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Volume 33, Issue 4
Displaying 1-20 of 20 articles from this issue
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Eijiro KAMATA, Ryozo NAKASHIMA, Shozo SHIBATA1984 Volume 33 Issue 4 Pages 173-178
Published: April 05, 1984
Released on J-STAGE: February 16, 2010
JOURNAL FREE ACCESSIn order to determine trace amounts of chromium in coal ash by atomic absorption spectrometry, two wet digestion procedures were examined. In procedure A, the sample was first treated with a mixture of hydrofluoric acid and nitric acid and then digested with an oxidation system, nitric acid-perchloric acid, in an open PTFE vessel at the temperature of below 150°C. Chromium in the digested solution was determined in a fuel-rich air-acetylene flame by an addition of 12000 ppm of sodium sulfate as an interference suppressor. The recovery of chromium in the coal fly ash sample of NBS SRM 1633a was 97 %. The relative standard deviations were 0.78 % for the sample of 1633a and less than 2 % for the other samples. In procedure B, the sample was digested in a sealed PTFE vessel with nitric acid-perchloric acid and then with hydrofluoric acid. The excess hydrofluoric acid was masked with boric acid. Chromium in the solution was determined in a nitrous oxide-acetylene flame without an interference suppressor. The recovery of chromium in the sample of 1633a was 100 %. The relative standard deviations were 4 % for the sample of 1633a and in the range of 5 to 8 % for the other samples. This higher value of relative standard deviation was caused by the fluctuation of the absorbance of chromium in a nitrous oxide-acetylene flame. An addition of interference suppressors to the solution obtained from the latter procedure was shown to be ineffective on the stabilization of absorbance. Although the recovery of chromium by the open vessel procedure could not reach to that by the sealed vessel procedure, chromium in the solution obtained from the open vessel procedure was determined with higher precision and sensitivity (1 % absorption = 0.08 ppm Cr).View full abstractDownload PDF (1225K) -
Norio FUKUZAKI, Yoshio ICHIKAWA1984 Volume 33 Issue 4 Pages 178-182
Published: April 05, 1984
Released on J-STAGE: February 16, 2010
JOURNAL FREE ACCESSThis paper describes a method for the collection and determination of particulate mercury in air. The particulate mercury can be collected sufficientry on a quartz fiber filter with a high-volume air sampler, and rapidly determined by flameless atomic absorption spectrophtometry with a combustion-gold trapping-heat vaporization procedure. The distribution of particulate mercury on the filter is uniform due to its relatively small particle size. Gaseous mercury gives no interference on the determination of particulate mercury. Vaporization of particulate mercury from dust during the collection process might be negligible, because loss of mercury could not be detected when particulate mercury-less air was passed through the dust, and because there was no difference between mercury contents in the dusts collected simultaneously with a pair of samplers by the different sampling methods (A : 9 h sampling-filter exchange-15 h sampling, B: 24 h sampling). Analytical results by this method agreed well with those by wet digestion method.View full abstractDownload PDF (1158K) -
I. Temperature characteristics of nitrogen sheath oxy-hydrogen flameKoichi NAKAJIMA, Takeo TAKADA1984 Volume 33 Issue 4 Pages 183-187
Published: April 05, 1984
Released on J-STAGE: June 30, 2009
JOURNAL FREE ACCESSA new nitrogen sheath oxy-hydrogen flame is described for use in the detection of sulfur-bearing compounds in molecular emission cavity analysis. Nitrogen was used as the sheathing gas, and oxygen (0.10.56 1 min-1) and hydrogen (46 1 min-1) were introduced at the center of the total consumption burner in usual way. As the flame itself is colorless and no emission of OH band could be detected in flame circumference, introducing air into the flame through its surrounding is shielded entirely. The oxygen introduced can be expected to be very well mixed and completely reacted with the excess hydrogen. Generally, the introduction of air or oxygen into hydrogen flame extinguishes the blue S2 emission, as a results of the destruction of S2 molecules to form sulfur-oxygen compounds. When the reaction between hydrogen and oxygen is immediately brought about on the top of the burner, however, the intensed S2 emission can be clearly seen in the cavity. The flame temperature at constant hydrogen flow rate exhibited a linear increase with increasing oxygen flow rate. The maximum temperature was obtained at place along the central vertical axis of the flame and was also found to vary linearly with the horizontal position in the high oxygen flame. The variation in the temperature with flame height is small at the flame center only (about 40°C, from 15 to 35 mm height). The flame temperature and composition can be controlled more exactly and regularly through adjustment of hydrogen and, oxygen flow rates in comparison with conventional nitrogendiluted hydrogen diffusion flame burning air. Linear calibration graphs for thiosulfate and sulfuric acid were obtained.View full abstractDownload PDF (858K) -
Masahiro NAKANO, Chukichi SEKIGUCHI, Hiroyuki WAKABAYASHI, Kenji SHIMA ...1984 Volume 33 Issue 4 Pages 188-191
Published: April 05, 1984
Released on J-STAGE: February 16, 2010
JOURNAL FREE ACCESSThe improved technique for the determination of germanium in medicinal plants was examined. Oxygen-flask combustion method was suitable to mineralize samples containing volatile germanium compounds in a closed system. After combustion, germanium was determined using the spectrophotometry with phenylfluorone. Using the proposed method, the high recovery percentages were obtained. Germanium in some commercially available medicinal plants was determined by the improved method. The method was also applied to the determination of germanium in Kaiware radish cultivated in medium containing germanium. The results indicated that germanium content increased 1630 hold of its original medium concentration.View full abstractDownload PDF (719K) -
Shogo SUZUKI, Shoji HIRAI1984 Volume 33 Issue 4 Pages 192-198
Published: April 05, 1984
Released on J-STAGE: February 16, 2010
JOURNAL FREE ACCESSA coaxial Ge (Li) detector (energy range of 1003000 keV) is conventionally used for the analyses of many radioactive nuclides which emitted above 100 keVγ-rays. However, the measurement of low energy γ-rays and X-rays (energy range of 10200 keV) have the possibility to improve analytical sensitivity of some elements. This study describes an application of Low Energy Photon Spectrometer (LEPS) with a planar pure Ge detector to the determination of elements in coal and coal fly ash by instrumental neutron activation analysis. NBS standard material coal (SRM 1632a and SRM 1635) and coal fly ash (SRM 1633a) samples (ca. 1080 mg) were irradiated for short time (5 min) at a thermal neutron flux of 1.5 × 1012 n cm-2 s-1 and for long time (5 h) at a thermal neutron flux of 3.2 × 1012 n cm-2 s-1 in Musashi Institute of Technology Research Reactor (MITRR). Low energy γ-ray and X-ray spectra for short time irradiation samples were measured for 1525 min after 430min of cooling and for 0.44h after 1830 h of cooling by a pure Ge detector (500 mm2 in area and 15 mm in depth) coupled with a 4096 channel multichannel analyzer. Gamma-ray and X-ray spectra ofr long time irradiation samples were measured for 110 h after 38d of cooling and for 1040 h after 1550 d of cooling. The spectra obtained were analyzed with a peak-fitting procedure by a minicomputer system (GAMA system), and the effect of self-absorption of γ-ray and X-ray was corrected. As the results, 29 elements in coal and fly ash could be determined. The concentration of trace elements were in good agreement with NBS certified values. The analytical sensitivities of Cu, I, Nd, Gd, Dy, Ho, Tm, and Lu by the planar pure Ge detector were higher than those by the coaxial Ge (Li) detector.View full abstractDownload PDF (1123K) -
Kiyoko TAKAMURA, Satoshi INOUE, Fumiyo KUSU1984 Volume 33 Issue 4 Pages 198-203
Published: April 05, 1984
Released on J-STAGE: June 30, 2009
JOURNAL FREE ACCESSAn anodically pretreated glassy carbon (GC) electrode was applied to the electrochemical determination of chlorpromazine (CPZ). The optimum condition for the pretreatment was attained by the anodic oxidation of GC electrodes in 0.5 mol dm-3 phosphate (pH 6.7) at +1.6 V vs. SCE for 2 min. By this treatment, the oxidation peak on the cyclic voltammogram of CPZ was enhanced by about 30 times. The peak current at +0.75 V is proportional to the concentration of CPZ and the linear relation was obtained ranging in concentration from 2 × 10-7 to 4 × 10-5 mol dm-3. The detection limit is 1 × 10-7 mol dm-3. The electrode was stable in the potential region of -0.5+1.2 V and gave reproducible data for the peak current of CPZ with R. S. D. value of about 3.5 % on repeated runs. The electrode can be kept in phosphate solution for a month with about 20 % decrease in the peak current of CPZ. Pretreatment of the electrode can be easily made. From these findings, application of such pretreated GC electrodes to trace analysis of CPZ in biological samples seems promising.View full abstractDownload PDF (1078K) -
Masahiro HORI, Mamoru HIRAKO, Katsuaki ISHII, Yoshitaka KOBAYASHI1984 Volume 33 Issue 4 Pages 203-209
Published: April 05, 1984
Released on J-STAGE: June 30, 2009
JOURNAL FREE ACCESSA simple and rapid method of pre-treatment was established for applying ion selective electrode of silver chloride membrane to the determination of chloride ion in environmental samples. The proposed methods enabled to avoid the interference from sulfide, cyanide, and iodide ion. The addition of potassium permanganate to the sample solution adjusted to pH 4 (TISAB) brought the more rapid and complete oxidation of sulfide than that of hydrogen peroxide and an aeration, and also was effective for iodide. The addition of excess potassium permanganate had not a bad effect upon the response and membrane. Though it eliminated to a certain extent the interference of cyanide it didn't bring the complete oxidation of cyanide. Therefore, nickel nitrate which formed nickel cyanide was added to the sample previously adjusted to the pH of about 11. The analytical procedures are as follows : Add successively a drop of 0.5 M potassium hydroxide and 0.2 ml of 1 M nickel nitrate to 20 ml of sample solution with stirring. After 3 min, add 2 ml of TISAB (5% potassium nitrate, pH 4) and 0.2 ml of 0.1 M potassium permanganate. Measure potential response after it has stabilized (after a lapse of time over 3 min). The maximum concentrations of interfering ions permitted for 10-4 M chloride ion are as follows : sulfide (10-3 M); cyanide (5 × 10-5 M); iodide (3 × 10-5M). Add merely TISAB and potassium permanganate to the sample containing cyanide smaller than one fiftieth of chloride.View full abstractDownload PDF (1412K) -
Shoji SAITO, Takeshi MIKI, Hiroshi ITO, Minoru KAMODA1984 Volume 33 Issue 4 Pages 209-212
Published: April 05, 1984
Released on J-STAGE: June 30, 2009
JOURNAL FREE ACCESSA gas-liquid chromatographic condition was studied to determine simultaneously volatile and non-volatile organic acids as butyl ester. After surveying the liquid phase of column for the separation of fourteen organic acid butyl esters, propionate, butyrate, iso-valerate, valerate, glycolate, lactate, levulinate, oxalate, malonate, succinate, fumarate, malate, aconitate, and citrate. A 2.0 m × 3.0 mm glass column of 2.0 % Silicone OV-17 plus 1.0 % Reoplex 400 on Gas Chrom Q was selected as an analytical column. Twelve organic acid butyl esters except fumarate and succinate could be separated with reported conditions.View full abstractDownload PDF (623K) -
Toshio YAO, Kuniyuki NAKANISHI, Tamotsu WASA1984 Volume 33 Issue 4 Pages 213-217
Published: April 05, 1984
Released on J-STAGE: February 16, 2010
JOURNAL FREE ACCESSA flow injection method for the specific assay of glucose was examined by the use of chemically modified enzyme membrane electrodes (CMEMEs) as the amperometric detector. The CMEME was constructed by cross-linking glucose oxidase and catalase(GOD-CT electrode), or glucose oxidase and peroxidase (GOD-POD electrode) with bovine serum. albumin using glutaraldehyde on a platinum electrode silanized with 3-aminopropyltriethoxysilane. The GOD-CT and GOD-POD electrodes are based on the amperometric detection of dissolved oxygen consumed and ferricyanide generated by the following enzyme reactions, respectively:
β-D-glucose+1/2 O2
GOD-CT→δ-D-gluconolactone+ H2O
(Eapp=-0.7 V vs. Ag/Ag+)
β-D-glucose+O2+2[Fe(CN)6]4-+2H+
GOD-POD→δ-D-gluconolactone+2[Fe(CN)6]3-+2H2O
(Eapp=0.0 V vs. Ag/Ag+)
The peak currents are linearly related to the glucose concentration in the ranges 20800 mg dl-1 for 5 μl injections at the GOD-CT electrode and 30400 mg dl-1for 1 μl injections at the GOD-POD electrodes. The peak width was ca. 6 s at a flow rate of 1.9 ml min-1, and so glucose in human serum and urine could be determined at a rapid determining rate with satisfactory precision (24 % R. S. D.). The CMEMEs retained most of their original activities after repetitive use for two months.View full abstractDownload PDF (753K) -
Shigeki DAISHIMA, Yoshio IIDA1984 Volume 33 Issue 4 Pages 218-221
Published: April 05, 1984
Released on J-STAGE: June 30, 2009
JOURNAL FREE ACCESSThe ion source temperature, ionization chamber pressure and the kind of reagent gas were examined to find the optimum experimental conditions for organic trace analysis by chemical ionization mass spectrometry with a Finnigan 3300E gas chromatograph mass spectrometer. Toluene, dodecane, methyl caplate, and diethyl phthalate were used as the model compounds. The lower ion source temperature, e.g. 70 °C, and the ionization chamber pressure of about 1 Torr were suitable to high sensitive and/or selective detections. The quasi-molecular ions, (M±H)+, were generated more effectively under the above conditions. The influence of reagent gas was studied with methane, water, methyl alcohol, isobutane or ammonia as a reagent gas and phthalic acid esters, butylbenzenes, 2-ethoxyethyl acetate(2-EEA), and 3-methoxybutyl acetate (3-MBA) as samples. The intensities for MH+ ion of 2-EEA and 3-MBA in isobutane reagent gas, respectively, were 8 and 28 times stronger than those in methane reagent gas.View full abstractDownload PDF (875K) -
Takashi YAMASHIGE, Manabu YAMAMOTO, Yasumasa SHIGETOMI, Yuroku YAMAMOT ...1984 Volume 33 Issue 4 Pages 221-223
Published: April 05, 1984
Released on J-STAGE: June 30, 2009
JOURNAL FREE ACCESSVarious wet digestion procedures were examined for the determination of iron, manganese, zinc, copper, lead, cadmium, and nickel in coal fly ash. The recommended procedure was as follows : a 0.3 g of sample was heated gently in a mixture of 15 ml of hydrofluoric acid, 20 ml of hydrochloric acid and 3 ml of hydrogen peroxide for about 2 h and the solution was evaporated to dryness. The residue was dissolved in 20 ml of 5 M hydrochloric acid by heating gently. After filtering the insoluble residue, the filtrate was adjusted to 50 ml with 0.5 M hydrochloric acid. The concentrations were determined directly, or after extraction with diethyldithiocarbamate in butyl acetate for the metals of lower concentrations, by atomic absorption spectrometry in an air-acetylene flame. In the latter case, a large amount of iron was eliminated by the extraction from 10 M hydrochloric acid with the isopentyl acetate. The present procedure was applied. for the analyses of coal fly ash samples of NBS SRM-1633a and the results were in good agreement with certified or tentative values. In the case of the acid digestion procedure without hydrofluoric acid, about 38 to 59 % lower values were observed for these elements, indicating that the decomposition of silicate matrix was necessary for the determination of total amount of metals in coal fly ash.View full abstractDownload PDF (723K) -
Masakazu DEGUCHI, Kazuhito WADA, Kiyotoshi MORISHIGE, Itsuo OKUMURA, K ...1984 Volume 33 Issue 4 Pages 223-226
Published: April 05, 1984
Released on J-STAGE: June 30, 2009
JOURNAL FREE ACCESSThe procedure was as follows : 0.10.2g of a sample containing less than 20 μg of gallium was dissolved by heating in 5 ml of hydrochloric acid (2+1). To the solution obtained, were added 0.1 ml of 20 % titanium trichloride solution and 5 ml of hydrochloric acid(2+1). The gallium in the solution was extracted twice with 5 ml each of isopropylether by shaking for 1 min. The organic phase was washed 5 times with 2 ml each of hydrochloric acid(2+1) by shaking for 15 s. The organic phase was evaporated to dryness on a water bath, and the residue was dissolved in 2 ml of hydrochloric acid (1+100) and diluted to 10 ml with water. To an aliquot containing 0.0053.0μg of gallium, were added 0.1 % sodium fluoride solution (Ga<0.1μg : 0.05 ml, Ga> 0.1μg : 0.1 ml), 2 ml of 0.05 % HSS solution in DMF and 0.5 ml of 2 w/v % ammonium acetate solution. The pH of the solution was adjusted to 3.8±0.1 with hydrochloric acid or ammonia water, and the solution was diluted to 25 ml with water. The solution was heated at 50°C for 10 min in a water bath. After cooling to room temperature, the fluorescence intensity was measured at 500 nm (λ excitation : 410 nm) against the standard uranine solution (0.05 μg/m1 or 0.2 μg/ml). The proposed method could be applied to the determination of gallium above 0.05 ppm in practical samples with satisfactory results.View full abstractDownload PDF (831K) -
Akira HOSHINO, Shuichi ISO, Mitsuo ITO1984 Volume 33 Issue 4 Pages 226-228
Published: April 05, 1984
Released on J-STAGE: June 30, 2009
JOURNAL FREE ACCESSThe chemical form of hydrogen in lithium oxide is mainly lithium hydroxide, which is formed from the oxide and atmospheric moisture during its storage. The reaction of the hydroxide with carbon monoxide afford hydrogen gas and carbonate, so that hydrogen content in lithium oxide can be easily determined by the following method : lithium oxide sample (100 to 500 mg) is placed on a reaction tube (test-tube type, 15 mm i.d. × 200 mm, glassware). Then, carbon monoxide gas is passed through the tube at 80 ml/min and the tube is heated at 390 °C for 15 min. The hydrogen evolved from the sample is determined by using thermal conductivity detector. The evolution profile of hydrogen gas with the reaction of lithium hydroxide and carbon monoxide was influenced by physical property (density of powder) of sample rather than its hydrogen content. Carbonate in sample did not interfere with the determination of hydrogen. The lower limit of determination was 0.002 % for 500 mg of sample. The required time for analysis was about 20 min after the sample was weighed under a dried atmosphere in gloved box. The standard deviations for the determination of 0.028 %, 0.18%, and 0.70 % of hydrogen were 0.004 %, 0.01 %, and 0.05 %, respectively.View full abstractDownload PDF (523K) -
Yûetsu DANZAKI, Minoru HOSOYA1984 Volume 33 Issue 4 Pages T31-T34
Published: April 05, 1984
Released on J-STAGE: February 16, 2010
JOURNAL FREE ACCESSThe EDTA titrimetric or spectrophotometric determination of tin (>1 %) in niobium-base alloys usually requres a separation of tin from the matrix. The separation procedure was investigated. The EDTA titrimetry after distillation of tin tetrabromide offered good results. The spectrophotometry was not suitable for the determination of tin contained more than 1 % in the alloys. Procedure : a sample (<20 mg as tin) was dissolved with 10 ml of HNO3 (1+1) and 5 ml of HF. Evaporate the solution to the evolution of SO3, fume after adding 60 ml of H2SO4(1+1), and transfere the solution to the distilling flask with water. After adding 15 ml of HBr, distillation was continued in a stream of CO2, on a mantle heater to the evolution of fume of SO3, and the distillate, SnBr4 was absorbed in 50 ml of H2SO4(3+17). After standing for 10 min at the room temperature, 15 ml of HBr was added to the distilling flask, and distille the solution in which tin remains as SnBr4. Evaporation was carried out untill the distillate was concentrated to 23ml, after decomposition of HBr with HC1 (20 ml) and HNO3 (20 ml) on the warm bath. The salts in the distillate were dissolved with several ml of water on heating. After cooling the solution, 25 ml of a 0.01 M EDTA solution were added to it, and adjusting the pH of the solution to 5.05.5 with hexamethylenetetramine, the excess EDTA was titrated with a 0.01 M Pb(NO3)2 standard solution by using xylenol orange as an indicator.View full abstractDownload PDF (692K) -
Michiko NAMIKI, Kichinosuke HIROKAWA1984 Volume 33 Issue 4 Pages T34-T38
Published: April 05, 1984
Released on J-STAGE: June 30, 2009
JOURNAL FREE ACCESSNiobium, titanium, and zirconium which are constituents of superconducters or of some refractory materials were determined by inductively coupled plasma (ICP) emission spectrometry. A niobium base alloy containing titanium, tantalum, copper, gallium, and others was dissolved in sulfuric acid, nitric acid, and hydrofluoric acid in a platinum evaporating dish by heating. After fuming of sulfuric acid, the salt formed was dissolved in dilute hydrogen peroxide (2%). The solution was further diluted with diluted sulfuric acid and sprayed into the ICP. The emission intensity at NbII 309.42 nm and Ti II 334.90 nm, Ti II 323.45 nm or Ti II 370.62 nm were measured, respectively, and overlapping effects of the spectra of these elements were corrected for the determination of them. In order to determine zirconium in sintered zirconiumsilicon carbides, a sample was fused with sodium carbonate in a platinum crucible. The salt was dissolved in water, and hydrofluoric acid was added together with sulfuric acid.After the finishing of the evaporation procedure of silicium fluoride by addition of hydrofluoric acid drop by drop during the fuming of sulfuric acid, the salt was dissolved in water and diluted. The resultant solution was used to determine zirconium by using Zr II 339.20 nm. These procedures were applied for the determination of several per cent of niobium, titanium, and zirconium in superconducters and some refractory materials.View full abstractDownload PDF (942K) -
Tetsuya KIRIYAMA1984 Volume 33 Issue 4 Pages T38-T41
Published: April 05, 1984
Released on J-STAGE: June 30, 2009
JOURNAL FREE ACCESSVanadium, cobalt, and titanium in environmental standard reference materials were determined spectrophotometrically after anion-exchange separation. For vanadium and cobalt a sample was dry-ashed at 420 °C, and then decomposed with a mixture of perchloric, nitric, and hydrofluoric acids. Both metals were adsorbed by anion-exchange on an Amberlite CG 400 (SCN- type) column from 0.1 M ammonium thiocyanate-0.1 M hydrochloric acid solution. The vanadium and cobalt were consecutively stripped out of the column by elution with 12 M hydrochloric acid and then 2 M perchloric acid. Vanadium was subsequently purified by anion-exchange from 0.1 M hydrochloric acid-3 % hydrogen peroxide and cobalt from 6 M hydrochloric acid. They were determined spectrophotometrically with 4-(2-pyridylazo) resorcinol.For titanium the dry-ashed sample was decomposed with a mixture of perchloric, nitric, and hydrofluoric acids; titanium was adsorbed by anion-exchange on an Amberlite CG 400 (SCN- type) column from 1 M ammonium thiocyanate-1 M hydrochloric acid solution and eluted selectively with 4 M hydrochloric acid. Titanium was determined spectrophotometrically with diantipyryl methane. Vanadium, cobalt, and titanium in four NIES environmental standard reference materials were determined according to the procedures mentioned. Vanadium in the NIES's pond sediment, pepperbush, chlorella, and mussel were 220 ppm, 0.61 ppm, 0.51 ppm, and 0.51 ppm, respectively; the respective values for cobalt were 30 ppm, 17 ppm, 1.0 ppm, and 0.39 ppm; and those for titanium were 0.49 %, 11 ppm, 3.1 ppm, and 6.4 ppm.View full abstractDownload PDF (575K) -
Koji TAKEUCHI, Takashi IBUSUKI1984 Volume 33 Issue 4 Pages E107-E113
Published: April 05, 1984
Released on J-STAGE: June 30, 2009
JOURNAL FREE ACCESSSulfur dioxide in aqueous solution (HSO3-) was determined by chemiluminescence method based on a reaction between SO2 and KMnO4 in the liquid phase. Sulfur dioxide in slightly alkaline solutions containing formate ion (2 μM) was stable against oxidation by dissolved oxygen for the period of measurement. Chemiluminescence yield was proportional to HS03- concentration in the range of 0.8-100 ng SO2 ml-1, and the reproducibility was assured to be 2-6% in relative standard deviation. While some oxidizing agents, halide ions, transition metal ions and nitrite ion decreased the light yield to some extent, no interference was observed with regard to most of coexistent ions. The proposed method is applicable to determination of ppb level SO2 in rain water.View full abstractDownload PDF (831K) -
Yuzo TAMARI1984 Volume 33 Issue 4 Pages E115-E122
Published: April 05, 1984
Released on J-STAGE: June 30, 2009
JOURNAL FREE ACCESSA fluorimetric analysis for the determination of nano gram amounts of selenium in rocks has been developed. The analysis has been made up by the procedures of decomposition of rocks, extraction, back-extraction of selenium, and its fluorimetric determination with 2, 3-diaminonaphthalene (DAN). The reagent purification steps to minimize its blank value to low as possible have been discussed. Furthermore, the addition of EDTA-NaF to mask coexisting iron in the extraction has been discussed. This fluorimetric method has been applied to the rock reference materials issued by the Geological Survey of Japan.View full abstractDownload PDF (797K) -
Masahito SUGIYAMA, Osamu FUJINO, Masakazu MATSUI1984 Volume 33 Issue 4 Pages E123-E129
Published: April 05, 1984
Released on J-STAGE: June 30, 2009
JOURNAL FREE ACCESSThe determination of barium at a trace level by graphite furnace atomic absorption spectrometry was described. The reproducibility was improved to 3.6 % by the use of pyrolytic graphite coated furnaces. Moreover, the preconcentration and separation of barium from sea water by solvent extraction were investigated and applied to the determination of barium in sea water by the graphite furnace atomic absorption spectrometry. Barium was quantitatively separated and concentrated from interfering elements in sea water by the use of a mixture of 1-phenyl-3-methyl-4-benzoylpyrazol-5-one and tri-n-octylphosphine oxide as extractants, and the mean value of the recovery was 98.6 %. Barium in the Pacific Ocean surface water was determined and 5.6 μg dm -3 was found.View full abstractDownload PDF (636K) -
Jun-ichi ANZAI, Toshie KUSANO, Tetsuo OSA, Hideki NAKAJIMA, Tadayuki M ...1984 Volume 33 Issue 4 Pages E131-E136
Published: April 05, 1984
Released on J-STAGE: June 30, 2009
JOURNAL FREE ACCESSThe gate of ion sensitive field effect transistor (ISFET) was coated with urease-albumin membrane to fabricate a micro urea sensor. Potentiometric response of the sensor is markedly dependent on the nature of the membranes. Using the sensor with a thiner membrane (ca. 2μm), linear response with a slope of -44 mV/decade has been obtained over the range of 1×10-4-5×10-3mole/dm3 (M) urea concentration, response time being 2 min. In contrast, for the thicker membrane (ca. 10 μm), Nernstian response with 30 min of the response time has been obtained. The diffusion rate of H+ or OH- in the membranes has been estimated to be a main factor governing the response time of the sensor. Some operating variables such as the buffer concentration and the life time of the sensor have been also examined.View full abstractDownload PDF (663K)
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