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Volume 49, Issue 5
Displaying 1-9 of 9 articles from this issue
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Review
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Setsuko YAJIMA, Keiichi KIMURA2000 Volume 49 Issue 5 Pages 279-296
Published: 2000
Released on J-STAGE: June 29, 2001
JOURNAL FREE ACCESSIon sensors include electrochemical sensors to detect analyte ions electrochemically, i.e., membrane-potential sensors, such as ion-selective electrodes;voltammetric sensors, such as chemically-modified electrodes;and optical sensors to detect them spectrophotometrically, i.e., optodes or optrodes.There has been much information reported so far on ion sensors from two types of research, viz., the development of new sensors and basic studies about the response mechanism of ion sensors.The present review is concerned mainly with research topics of our intered, which include potentiometric anion sensors based on new neutral carriers and metal complexes, biocompatible ion sensors for the continuous detection of analyte ions in biological samples, and optodes for detecting electrically neutral molecules.View full abstractDownload PDF (1294K)
Research Papers
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Hideo ASAKURA, Katsushige IKEGAMI, Yasujiro YAMADA, Hisanobu WAKITA2000 Volume 49 Issue 5 Pages 297-306
Published: 2000
Released on J-STAGE: June 29, 2001
JOURNAL FREE ACCESSThe chemical components in refractories containing silicon carbide were determined by an X-ray fluorescence analysis using glass beads.Good-quality glass beads can be prepared by the following method.After 0.3000g of a silicon carbide sample is mixed with 3.0000g of flux(Li2B4O7), the mixture is placed in a Pt-Au alloy dish.It is then fused in a furnace under an O2 atmosphere at 840°C for 33 hours, and finally fused at 1150°C.Since the mass of the resulting glass bead is increased by the oxidation of SiC, which produces SiO2 during sample heating, the ratio of 10:1 between the flux and the sample is changed.For this reason, the popular JIS method of using SiO2-Al2O3 binary calibration curves could not be applied to obtain an accurate analysis with these glass beads.We therefore developed a new calibration method.In this method, the gain on ignition(GOI) is regarded as being a component in the sample, and the theoretical matrix correction coefficients(dj) of each component are calculated by the fundamental parameter procedure(FP procedure) using the GOI as a base component.The GOI-SiO2 binary calibration curves(GOI correction curves) are made with the djs obtained by the FP procedure.With this method the standard deviation(SD) of the GOI correction curves is very satisfactory.Our test results include an SD of 0.24mass% for SiO2 and 0.096mass% for Al2O3.The GOI correction curves are applicable to all components in the reference materials, except for Fe2O3.View full abstractDownload PDF (715K) -
Masaru MITSUSHIO, Toshifumi YOSHIDOME, Satsuo KAMATA2000 Volume 49 Issue 5 Pages 307-311
Published: 2000
Released on J-STAGE: June 29, 2001
JOURNAL FREE ACCESSThe concentrations of carboxylic acid esters and lubricants were measured by using a goldcoated optical-fiber sensor system.The sensor system consisted of a He-Ne laser, an optical fiber, and a detector.A part of the optical fiber, which was in contact with a sample solution, was coated by a gold thin film after removing the fiber clad.The intensity of the transmitted laser light by the fiber varied with the refractive index of the sample solution.The transmittance of the fiber on ethyl formate with a refractive index below 1.37 decreased with increasing the concentration of the formate, while that of the fiber on the other ester compounds with a refractive index, above 1.37, such as diethyl sebacate and DOS, increased with increasing these material concentrations.The difference in the concentration dependence of the transmittance was thought to be explained on the basis of the refractive index of the sample solution.The sensitivity of this sensor system was good for these carboxylic acid esters and lubricants.In particular, plots of the transmittance against the concentrations of DOS and DOA were liner over the range of 20 to 80%.Thus, this gold-coated optical fiber sensor system can be used to determine the concentration of carboxylic acid esters and lubricants.View full abstractDownload PDF (304K) -
Akiyo OTSUKA, Yasushi ISHIHAMA, Kiyohiko UCHIKAWA, Naoki ASAKAWA2000 Volume 49 Issue 5 Pages 313-317
Published: 2000
Released on J-STAGE: June 29, 2001
JOURNAL FREE ACCESSWe developed an N-shaped partition cell to measure the logarithm of partition coefficients between 1-octanol and water(log Pow).The cell enabled us to measure the concentrations of the solute in the two phases periodically by HPLC without any tedious or time-consuming steps.The equilibrium time in the cell was almost 4 hours, and the obtained log Pow values were consistent with those by the conventional shake-flask method for neutral compounds with 1.1<log Pow<3.8.This approach was applied to a monovalent basic drug, verapamil, and the dependence of log Pow on the pH was measured using six cells simultaneously.The obtained pKa and log Pow values of verapamil by the N-shaped cell method were in agreement with those by the shake-flask method;the analysis time was alsomst 7 hours.The cell was used in an HPLC autosampler, and the whole operation for measuring log Pow was performed automatically in combination with HPLC.View full abstractDownload PDF (326K)
Technical Papers
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Shigeru TERASHIMA, Noboru IMAI, Mamoru TOMINAGA, Shizuko HIRATA, Masah ...2000 Volume 49 Issue 5 Pages 319-324
Published: 2000
Released on J-STAGE: June 29, 2001
JOURNAL FREE ACCESSIn order to provide a soil reference material which contains known chemical forms of miner and trace elements, thirty-one reagent materials, mostly in oxides, were artificially added to a natural soil collected from the Kanto loam formation near Geological Survey of Japan(GSJ).The concentrations of added minor and trace elements were about 1000μg/g for As, Co, Cr, Cu, Mo, Ni, Pb, V, W, Y, Zn, and Zr, 100μg/g for B, Be, Bi, Br, Cd, Sb, Sn, and Ta, 10μg/g for Ag, Hg, I, In, Se, Te, and Tl, and 1μg/g for Au, Pd, Pt, and Rh, respectively.The ingredients were diluted with a small amount of feldspar powder and ground in an agate mortar, then diluted with the same feldspar powder sequentially and ground and mixed in an agate mortar or a small ball mill thoroughly at each dilution step.Finally, a mixture of about 12kg was diluted with 108kg of well-dried natural soil using a large ball mill.The sample was screened with a 246μm(60 mesh)opening of a stainless-steel sieve, and mixed well before packing in glass bottles.A homogeneity test showed that all of the elements studied were homogeneously distributed.Forty-three major, minor and trace elements were determined, and the results were tabulated together with the analytical methods and the outline of sample treatment procedures.Analytical results of the mineral composition by X-ray diffraction are also presented.View full abstractDownload PDF (406K) -
Yuichi KITASAKO, Tohru NIKAIDO, Junji TAGAMI, Kenichi IKEDA, Kyoko MIT ...2000 Volume 49 Issue 5 Pages 325-327
Published: 2000
Released on J-STAGE: June 29, 2001
JOURNAL FREE ACCESSThe aim of this study was to investigate the surface analysis of human teeth using a pH-imaging microscope based on a semiconductor silicon sensor.Disks were cut from freshly extracted non-carious and carious human teeth.Samples were placed on an agar film to evaluate the surface pH distribution.Non-carious samples were treated with 37% phosphoric acid and then thoroughly rinsed.A reduction of the pH value was clearly detected after a phosphoric aicd treatment.The pH distribution of carious lesions was lower than that of non-carious lesions.From these results, this pH-imaging technology has the potential to aid in carious assessments and carious treatments.View full abstractDownload PDF (227K) -
Sadao NAKAMURA, Masahiko TAKINO, Shigeki DAISHIMA2000 Volume 49 Issue 5 Pages 329-336
Published: 2000
Released on J-STAGE: June 29, 2001
JOURNAL FREE ACCESSAn analytical method for the determination of potential endocrine disruptors, seven alkylphenols including nonylphenol and 4-t-octylphenol, by gas chromatography/mass spectrometry(GC/MS)with negative-ion chemical-ionization(NICI)has been developed.First, the detection limits by GC/MS-SIM with electron ionization(EI)and NICI were compared for the underivatized and pentafluorobenzyl(PFB)derivatives of alkylphenols.The NICI-SIM of PFB derivatives used an(M-PFB)- ion as the monitoring ion.The reagent gas(methane)flow rate and the ion-source temperature were determined to be 2.5ml/min and 250°C, respectively, for the optimized NICI-SIM conditions.In the case of EI-SIM, the sensitivities of PFB derivatives were 2.1∼6.3 times higher than those of underivatized target chemicals.Furthermore, the sensitivities of PFB derivatives by NICI-SIM were 67∼300 times higher than those of underivatized target chemicals by EI-SIM.The detection limits by NICI-SIM ranged from 1.0pg/ml to 33pg/ml.This method also provides good linearity of the calibration curve and repeatability.The correlation coefficients of calibration curve were >0.9995 for all chemicals in the concentration range from 1pg/ml to 10ng/ml.The relative standard deviations of the peak areas of the target chemicals were 3.6∼6.8% for 10pg/ml, 2.3∼4.9% for 100pg/ml and 2.4∼3.5% for 1000pg/ml.The recoveries of the target chemicals from a river-water sample spiked with standards at 10pg/ml levels for 4-n-pentylphenol, 4-n-hexylphenol, 4-n-heptylphenol and 4-n-octylphenol, 100pg/ml levels for 4-t-butylphenol and 4-t-octylphenol and 5000pg/ml levels for nonylphenol were 77.9∼102%.The relative standard deviations were to be from 4.1 to 12%.View full abstractDownload PDF (446K) -
Hisomu NAGASHIMA, Toshimitu OKAMOTO, Yoshimi DEWA, Takatoshi HATTORI2000 Volume 49 Issue 5 Pages 337-343
Published: 2000
Released on J-STAGE: June 29, 2001
JOURNAL FREE ACCESSA method for elemental micro-analysis that employs a novel coupled combustion/ion chromatography(IC)apparatus is described in detail.A sample of 1.0∼2.5mg was weighed and ignited instantaneously in quartz combustion tube at 950°C with a carrier gas comprising oxygen and helium(6:4)at a flow rate of 30ml/min.The combustion products were collected in 50ml(total volume)of 0.5% hydrogen peroxide/2mM sodium hydroxide solution, containing a certain amount of phosphate ion as an internal standard(ISD).After a 50μl aliquot of each sample solution was injected into a suppressed conductivity ion chromatography system, a 1.8mM sodium carbonate/1.7mM sodium hydrogen carbonate solution was eluted under the following operating condition:flow rate, 1.5ml/min;column temperature, 30°C;scavenger, 15mM sulfuric acid.The calibration curves obtained from the peak areas of the anions(F-, Cl-, Br- and SO42-)is linear with high correlation coefficients of more than 0.999 and a good relative standard deviation(RSD, %)of 0.2∼0.4% for 10 repeated measurements.The simultaneous determination of fluorine, chlorine, bromine and sulfur in organic compounds was achieved by incorporating this combustion/IC technique.The thus-obtained analytical values are in good agreement, within ±0.3% of the theoretical values for the several compounds tested.View full abstractDownload PDF (398K)
Notes
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Tatsuhiko TANAKA, Toru SATO2000 Volume 49 Issue 5 Pages 345-348
Published: 2000
Released on J-STAGE: June 29, 2001
JOURNAL FREE ACCESSAn simple and precise method is described for the determination of arsenic in fluorspar by differential pulse anodic stripping voltammetry without any pretreatment steps using harmful chemicals.Arsenic(V)was reduced to arsenic(III)with potassium iodide.The arsenic(III)in an acidic solution was electrodeposited on a rotating gold-film electrode at −0.45V vs.SCE for 180s, and then a stripping voltammogram was recorded by a positive-going scan at a rate of 40mVs-1 to 0.2V vs.SCE.The calibration{peak height vs.arsenic(III)concentration}curve was linear over the range(1.3∼4.0)×10-7M arsenic(III) and passed through the origin.The detection limit(3σ)was 1.98×10-8M.Copper(II), lead(II), and antimony(III)interfered with the arsenic(III)determination severely.The determination of 10.6μg g-1 of arsenic in fluorspar was achieved with an RSD(n=5)of 3.4% within 3h.The proposed method is an improvement over the existing JIS method.View full abstractDownload PDF (209K)
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