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Volume 45, Issue 7
Displaying 1-12 of 12 articles from this issue
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Koji TOHDA1996 Volume 45 Issue 7 Pages 641-657
Published: July 05, 1996
Released on J-STAGE: May 29, 2009
JOURNAL FREE ACCESSIon-selective charge separation at the surface of ionophore-incorporated liquid membranes was studied by observing optical second harmonic generation (SHG) and by using lipophilic photoresponsive ionophores as a molecular probe. It was found that SHG signals from the ionophore-incorporated membranes in contact with aqueous primary cation chloride solutions generally increased with increasing cation concentration and then leveled off. This can be explained by the formation of oriented and therefore SHG active cation-ionophore complexes at the membrane surface. It was found that the membrane potential and SHG signal changed in parallel. This result suggests that the observed membrane potentials were primarily governed by SHG active oriented cation complexes at the membrane surface. To further clarify the influence of the surface charge density on the phase boundary potential, photoresponsive ionophores were used as a molecular probe because the ratio of the ionophore conformers with different complexation affinities is controlled quantitatively by light irradiation without any change in the membrane composition. The photoinduced changes in the potentiometric responses were analyzed as a function of the surface charge density by using a surface model based on a double-diffuse layer. As a result, it was found that the photoinduced changes in the potentiometric response behaviors, even when the deviations from a Nernstian response were observed, are in good agreement with the values calculated on the basis of the proposed model. This agreement leads to the important conclusion that the sub-Nernstian response slope is attributed to the low surface charge density due to lower ionophore concentrations.View full abstractDownload PDF (2915K) -
Kei TODA, Isao SANEMASA, Toshio DEGUCHI1996 Volume 45 Issue 7 Pages 659-665
Published: July 05, 1996
Released on J-STAGE: January 15, 2010
JOURNAL FREE ACCESSThe existence of intermediate species during complex formation between metal ions and porphyrin in aqueous solution was confirmed using an Amberlite XAD-2 resin column. When porphyrin solution is injected into the metal ion solution stream, the porphyrin adsorbed to the XAD column with the metal ions associated or complexed with it, and the decrease of the metal ion in solution is observed in the column eluant. Calculated from the decrease, the association constants of Cu2+ and Zn2+ with α, β, γ, δ-tetrakis(4-N-methylpyridyl)porphine (TMPyP) are 32 (10°C) and 57 M-1 (25°C), respectively. It was also confirmed that the intermediate exists before the metal replacement reaction between Cu2+ and the metalloporphyrin complex. The association constant in the Cu2+/Zn-TMPyP system was especially large. As mentioned above, the interaction of the metal ion and the ligand before complex formation can be investigated by separating the ligand with the attached metal ion from the free metal ion using the hydrophobic interaction between the column and the ligand. These results were in good agreement with the values obtained by the kinetic method.View full abstractDownload PDF (983K) -
Masahito SUGIYAMA1996 Volume 45 Issue 7 Pages 667-675
Published: July 05, 1996
Released on J-STAGE: May 29, 2009
JOURNAL FREE ACCESSSimultaneous analysis of major and minor elements in aquatic suspended particulate matter was investigated. The sample and the Nuclepore filter, which was used to collect suspended particulate matter, were transferred into a Teflon screw vial and mixed with aqueous ammonia. After standing, the mixture was dried, then digested with a mixed solution of perchloric, nitric and hydrofluoric acids. After drying, perchloric and nitric acids were added to the residue, and the mixture was heated to dryness. The residue was dissolved in dilute nitric acid. The solution was analyzed with inductively coupled plasma atomic emission spectrometer. Four standard reference materials were analyzed by this method. The results agreed well with the respective reference values for fourteen elements (Al, Ba, Ca, Cr, Cu, Fe, Mg, Mn, Ni, P, Sr, Ti, V and Zn). Analytical data for K and Na, which were determined with an atomic absorption spectrometer, were also in good correspondence to the reference values. The present method is applicable also to other environmental samples such as sediment, rock, living organisms and aerosols.View full abstractDownload PDF (1483K) -
Keiichi FUJIMORI, Masaru KITANO, Norimichi TAKENAKA, Hiroshi BANDOW, Y ...1996 Volume 45 Issue 7 Pages 677-682
Published: July 05, 1996
Released on J-STAGE: January 15, 2010
JOURNAL FREE ACCESSRecently, methanol has attracted attention as a clean alternative fuel. However, methanol is toxic and the formaldehyde formed during incomplete combustion is even more toxic. Therefore, the development of an accurate determination method for methanol in the environment is very important. However, it is difficult to analyze trace amounts of methanol in solution, especially in a sample solution containing formaldehyde. In the present method, methanol was oxidized to formaldehyde with alcohol oxidase (EC 1.1.3.13, AO), and the formaldehyde produced was determined by colorimetry. The sample containing methanol and formaldehyde was bubbled with 100% oxygen for 15 min at a flow rate of 8.5l/min. An aliquot of the sample was mixed with 0.1 ml of phosphate buffer solution (pH 7.5, 1/15 M) and 0.25 unit AO, and was allowed to stand at 25°C for 15 minutes. Formaldehyde was determined by colorimetry with AHMT (4-amino-3-hydrazino-5-mercapto-1, 2, 4-triazole). In this manner, total concentrations of formaldehyde and methanol could be determined. On the other hand, only formaldehyde concentration could be determined without AO. Thus, the methanol concentration could be calculated from the difference between these two concentrations. The detection limit of the present method for methanol was 2.08 μM, which was 14 times as sensitive as conventional colorimetry.View full abstractDownload PDF (937K) -
Miho TANAKA1996 Volume 45 Issue 7 Pages 683-687
Published: July 05, 1996
Released on J-STAGE: May 29, 2009
JOURNAL FREE ACCESSDissolution rate of silica gel with alkali, alkali-earth, and zinc chloride solution was examined. The dissolution rate depends on the concentration of the cation in solution. In each series, the larger the ionic radius, the higher is the dissolution rate. In solutions containing alkali cations, a high charge density prevents the hydrolysis of the Si-O bond because the water molecules cannot move freely. On the other hand, the dissolution rates of the silica gel in Ca and Sr chloride solutions are very high. The rates in alkaline-earth and zinc chloride solutions vary over a wider range than that for the alkali chloride solutions. This suggests that the mechanism of dissolution of silica gel in Ca and Sr chloride solutions is different from that in Mg, Zn and alkaline chloride solutions.View full abstractDownload PDF (850K) -
Hiroki OHURA, Toshihiko IMATO, Sumio YAMASAKI1996 Volume 45 Issue 7 Pages 689-695
Published: July 05, 1996
Released on J-STAGE: May 29, 2009
JOURNAL FREE ACCESSA simple and rapid potentiometric FIA method for the determination of trace hydrazine is developed, using a combination of a Ce(IV)-Ce(III) potential buffer solution and a flow-through type redox detector. The method is based on the measurement of the transient potential change from the equilibrium potential governed by the Ce(IV)/Ce(III) couple in the potential buffer to the lower potential governed by the N2H5+/N2 couple, which was estimated by spectrophotometric and potentiometric batch experiments. In the present method, the sample (200 μl) is injected into a water carrier stream and merged with the potential buffer stream consisting of acidic Ce(IV)-Ce(III). The concentration of hydrazine is determined by measuring the potential change with the potentiometric detector constructed with a Pt-electrode and an Ag/AgCl reference electrode. Hydrazine in a wide range from 10-7 M to 10-3 M can be determined by selecting the concentration of potential buffer solution from 10-4 M to 10-2 M. The linear relationship between peak heights and concentrations of hydrazine from 5×10-7 M to 5×10-6 M and the lower detection limit of 1×10-7 M (3.2 ppb) were obtained when a 2 X 10-4 M Ce(IV)-Ce(III) buffer was used. The relative standard deviation was 0.9% (n=6) for analysis of 5×10-6 M hydrazine at sampling rates of 40 h-1. The present method was applied to the determination of hydrazine in real boiler water, and was found to provide a good recovery for boiler water containing hydrazine at the 10 ppb level.View full abstractDownload PDF (1076K) -
Toshio TAKAYANAGI, Yasuko HIROI, Shoji MOTOMIZU1996 Volume 45 Issue 7 Pages 697-699
Published: July 05, 1996
Released on J-STAGE: May 29, 2009
JOURNAL FREE ACCESSStacking effect of sulfate ion on the analysis of inorganic anions by capillary zone electrophoresis was examined during the sample injection period. A used silica capillary was dynamically coated with tetradecyltrimethylammonium bromide (TDTMA+Br-) to control the electroosmotic flow. Analyte anions were directly detected by photometry at 214 nm. Five kinds of anions, namely bromide, nitrite, nitrate, molybdate, and tungstate, were detected. Anion separation was developed using 4×10-3 M sodium sulfate in the carrier solution. Peak heights for anions increased along with additional Na2SO4. The stacking effect was more effective for the anions with high mobility than those with low mobility. Calibration graphs for nitrate and nitrite showed good linearity in the concentration range of 10-6 to 10-5 M.View full abstractDownload PDF (403K) -
Yuko NISHIMOTO, Yuko MORISHITA, Mihoko KAITSUKA1996 Volume 45 Issue 7 Pages 701-706
Published: July 05, 1996
Released on J-STAGE: May 29, 2009
JOURNAL FREE ACCESSAn electrolyzed strong acid aqueous solution is called function water, because of its strong bactericidal activity and effects on viruses, the immune system and atopic dermatitis. As function water can be prepared easily in a hospital, it was introduced for use in the medical field. Function water has unique characteristics such as a high positive oxidation-reduction potential, strong acidity and a high concentration of dissolved oxygen. But a detailed analytical study has not been done. In the present investigation, the pH measurements, ORP measurements and DO measurements were carried out, and the concentrations of Na, K, Cl- and residual chlorine in the solutions were measured. We examined the effects of electric current and electrolysis promoting reagent. Using analytical results, a strong acid aqueous solution was prepared without electrolysis. The characteristics of the electrolyzed solution were compared with those of the prepared solution. Most characteristics of the electrolyzed solution were explicable by its components.View full abstractDownload PDF (873K) -
Shogo SUZUKI, Shoji HIRAI1996 Volume 45 Issue 7 Pages 707-710
Published: July 05, 1996
Released on J-STAGE: May 25, 2010
JOURNAL FREE ACCESSMultielements in "Hiziki" reference material (NIES No. 14) prepared by the National Institute for Environmental Studies (NIES) were determined by instrumental neutron activation analysis (INAA). Ten portions of the samples (ca. 200-500 mg) were irradiated for 10 s at a thermal neutron flux of 1.5×1012 n cm-2 s-1 and 6 h at a thermal neutron flux of 3.7×1012 n cm-2 5-1 in the Rikkyo University Research Reactor. The irradiated samples were measured by conventional γ-ray spectrometry with a coaxial Ge detector and by anti-coincidence γ-ray spectrometry with a coaxial Ge detector and a well-type NaI(Tl) detector. Concentrations of 37 elements (Na, Mg, Al, S, Cl, K, Ca, Sc, Cr, Mn, Fe, Co, Ni, Zn, As, Se, Br, Rb, Sr, Ag, Cd, Sb, I, Cs, Ba, Ce, Eu, Tb, Yb, Lu, Hf, Ta, Au, Hg, Th, U) were determined with correction for interfering nuclear reactions.View full abstractDownload PDF (593K) -
Eiko NAKAMURA, Junko INOUE, Hiroshi NAMIKI1996 Volume 45 Issue 7 Pages 711-715
Published: July 05, 1996
Released on J-STAGE: May 29, 2009
JOURNAL FREE ACCESSDetermination of nitrite, nitrate and bromide ions in sea water was performed by ion chromatography using a high-capacity anion exchange column with a high concentration NaCl solution as the eluent. The interference from a large amount of chloride ion in the sample could be eliminated using the TSK gel-SAX (3.7 meq/g, 4.6 mm×50 mm) column and sodium chloride solution (0.5 M) as the eluent at 1.2 ml/min. Because sulfate was also easily eluted from the column, it did not interfered with either the separation or the determination of anions. The sample without any pretreatment is inserted into a micro-loop(100μl). Analyte anions are photometrically detected at 210 nm. The relative standard deviations for nitrite and nitrate in ten replicate measurements at 1 mg/l were 2.8 % and 1.6%, respectively. This method was applied to the determination of total nitrogen in sea water. The sample was digested with alkaline-peroxodisulfate and neutralized with HCl. Total nitrogen in the digested sample was determined as nitrate by this method. The results obtained were in good agreement with those obtained by the JIS method.View full abstractDownload PDF (608K) -
Toshimitsu OKAMOTO, Akinori ISOZAKI, Hisomu NAGASHIMA1996 Volume 45 Issue 7 Pages 717-721
Published: July 05, 1996
Released on J-STAGE: May 29, 2009
JOURNAL FREE ACCESSCeramic carbon columns, coated with dodecylbenzenesulfonic acid, have been used in the simultaneous determination of inorganic anions by ion chromatography. This paper describes a simple and highly sensitive method for determining iodine in food colors both by the direct injection method to analyze free iodide ion after the removal of color and by an oxygen-flask-combustion method for total iodine including iodine covalently bonded. In the direct injection method, 30 mg of a sample was dissolved in 10 ml of water and this sample solution was passed through a Toyopak IC-SP cartridge. In the oxygenflask-combustion method, 7 to 8 mg of a sample was burned in an oxygen-filled flask containing 20 ml of 2 mM NaOH and 100 μl of 5% NH2NH2 as absorbents and water added to make 100 ml. A 50-μl aliquot of the solution was injected into the ion chromatograph. The sample was chromatographed on a ceramic carbon column with 7.5 % acetonitrile containing 4 mM Na2CO3 and 1 mM tetrabutylammonium hydroxide, under the following operating conditions : flow rate, 1.0 ml/min; column temperature, 30°C ; scavenger, 12.5 mM H2SO4. The contents of free iodide ion and iodine (I2) in food red No. 3 and No. 105 of Japanese Standard Food Additives by the direct injection method were found to be lower than 0.33 and 0.006%, respectively. The amount of dye molecules from total iodine determined by the oxygen-flask-combustion method was in good agreement with that determined by the gravimetric method directed in JSFA.View full abstractDownload PDF (815K) -
Shigeaki YONEMORI1996 Volume 45 Issue 7 Pages 723-724
Published: July 05, 1996
Released on J-STAGE: May 29, 2009
JOURNAL FREE ACCESSAnalytical methods for fluorochemical engineering materials have been investigated using spectroscopic and other techniques. Since almost all fluorochemicals are chemically stable, nondestructive analytical methods such as nuclear magnetic resonance spectroscopy (NMR), Raman spectroscopy, and X-ray fluorescence spectroscopy (XRF) were mainly used. In some cases, the decomposition of the C-F bonds of fluoroorganic compounds to fluoride ion and derivatization to a volatile fluoride were examined to determine fluorine content. Analytical methods have been also studied to determine the structures and quantities for the main and side components of some typical organic and inorganic fluoromaterials such as tetrafluoroethylene copolymers and fluorine doped quartz glasses. Moreover, simple structural determination methods for fluoroorganic compounds such as freons (CFCs) were established using 13C-19F INEPT and 19F-19F COSY NMR where complex couplings are eliminated.View full abstractDownload PDF (364K)
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