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Volume 47, Issue 3
Displaying 1-8 of 8 articles from this issue
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Hirotsugu MINAMI, Yukari ISHIZU, Atsuko SHINOHARA, Momoko CHIBA, Ikuo ...1998 Volume 47 Issue 3 Pages 149-155
Published: March 05, 1998
Released on J-STAGE: February 16, 2010
JOURNAL FREE ACCESSIt has been found that spectral interferences based on the molecular absorbance occurs at 196.0 nm of the selenium absorption line when a selenium sample solution containing 100 μg/ml of palladium in 3 mol/l sulfuric acid as a matrix modifier is measured by graphite furnace AAS equipped with a polarized d.c. Zeeman-effect background-correction system. Spectral interferences were observed when both biological powdered samples or the above-mentioned solution samples were measured. The degree of the spectral interferences depended on the amounts of potassium coexisting in the samples. When the amounts of potassium coexisted at more than ca. 30 μg, the molecular absorbance at 196.0 nm increased tenfold compared with the certified values for the certified reference materials. It was considered that the spectral interferences were caused by the molecular absorption, such as potassium sulfide or potassium chloride, because it was not observed when a sample solution containing potassium nitrate was measured.View full abstractDownload PDF (1177K) -
Tatsushi WAKISAKA, Naoki MORITA, Tadashi HIRABAYASHI, Taketoshi NAKAHA ...1998 Volume 47 Issue 3 Pages 157-161
Published: March 05, 1998
Released on J-STAGE: February 16, 2010
JOURNAL FREE ACCESSA useful and rapid procedure is described for the determination of trace phosphorus, sulfur, chlorine, bromine, and iodine by means of an energy dispersive X-ray fluorescence spectrometer (EDXRF) with monochromatic excitations. Using monochromatic excitations, the detection limits for phosphorus, sulfur, chlorine (Cr-Kα, 5.41 keV), bromine (Mo-Kα, 17.44 keV), and iodine (W-continuum, 40 keV) were found to be 4.6, 1.7, 0.7, 0.09 and 0.5 μg g-1, respectively. The relative standard deviations in five replicate measurements were 0.91.3%. The proposed method was applied to the direct determination of sulfur in the NIST Residual Fuel Oil, and others. The results obtained by the proposed method were in good agreement with the certified values. Bromine in a seawater sample, as well as iodine and bromine in a brine sample were determined by the proposed method. The obtained results were in good agreement with those obtained by ion chromatography.View full abstractDownload PDF (796K) -
Norio MANABE, Kingo FURUKAWA, Tsuyoshi TOYODA, Sadao MORI1998 Volume 47 Issue 3 Pages 163-169
Published: March 05, 1998
Released on J-STAGE: June 30, 2009
JOURNAL FREE ACCESSThe best conditions for rapid baseline stabilization, a stable baseline, and precise measurements of the retention volumes and average molecular weight of polystyrene (PS) were studied. It was assumed that a stable baseline could be obtained by keeping the temperature difference between both sides of a refractive index (RI) detector cell, reference and sample, constant. Under this assumption, the best combination of the temperatures of the column, RI cell, room, and mobile phase were examined. The adjustment of the temperatures of the column, mobile phase and RI cell to room temperature, for example 25°C was the best for the stability of the baseline. This temperature condition made it possible to shorten the time to attain a stable baseline. The time required to stabilize the baseline was 40 minutes, and the baseline fluctuation was 2.2×10-7RIU/h. The second appropriate condition was keeping the temperatures of the column and RI at 40°C and those of the room and the mobile phase at 25°C. Adjusting the temperatures of the column and RI to room temperature was required if the temperature of the mobile phase was not controlled.View full abstractDownload PDF (1079K) -
Spectrophotometric determination of the average valence of cerium in Nd-Ce-Cu oxides with ο-tolidineKunihiro WATANABE, Naomori YOKOIWA, Masayuki ITAGAKI, Nobuyuki KOURA1998 Volume 47 Issue 3 Pages 171-177
Published: March 05, 1998
Released on J-STAGE: February 16, 2010
JOURNAL FREE ACCESSThe spectrophotometric determination of the average valence of Ce in Nd-Ce-Cu oxides was performed using ο-tolidine. Each sample was dissolved in a HCl solution in the presence of ο-tolidine, which was oxidized with Ce(IV) in a 2e step to intensely yellow quinonediimine in a weakly acidic solution. Then, Ce(IV) was reduced to Ce(III). Ce(IV) was determined over the range of 0.320μg based on the absorbance observed at 437 nm on the oxidant of ο-tolidine. The optimum conditions for the determination of Ce(IV) in Ce oxides were as follows: total volume, 6ml; ο-tolidine concentration, 1.7×10-3%; pH, 1.0 (adjusted with HCl); reaction time, 2min; reaction temperature, 65°C; sample amount taken, 0.21.1 mg. On the other hand, the total Ce was determined by inductively coupled plasma atomic-emission spectrometry. The average valence of Ce (nav) could be calculated according to the following equation: nav ={[Ce (IV)]/ [Ce]total}+3. The average valence of Pr in the Pr-Ba-Cu-O semiconductor was determined by the same procedure as that proposed for Ce. Cu(III) did not interfere with the determination of Ce(IV) and Pr(IV). The average valence of Ce in a sample was obtained to be 3.23. The results agree well with those obtained by the KMnO4 method. By the proposed method, the lower limit of Ce(IV) determination was 0.3 μg and the amount of consumed sample could be decreased down to 0.2 mg.View full abstractDownload PDF (997K) -
Kunihiro WATANABE, Kunihiro OHBA, Arkin IBURAIM, Masayuki ITAGAKI, Nob ...1998 Volume 47 Issue 3 Pages 179-185
Published: March 05, 1998
Released on J-STAGE: February 16, 2010
JOURNAL FREE ACCESSA new preconcentration on-line system for trace copper(II) determination was developed based on the adsorption of copper(II) on the walls of Teflon tubes using flow injection analysis(FIA). Copper(II) was concentrated as hydroxide or colloid on the inner walls of Teflon tubes. The present FIA apparatus had triple channels, and dual injectors were used in a carrier stream. A nitric acid solution (100μl) was loaded in the sample loop of one injector. The sample solution containing copper(II) was loaded in another injector, where copper(II) was adsorbed. The copper(II) adsorped on a Teflon capillary tube (3m in length, i.d. 0.5 mm) was eluted on-line with a nitric acid solution, and was then determined with ascorbic acid and ο-phenylenediamine by fluorometry. The copper(II) was determined over the range of 0.025 to 200 ppb by the present method. The detection limit for copper(II) was 0.008 ppb. The RSD was 2.3% for 1 ppb Cu(II) (n = 7). The treatment of Teflon tubes with a 2 M NaOH solution enhanced the adsorption of copper(II). The optimum conditions of copper(II) determination by the present method were as follows: sample solution, pH 6.0; NaOH concentration, 2 M; adsorption flow rate, 0.4 ml/min ; adsorption time, 10 min. The interference in the determination of copper(II) with diverse ions, i.e. V(V) Cr(VI), Fe (III), Hg(II), Mn(II), Cd(II), La(III), Y(III) and Tl(I) could be decreased by adsorption preconcentration without a masking agent. The results of a trace Cu(II) determination in tap water showed good agreement with the values obtained by graphite-furnace AAS.View full abstractDownload PDF (1005K) -
Kyoko FUJIMOTO, Masao ITO, Makoto SHIMURA, Keiichi YOSHIOKA1998 Volume 47 Issue 3 Pages 187-193
Published: March 05, 1998
Released on J-STAGE: February 16, 2010
JOURNAL FREE ACCESSThe determination of trace amounts of phosphorus in high-purity silicon has been investigated. A sample was decomposed by a mixed acid vapor of hydrofluoric acid and nitric acid in a pressure bomb. The presence of 0.5ml of sulfuric acid prevented the loss of phosphorus during the decomposition. Phosphorus in the residue was converted to molybdophosphate and collected on a polycarbonate filter as an ion pair with dodecyltrimethylammonium bromide (DTMAB). The molybdophosphate-DTMAB ion pair was dissolved in 0.2ml of conc. sulfuric acid, and diluted to 510ml with water. The molybdenum in the solution was determined by isotopic dilution/ICP-MS, which resulted in the determination of phosphorus. The interference with silicon, aluminium, and iron was almost negligible up to a concentration as high as 1001000 times that of phosphorus ; also, a μg g-1 level of arsenic in silicon materials did not interfere with the phosphorus determination. The lower limit of detection was under 0.01μg g-1 in silicon based on 3σ of blank values.View full abstractDownload PDF (2634K) -
Makoto TORIGAI, Tong OUYANG, Kiyoshi IWASHIMA, Masahiro OSAKO, Masaru ...1998 Volume 47 Issue 3 Pages 195-198
Published: March 05, 1998
Released on J-STAGE: June 30, 2009
JOURNAL FREE ACCESSMunicipal-waste incineration fly-ash samples were digested by microwave-digestion procedures with an acid mixture of HClO4-HNO3-HF. Then, selenium in the digested sample solution (in 1 M-HCl, trace-HClO4) was directly determined using graphite-furnace AAS with a Zeeman-effect background correction. Platform atomization was used and peak-area absorbance measurements were utilized. Palladium and nickel were used as modifiers. The palladium modifier stabilized selenium at a higher temperature than did the nickel modifier, resulting in a better sensitivity. An aqueous calibration curve was used and the method of additions was not necessary. The present investigated method was applied to the analysis of a certified reference material (BCR No. 176). The analytical result was in good agreement with the certified value. The present method has been successfully applied to the analysis of actual samples.View full abstractDownload PDF (439K) -
Hiroyuki SAKAI1998 Volume 47 Issue 3 Pages 199-200
Published: March 05, 1998
Released on J-STAGE: June 30, 2009
JOURNAL FREE ACCESSDownload PDF (360K)
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