metals in aerosol samples. Various amounts of elements, Fe, Mn, Zn, Pb, Cu and Ni corresponding to the concentrations of these elements in the aerosol samples were coprecipitated by diethyldithiocarbamate (DDTC) with Co as a carrier and collected on a membrane filter to make the thin cakes. Optimum conditions for preparation of the filter cakes are as follows : 20 ml of 0.2 % DDTC solution was added to metal solutions of pH 78 and the produced precipitate was aged at room temperature for 40 min. Recovery of each element was above 95 %. Linearity of calibration curves was excellent in the range of the content of each element in the aerosol samples. The calibration curves have not changed for 10 months and the coefficients of variation of X-ray intensities of the elements were less than 2 % for measurements under 8 different dates during this period. Similar results were obtained by using quartz fiber filters, which were most suitable to collect atmospheric aerosols. Analytical results of urban aerosol samples by this method agreed well within 10 % error with those by atomic absorption spectrometry. The proposed method is practically profitable for monitoring of air pollutions.View full abstractDownload PDF (994K) -
Kazuo KUGA1980 Volume 29 Issue 11 Pages T90-T94
Published: November 05, 1980
Released on J-STAGE: February 16, 2010
JOURNAL FREE ACCESSDetermination of trace amounts of vanadium by solvent extraction-graphite furnace atomic absorption spectrometry has been studied. In order to avoid the interferences from other elements encountered in practical analysis, vanadium sample solutions were prepared by N-benzoyl-N-phenylhydroxylamine (BPA)-solvent extraction method. When using the organic solvent as as ample solution, the effect of soaking and diffusion of the solution is known to be serious. To overcome these problems, the following improvements were made. (1) To overcome the diffusion of the solution on the surface of the tube, 5 grooves were made on the inner surface at the position of 5 mm from the both ends of the tube. (2) To overcome the soaking of the solution into the inside of the tube, the optimal coating conditions of pyrolitic graphite (P. G.) were established for each solvent. The graphite tube was made from the Nippon Carbon Corp. FG-303, FG-36H (density: 1.8). The P. G. coating were made in argon atmosphere containing 10 % volume of methane by heating up to 2200°C. The optimal P. G. coating time was 3 min for benzene and toluene and 4 min for chloroform and carbon tetrachloride. When the present tube and the BPA-toluene system was used, the detection limit (S/N =2) of vanadium was 0.05 ng. The propose method was applied to the determination of vanadium in iron and steel.The standard deviations obtained with the present tube were (3.14.8)%, compared to (5.711.2) % with the conventional uncoated tube.View full abstractDownload PDF (773K)
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