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Volume 45, Issue 10
Displaying 1-13 of 13 articles from this issue
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Kunihiro WATANABE, Tuyoshi YAMASAKI, Masayuki ITAGAKI1996 Volume 45 Issue 10 Pages 897-902
Published: 1996
Released on J-STAGE: May 07, 2010
JOURNAL FREE ACCESSThe micellar enhanced chemiluminescence method using 1, 10-phenanthroline to determine small amounts of cobalt(II) was investigated by the flow injection method. The proposed flow system is comprised of three flow lines for cobalt(II), 1, 10-phenanthroline and hydrogen peroxide, respectively. The effects of cationic surfactant micelles with cetyltrimethylammonium bromide (CTAB), zephiramine (Zeph), cetylpyridium bromide (CPB), etc. upon the chemiluminescence (CL) determination of cobalt(II) are described. Among the examined cationic surfactants, CTAB provided the highest enhancement, with a CL intensity approximately 110 times higher than that in the absence of surfactant. The authors also investigated the mechanism of CL-enhancement by spectrophotometry and fluorometry. The role of the micelle was revealed through the 3D spectra of cobalt(II)-phenanthroline complex formation, that is, the micelle enhanced the rate of chelate reaction by concentrating Co ion as the anionic species. The formed cobalt(II) chelate was concentrated into micelles.As a result, the concentration of cobalt(II)chelate decreased to 67% in aqueous phase. The high fluorescence intensity of 3, 3'-diformy1-2, 2'-dipyridyl produced by the cobalt(II)-catalyzed oxidation of 1, 10-phenanthroline with hydrogen peroxide was measured. It was found that the intensity of the fluorescence was enhanced 1.4 times in the presence of CTAB. The limits for the determination of cobalt(II)were 5.0 ppb (20μl sample injection) and 1.0 ppb (continuous sample flow at a sample feed speed of 0.8 ml/min) under the optimum conditions.View full abstractDownload PDF (965K) -
Takaya TAKEI, Yoshinori SUGITANI, Chikara AMANO, Yuko NISHIMOTO1996 Volume 45 Issue 10 Pages 903-908
Published: 1996
Released on J-STAGE: January 15, 2010
JOURNAL FREE ACCESSA simple method for measuring dielectric properties of water-alcohol solutions for structural studies was proposed. The apparatus consists of three components : RF-generator, resonator with parallel planar electrodes, and detector. The resonators composed of a coaxial line and a couple of electrodes, generates characteristic resonance frequencies (fR) related to the relative dielectricity of the sample. Shifts of fR with change of temperature, alcohol concentration and the kind of alcohol have been measured for water-alcohol binary solutions. The value of fR was found to be proportional to the ethanol molar fraction (xE) at xE's more than 0.15, but remained constant at lower concentrations. This suggests that the structure of a binary solution changes at this concentration and the relative dielectric permittivity of the system is no longer affected by more alcohol added. This characteristic concentration agrees well with that obtained by the TDR method, as well as that by mass spectrometric measurements. From the measurements for alcohol-alcohol mixtures, a discontinuity of fR was found at a certain temperature for 1:1 methanol-2-propanol mixture.View full abstractDownload PDF (916K) -
Yukitoki MORITA, Masafumi YOSHIKAWA, Akinori ISOZAKI1996 Volume 45 Issue 10 Pages 909-914
Published: 1996
Released on J-STAGE: January 15, 2010
JOURNAL FREE ACCESSA simple method is investigated for direct determination of trace copper in water by graphite furnace AAS: the copper(II)-N, N-diethyldithiocarbamate (DDTC) complex is collected on a membrane filter, a portion of which is then directly transferred to a graphite furnace. The analytical procedure is as follows : 5ml of 2% diammonium hydrogen citrate and 2ml of 0.5% DDTC are added to a 250 ml sample solution (pH 9), containing less than 0.60ng/ml of copper(II). After about 10 min, copper(II)is quantitatively collected on a cellulose-acetate membrane filter (diam.: 17.2mm, pore size : 0.45μm)by suction filtration. For direct AAS determination, a small disc (diam.: 2.0mm)is removed from the membrane filter with a paper punch and introduced into a graphite furnace. The optimal thermal programs are as follows : drying at 160°C for 60 s, ashing at 600°C for 30 s, atomization at 2600°C for 5 s in argon gas atmosphere (flow rate 2.0l/min). The 324.8nm line was used to quantity copper by the peak-area method with deuterium lamp-background correction. The relative standard deviation [for the determination of 2.44ng/ml copper in spring water] was 4.0% for 6 replicate measurements.View full abstractDownload PDF (1118K) -
Ryo NISHINO, Takashi SAITO1996 Volume 45 Issue 10 Pages 915-920
Published: 1996
Released on J-STAGE: May 07, 2010
JOURNAL FREE ACCESSA new type of method for determining concentration of phenolic resin in accumulated particulate matter on roads by hydrothermal decomposition-gas chromatography (GC) with methylation was investigated.After extracting particulate matter samples with tetrahydrofuran in an ultrasonic wave generator, 9 μl of extract was encapsulated in a pyrex glass capsule of 18 mm length and 0.8 mm i.d.with 0.5 μl of tetramethyl ammonium hydroxide as the methylating agent. The capsule was put in a cup of ferromagnetic material having a curie point of 235°C, and hydrothermal decomposition with methylation was done for 9 sec using a curie-point pyrolyzer. The capsule, after the tip was chipped off, was put in a cup of ferromagnetic material having a curie-point of 445°C, and thermal desorption was done for 9 sec in a pyrolyzer. Hydrothermal desorped decompozates were analyzed by GC. A linear relation between the amount of anisole produced and the concentration of phenolic resin was obtained. Reproducibility of the produced amount of anisole was 3.6% at the relative standard deviation when 300 μg of phenolic resin was analyzed with 6 repeated measurements. The concentration of phenolic resin in accumulated particulate matter samples on roads was measured. As a result, phenolic resin of 120250 μg/g-dust was detected, and the concentration of asbestos estimated from the concentration of the phenolic resin particles was 0.044 to 0.092 wt%.View full abstractDownload PDF (853K) -
Nobumasa ARAI, Hiroaki MINAMISAWA, Shigeru SUZUKI, Tadao OKUTANI1996 Volume 45 Issue 10 Pages 921-926
Published: 1996
Released on J-STAGE: May 07, 2010
JOURNAL FREE ACCESSRuthenium is adsorbed on activated carbon impregnated with 2, 4, 6-tri-2-pyridyl-1, 3, 5-triazine (TPTZ-AC). A simple and rapid determination method for trace amounts of Ru by graphite furnace AAS using direct heating of Ru adsorbed TPTZ-AC was investigated.The proposed method is as follows. A sample solution of 1001000cm3 containing Ru is mixed with 50 mg of TPTZ-AC. The pH is then adjusted to 7.0 with phosphate buffer solution, and stirred for 10 min. The Ru adsorbed TPTZ-AC was separated from the sample solution by filtration. The TPTZ-AC on membrane filter is dispersed in 5.0cm3 water.After shaking, 10 μl of the resulting suspension is injected directly into the graphite furnace. The absorbance is measured at 349.9nm. The pyrocarbon treated graphite tube was most efective for the measurement of Ru. The calibration curve was liner below 2.5 μg/100cm3 (aqueous phase). The determination limits(3σ)were 0.08 μg/100cm3 (aqueous phase). The presence of such as Cu, Ni did not interfere. Interference by Fe could be masked by adding thiourea and 1, 10-phenanthroline and ammonium fluoride. The proposed method was applied to the determination of Ru in several water samples.View full abstractDownload PDF (898K) -
Shinichi TOTSUKA, Hisashi MATSUDA, Takayoshi SATO, Norio MINAGAWA1996 Volume 45 Issue 10 Pages 927-932
Published: 1996
Released on J-STAGE: May 25, 2010
JOURNAL FREE ACCESSA sensitive HPLC method with fluorescence precolumn-labeling using 4-hydroxymethyl-7-methoxycoumarin(HMC)was developed for the determination of fatty acid in milk or dairy products. Fatty acid was extracted by using hexane-diethyl ether(1 : 1). A reaction reagent was prepared by mixing 20mg of HMC, 50mg of 4-dimethylaminopyridine, 10ml of acetonitrile and 90ml of 1% dichloromethane solution of N, N'-dicyclohexylcarbodiimide. 1ml of the extract was added to 1ml of the reaction reagent and the mixture was allowed to stand for 70min at room temperature to form FFA-HMC derivatives. 10 μl of the reactant was injected into a reversed phase column and eluted with ethanol : acetonitrile=1 : 1. FFA-HMCs were separated completely within 44min by HPLC monitored by fluorescence(Ex. 330nm, Em. 395nm).Detection limits were 0.1 μg for each FFA in 1g of sample. The reproducibility of the HPLC measurements was 10.2% or less(RSD.). This method was applied successfully to the determination of FFA in a variety of dairy products.View full abstractDownload PDF (747K) -
Tatsushi WAKISAKA, Naoki MORITA, Masanobu WAKASA, Shinichi TERADA, Kaz ...1996 Volume 45 Issue 10 Pages 933-939
Published: 1996
Released on J-STAGE: May 07, 2010
JOURNAL FREE ACCESSAn energy dispersive X-ray fluorescence spectrometer (EDXRF) with monochromatic excitation has been developed for the direct determination of trace elements in organic matrices. Monochromatization of X-rays by a crystal monochromator is effective in improving the signal to background ratio.Detection limits are less than 0.1 μg g-1 by monochromatic excitation of Mo-Kα (17.4 keV) X-ray tube. But Ag, Cd and Sn can't be determined. The newly-constructed EDXRF with a combination of three monochromatic excitations (9.7, 17.4 and 40keV), can offer a higher sensitivity for the elements of atomic number larger than 22 (Ti). At optimum conditions, detection limits of 0.020.34 μg g-1 (mean value, 0.13 μg g-1) are ascertained for the 22 elements determined (TiHg and Bi), and satisfactory precision (within 1% R.S.D.) is obtained. The proposed method is applied to the direct determination of trace elements in the NIST fuel oil (SRM 1634b), and others. The results are in good agreement with the certified values.View full abstractDownload PDF (1076K) -
Hisomu NAGASHIMA, Kazuo KUBOYAMA1996 Volume 45 Issue 10 Pages 941-946
Published: 1996
Released on J-STAGE: May 29, 2009
JOURNAL FREE ACCESSA modified ion chromatographic (IC) microdetermination of phosphorus in organic compounds was developed. The recoveries of phosphorus (measured as PO43- ) by the conventional flask combustion method were rather low and dispersed, 4798% (4 compounds), when dilute aqueous hydrogen peroxide was used as an absorbing solution for collecting the combustion products, probably due to the production of phosphorus-containing anions other than phosphate.The IC method was applied to separate the polyphosphate components collected in the combustion solution, demonstrating the presence of orthophosphate (PO43- ), pyrophosphate(P2O74- ) and tripolyphosphate (P3O105- ). Boiling of the combustion sample solution in the presence of dilute sulfuric acid on a hot plate (200°C) for 20min was shown to convert all the phosphorus-containing anion species to orthophosphate. The simultaneous microdetermination of chlorine, bromine, sulfur and phosphorus in organic compounds was achieved by incorporating this post-combustion hydrolysis step into the conventional procedure.The analytical values thus obtained were in good agreement, within ± 0.3 %, with the theoretical values for four compounds tested.View full abstractDownload PDF (764K) -
Kunihiro WATANABE, Takayuki IKAI, Masayuki ITAGAKI1996 Volume 45 Issue 10 Pages 947-953
Published: 1996
Released on J-STAGE: May 29, 2009
JOURNAL FREE ACCESSThe fluorometric determination of La(III) with 2-hydroxy-5-methylbenzaldehyde semicarbazone(HMBS) and the substituent effects on the fluorescence intensities of La(III) complexes with salicylaldehyde semicarbazone derivatives have been investigated.La(III) easily reacts with salicylaldehyde semicarbazone derivatives at high pH range to form stable complexes.The fluorometric determination of La(III) was impossible without separation of La-complexes, because the excess reagent also fluoresced strongly in basic solution. Therefore, the extraction of La-complex into chloroform was studied in the presence of dodecylbenzensulfonate in order to separate the excess reagent.As a result, the determination of La(III) could be successfully carried out. Three kinds of salicylaldehyde semicarbazones, i.e., 2-hydroxy-5-methylbenzaldehyde semicarbazone (HMBS), 5-chloro-2-hydroxybenzaldehyde semicarbazone (CHBS) and 2, 4-dihydroxybenzaldehyde semicarbazone (DHBS), were examined as reagents for the determination of La(III). Among these, HMBS was found to be the most suitable ligand.The extractabilities of La-HMBS, La-CHBS, La-DHBS, were 96%, 98% and 34%, respectively. The detection limit with CHBS for La(III) was inferior to that with HMBS. La(III) could be detected above 25 ppb with HMBS, and the relative standard deviation for 400ppb of La(III) was 2.4% (n =7). The electron densities of three ligands were calculated by MOPAC. The magnitude of the electron density in the benzene ring of DHBS was smaller than those of the others, and the electron distribution was not homogeneous.A significant difference in electron density was not observed between DHBS and CHBS. The fluorescence quantum yield of dissociated ligand was larger than that of undissociated ligand. The magnitude of electron density in the benzene ring of the dissociated ligand was larger than that of the undissociated ligand.View full abstractDownload PDF (1039K) -
Atsushi UZAWA, Yoko IWAMOTO, Tadao OKUTANI1996 Volume 45 Issue 10 Pages 955-957
Published: 1996
Released on J-STAGE: May 29, 2009
JOURNAL FREE ACCESSNi and Co are adsorbed on activated carbon impregnated with 1, 2-cyclohexanediondioxime(AC-DOx). A simple and rapid determination method for trace amotnts of Ni and Co in bottom sediments by metal furnace AAS using direct heating of metals adsorbed onto AC was investigated. Ni(II) and Co(II) are adsorbed as AC-DOx after adjusting the pH to 8.0 for Ni(II) and 6.5 for Co(II). The proposed method was used to determine the amounts of several environmental reference standard materials, river and marine bottom sediments. The proposed method is simple and rapid, and has been applied to the determination of Ni and Co in river and marine bottom sediments.View full abstractDownload PDF (400K) -
Toshio OIMATSU, Taketoshi NAKAHARA1996 Volume 45 Issue 10 Pages 959-963
Published: 1996
Released on J-STAGE: January 15, 2010
JOURNAL FREE ACCESSAn analytical method for the determination of trace amounts of copper, calcium, magnesium and bismuth in titanium(IV) oxide was investigated using slurry introduction and direct atomization graphite furnace atomic absorption spectrometry(AAS). We prepared slurries of five commercial titanium(IV) oxide powders, and studied experimental parameters to get optimum atomization conditions for minimal matrix interference.We also analysed those elements by inductively coupled plasma atomic emission spectrometry(ICP-AES) and inductively coupled plasma mass spectrometry(ICP-MS). As a result, with the ICP-AES, each of the elements were affected by matrix spectral interference. With the ICP-MS, the determination of copper, calcium and magnesium suffered from overlapping peaks. For these reasons, neither ICP-AES nor ICP-MS methods produced satisfactory results. In contrast, the present AAS technique gave good results for the determination of the four elements. The lower limits (10σ) with the proposed method were 0.2 μg/g (copper), 1μg/g (calcium), 0.3 μg/g (magnesium) and 0.4 μg/g (bismuth) of sample.View full abstractDownload PDF (669K) -
Susumu KAWAKUBO, Kiyoshi OGIHARA, Masaaki IWATSUKI1996 Volume 45 Issue 10 Pages 965-970
Published: 1996
Released on J-STAGE: May 29, 2009
JOURNAL FREE ACCESSA sensitive and simple visual colorimetric method for the determination of vanadium has been developed using vanadium-catalyzed oxidation of ο-phenylenediamine (OPDA) with bromate in the presence of gallic acid as an activator.After 10min of reaction at pH 4.0 and 2030°C, the pH of the solution was readjusted to 7 with a tetraborate-NaOH buffer solution to stop the reaction. The solution (6ml) was placed in a cell with five optical path lengths of 20, 16, 12, 8 and 4 mm. The coloration of oxidized OPDA was compared with that of a color standard containing 1 (or 2) ng of vanadium for the determination of vanadium up to 5 ng. The same calibration graph with a linear range of 05 ng was obtained for V(IV) and V(V) by spectrophotometric measurements at 420 nm.The detection limits by the visual and spectrophotometric methods were 0.2 and 0.04 ng, respectively. For the visual method, the addition of F-effectively eliminated the interference from Fe(III). The visual method has significant merits for the simple determination of vanadium, especially in the field, and was successfully applied to river, lake, ground and tap water samples.View full abstractDownload PDF (1018K) -
Yutaka HAYASHIBE, Makiko WADA1996 Volume 45 Issue 10 Pages 971-974
Published: 1996
Released on J-STAGE: May 29, 2009
JOURNAL FREE ACCESSDownload PDF (793K)
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