Vol. 51 No. 10
October, 2002
Gaku Ishiguro and Hisanori Imura**
**Department of Environmental Sciences, Faculty of Science, Ibaraki University, Bunkyo, Mito-shi, Ibaraki 310-8512
(Received 2 July 2002, Accepted 9 September 2002)The enantiomer separation of 5-dimethylamino-1-naphthalene sulfonyl (Dns) derivatives of D,L-phenylalanine and D,L-isoleucine has been studied by capillary zone electrophoresis (CZE) mediated with β-cyclodextrin (β-CD) as a chiral selector. The baseline separation of the respective d and l isomers was observed at the pH region around each isoelectric point, i.e., pH 2.5-4.5, except for the isoelectric point, itself. To understand such phenomena, the solution equilibria of the acid dissociation of Dns-D,L-Phe (designated by HA for the neutral species) and the formation of inclusion complexes with β-CD were studied by CZE at 25°C and an ionic strength of 0.005 M. The electrophoretic mobility (µe) of Dns-D,L-Phe was measured as a function of the pH and of the β-CD concentration, and analyzed by a three-dimensional non-linear least-squares method (SigmaPlot). The acid-dissociation constants of H2A+ and HA±, the formation constant of the inclusion complexes, HA±·CD and A-·CD, and the electric mobilities of H2A+, A-, and A-·CD were determined and analyzed. The high enantiomer-separation ability observed around the isoelectric point was ascribed to a large difference in the formation between D-HA±·CD and L-HA±·CD.
Keywords : capillary electrophoresis; enantiomer separation; equilibrium constants; dansyl-D,L-amino acid; β-cyclodextrin.
Noboru Hiraki**, Akinori Isozaki*** and Hisomu Nagashima****
** Tokyo Kaseigakuin high school, 22, Sanbanchou, Chiyoda-ku, Tokyo 102-8341
*** Department of Materials and Applied Chemistry, College of Science and Technology, Nihon University, 1-8-14, Kanda -Surugadai, Chiyoda- ku, Tokyo 101-8308
**** NAC Techno Service Co., Ltd., 5-21-39, Kamisaginomiya, Nakano-ku, Tokyo 165-0031
(Received 1 May 2002, Accepted 20 August 2002)A method for the determination of nitrite and nitrate ions has been developed for ion-pair chromatography(RP-HPLC) with a new C30 column, coupled with an UV detector at 210. A phosphate buffer (pH 6.0) containing 2 mM tetrabutylammonium (TBA-OH) in 10(v/v)% acetonitrile was used as an optimal mobile phase for the separation of six anions (NO2-, Br-, NO3- SeO32-, SeO42- and I-). The six anions were efficiently separated within 25. Especially, the calibration curves of the nitrite and nitrate ions, to 50.0 µg/ml from 0.05 µg/ml, were linear with excellent correlation coefficients of more than 0.999 and a relative standard deviation of under 1% from 10 repeated measurements; and limits of detection were 5 ng/ml(S/N=3).
Keywords : ion-pair chromatography; inorganic anions; UV detector; tetrabutylammonium; new C30-silica column.
Masako Ezoe, Miho Sasaki, Akiko Hokura, Izumi Nakai**, Yasuko Terada***, Tatsuki Yoshinaga, Katsumi Tukamoto**** and Atsushi Hagiwara*****
** Faculty of Science, Tokyo University of Science, 1-3, Kagurazaka, Shinjuku-ku, Tokyo 162-8601
*** Japan Synchrotron Radiation Research Institute, 1-1-1, Kouto, Mikazuki-cho, Sayo-gun, Hyogo 679-5198
**** Ocean Research Institute, the University of Tokyo, 1-15-1, Minamidai, Nakano-ku, Tokyo 164-8639
***** Graduate School of Science & Technology, Nagasaki University, 1-14, Bunkyou-machi, Nagasaki 852-8521
(Received 5 June 2002, Accepted 10 September 2002)Two-dimensional imaging and a quantitative analysis of trace elements in rotifer, Brachionus plicatilis, belonging to zooplankton, were carried out by a synchrotron radiation X-ray fluorescence analysis (SR-XRF). The XRF imaging revealed that female rotifers accumulated Fe and Zn in the digestive organ and Fe, Zn, Cu, and Ca in the sexual organs, while the Mn level was high in the head. From a quantitative analysis by inductively coupled plasma mass spectrometry (ICP-MS), we found that rotifers eat the chlorella and accumulate the above elements in the body. The result of quantitative analyses of Mn, Cu, and Zn by SR-XRF in a single sample is in fair agreement with the average values determined by ICP-MS analyses, which were obtained by measuring a large number of rotifers, digested by nitric acid. The present study has demonstrated that SR-XRF is an effective tool for the trace element analysis of a single individual of rotifer.
Keywords : synchrotron radiation X-ray fluorescence analysis; micro beam; plankton; two-dimensional XRF imaging; elemental distribution.
Hiroaki Fukui and Osamu Fujino**
**Research Institute for Science and Technology, Kinki University, Kowakae, Higashi-Osaka-shi, Osaka 577-8502
(Received 30 April 2002, Accepted 15 August 2002)A method for determining of manganese, iron, zinc and copper in shell sample was examined using solvent extraction/ICP-AES (inductively coupled plasma-atomic emission spectrometry). Spectral interference and negative interference by calcium for these 4 elements were observed. Therefore, manganese, iron, zinc and copper were separated from macro-calcium using solvent extraction. Sodium diethyldithiocarbamate was used as a chelating reagent, and hexyl acetate was selected as an organic solvent. Manganese, iron, zinc and copper were quantitatively extracted at pH 6, and separated from calcium using this extraction system. The proposed method was applied to the determination of these elements in hard tissues in several shellfish specimens (limnetic and thalassic). In these element contents, the manganese concentration in a limnetic shellfish (Ikecho-gai) was found to be as high as 103 ppm.
Keywords : ICP-AES; shellfish; solvent extraction; sodium diethyldithiocarbamate; hexyl acetate.
Akimitsu Ishihara and Hiroshi Nakamura**
**Department of Analytical Chemistry, Faculty of Pharmaceutical Sciences, Science University of Tokyo, Ichigaya-funagawara-machi, Shinjuku, Tokyo 162-0826
(Received 7 May 2002, Accepted 8 August 2002)The purpose of this study is to apply near infrared spectroscopy (NIRS) to the field of forensic science. In the present paper, the non-destructive method was applied to the qualitative and quantitative analyses of the principal ingredient in tablets. By analyzing the second derivative spectra of powdered tablets, characteristic absorption bands relevant to functional groups were found, which being successfully utilized for the determination of the principal ingredients.
Keywords : near infrared spectroscopy; second derivative spectra; acetaminophen; phenacetin; phenol; acetanilide; qualitative analysis; quantitative analysis.
Satoru Mizuki, Kazuhiro Honda**, Yoshihito Mori***, Akira Sato**** and Seiichiro Nakabayashi*****
** Department of Applied Chemistry, Faculty of Engineering, Kanagawa Institute of Technology, 1030, Shimoogino, Atsugi-shi, Kanagawa 243-0292
*** Department of Chemistry, Faculty of Science, Ocyanomizu University, 2-1-1, Ohtsuka, Bunkyo-ku, Tokyo 112-8610
**** Department of Electronic Engineering, Faculty of Engineering, Shonan Institute of Technology, 1-1-25, Tsujidoh-nishikaigan, Fujisawa-shi, Kanagawa 251-0046
***** Department of Chemistry, Faculty of Science, Saitama University, 255, Shimoohkubo, Saitama 338-8570
(Received 1 May 2002, Accepted 10 September 2002)It was made quantitatively clear that the oxidative polymerization process of aniline by S2O82-ion in a highly concentrated hydrochloric acid aqueous solution was a clock reaction. It was strongly dependent on the concentration of S2O82-ion at the start time of the clock reaction. The rate-determining process of the reaction was a one-electron transfer process from C6H5NH2 to S2O82- ion. A possibility was strongly indicated that the strong magnetic field impression effect for this electron-transfer process acted as an inhibitive effect. Moreover, it became clear that the strong magnetic field impression did not influence the formation process of polyanilin. Also, it was indicated that the formation of polyaniline was suppresed by the reaction of the aniline radical with the dissolved oxygen.
Keywords : aniline hydrochloride; peroxydisulfuric asid; clock reaction; oxidation polymerization; strong magnetic field.
Hiroyuki Wada, Hiroyuki Ueyama, Michinori Waki, Shigeori Takenaka and Makoto Takagi**
**Department of Applied Chemistry, Graduate School of Engineering, Kyushu University, 6-10-1, Hakozaki, Higashi-ku, Fukuoka-shi, Fukuka 812-8581
(Received 29 April 2002, Accepted 19 August 2002)Protein or peptide chips are expected to be valuable tools for detecting and analyzing interactions involving proteins and peptides in post-genome projects. As a preliminary study aimed at such a chip technology, a differential pulse voltammetry was successfully used to detect the electrostatic interaction between the charged chemical species on an electrode and those in the solution. Specifically, a gold electrode surface was modified through thiol chemistry by anionically-/cationically- and multi-charged peptides (peptide electrodes). The electrodes were used to detect anionically or catinonically charged ferrocene-containing species (ligands; including a peptidic derivative) in solution. Unique DPV signals due to a ferrocene redox reaction were obtained when the nature of charge on the peptide electrode matched that of the ligand in solution. The magnitude of the signal correlated with the charge of the peptide molecule on the electrode, indicating that the binding affinity of the ligands was based on an electrostatic interaction with the peptides on the electrode surface. The results as a whole indicate that ferrocene labeling can be a useful means to electrochemically detect some specific interactions taking place between peptides on an electrode surface and those in solution.
Keywords : peptide-immobilized gold electrode; electrochemical detection; ferrocene labeling; electrostatic interaction; protein chip.
Tomoko Serizawa, Shanhu Bao and Toshiaki Nomura*
*Department of Chemistry, Faculty of Science, Shinshu University, 3-1-1, Asahi, Matsumoto-shi, Nagano 390-8621
(Received 18 April 2002, Accepted 1 July 2002)Sodium oleate, which is the main component of commercial solid soaps, was adsorbed on a quartz plate coated with and without collagen by means of electrode-separated piezoelectric quartz crystal measurements. Sodium dodecylbenzenesulfonate (DBS), which is the main component of commercial liquid detergents, was also adsorbed on collagen, but was not on the quartz plate. The frequency shifts caused by the adsorption of sodium oleate or DBS remained even if water was flowed. It was supposed that the soap components adhered onto glasses, dishes and human skin would remain as if they were rinsed with water and hot water. The sodium oleate and DBS were adsorbed in a weak acid solution and at high temperature, and desorbed in 0.01% of sodium carbonate or 0.05% of a sodium hydrogencarbonate solution.
Keywords : piezoelectric quartz crystal; sodium oleate; dodecylbenzenesulfonate; detergent; collagen.
Yuta Miyamae, Tsuyoshi Matsumoto, Kenichi Yoshizawa and Junko Tsuchiya
*Central Laboratory, POLA Chemical Industries, Inc., 560, Kashio-cho, Totsuka-ku, Yokohama 244-0812
(Received 27 May 2002, Accepted 8 July 2002)Cosmetics are mixtures of some surfactants, oils and other ingredients. A novel analytical method that requires no prolonged pretreatment to determine various different surfactants individually in mixtures is needed. We previously reported a new and simplified analytical method for mixtures of anion and amphoteric surfactants using liquid chromatography/mass spectrometry (LC/MS). In this study, we developed a method that made it possible to determine cationic and nonionic surfactants individually in mixtures. To analyze nonionic surfactants, it was necessary to prepare the best condition for each group with similar molecular structures. We confirmed that this method was applicable for the determination of cationic and nonionic surfactants individually in several cosmetic lotions and creams.
Keywords : LC/MS; cationic; nonionic; anionic; amphoteric; surfactants; determination.
Kunihiro Watanabe, Kiwamu Noda and Masayuki Itagaki*
*Department of Pure and Applied Chemistry, Faculty of Science and Technology, Tokyo University of Science, 2641, Yamazaki, Noda-shi, Chiba 278-8510
(Received 5 March 2002, Accepted 30 July 2002)It is well-known that the colors of azo compounds decrease with hydrogen peroxide, and that the reactions are accelerated in the presence of iron or manganese. Therefore, the phenomena can be used to determine iron and manganese by catalytic analysis . The discoloration of azo compounds with hydrogen peroxide has been explained by radicals produced as a result of the Fenton reaction. However, the hydroxyl radical and superoxide anion radical were presumed by only a UV-visible method in the presence of azo compounds. In this study, the radicals derived from hydrogen peroxide were confirmed by ESR in the presence of azo compounds. Hydroxyl radicals were detected by the ESR spintrapping method with 5,5-dimethyl-1-pyrroline-1-oxide (DMPO). The amount of radicals obtained in the aqueous phase was estimated by the peak height in the ESR spectra. The typical DMPO-OH spectrum was obtained in the presence of an azo compound. The conditions were as follows: Fe, 0.33 ppb; H2O2, 0.4%; pH, 10.1; DMPO, 0.04 g; total volume, 1.5 ml; magnetic field, 337±7.5 mT. Superoxide anion radicals were detected by using a reduction reaction of Nitro blue tetrazolium (NBT). Further, the anion radicals were confirmed by the suppression effect of superoxide dismutase (SOD) on the reduction reaction of NBT. The tridentate ligand azo compound has accelerated the Fenton reaction to work as an activator in the catalytic determination of manganese and iron. It was concluded that the radicals derived from hydrogen oxide attacked the azo compound to decrease the color of the azo dye as an indicator reagent.
Keywords : superoxide anion radical; hydroxyl radical; catalytic analysis; Fenton reaction; ESR; Arsenazo III.
Hidekazu Miyahara, Hironobu Yabuta, Yasushi Hayashi, Eiki Hotta and Akitoshi Okino*
*Department of Energy Sciences, Tokyo Institute of Technology, 4259, Nagatsuta, Midori-ku, Yokohama 226-8502
(Received 10 May 2002, Accepted 31 July 2002)In order to improve the plasma properties of helium inductively coupled plasma (ICP), He ICP with a hydrogen additive was studied. Measurements of spectroscopic characteristics were carried out to confirm the effects of adding hydrogen gas. It was found that the atomic emission intensity of analytical lines increases up to hydrogen flow rate of 0.05 to 0.09 l min-1, and then decreased. The emission intensities of Cs, Cl, and Mg were enhanced by factors of 2, 1.5 and 4, respectively. Compared to our usual He-ICP, the excitation and the rotational temperature increased from 3500 to 4800 K and from 2400 to 2900 K, while the electron number density decreased by 30%.
Keywords : helium ICP; hydrogen; excitation temperature; electron number density; robustness.
Masahiko Tsuchiya*, Yasuo Shida**, Kenichi Kobayashi, Mitsumasa Tajima and Shoichi Okouchi***
*All correspondences should be addressed to Masahiko Tsuchiya; 4-37-27, Kugayama, Suginami-ku, Tokyo 160-0082
**Tokyo University of Pharmacy and Life Science, 1432-1, Horinouchi, Hachiohji-shi, Tokyo 192-0392
***Department of Material Chemistry, Hosei University, 3-7-2, Kajinomachi, Koganei-shi, Tokyo 184-8584
(Received 6 June 2002, Accepted 1 August 2002)Studies of clusters are important for understanding the chemical reactions in solutions. Liquid ionization (LPI) mass spectrometry (MS) gives information about hydrogen-bonded clusters at liquid surface. By improving techniques for introducing liquid smples, the LPI mass spectra of a 40%(v/v) ethanol aqueous solution showed that mixed cluster ions, (C2H5OH)m(H2O)nH+, containing 2~6 molecules of ethanol were abundant and the composition (m-n) of the base peaks were 3-18 and 4-17. The molar ratios of ethanol to water (E/W) for 3-18 and 4-17 are 0.17 and 0.24, respectively, and the E/W ratio calculated from the whole mass spectrum was 0.20. These molar ratios agreed with the ratio (0.21) calculated from the ethanol concentration of the solution, suggesting that the liquid may be an aggregation of these observed clusters. Although the LPI mass spectra of a 20%(v/v) ethanol solution have not yet agreed with the ethanol concentration, these spectra gave nano-scale information about the evaporation processes. In the early stage of evaporation (close to the bulk), the number of ethanol molecules in clusters did not change, but the number of water molecules in clusters decreased rather quickly, resulting in the increase of E/W. Later, the number of ethanol molecules increased during evaporation. It has been well known that the ethanol concentrations in the vapor phase are much higher than those (0~50%) in the liquid phase. LPI-MS gives useful nano-scale information about liquids and evaporation phenomena.
Keywords : iquid ionization mass spectrometry; hydrogen-bonded clusters; ethanol aqueous solution; liquid surface; nano-space science.
Kazuo Uchikura*, Kunio Sakurada, Kou Tezuka** and Katsuya Koike*
*College of Pharmacy, Nihon University, 7-7-1, Narashinodai, Funabashi-shi, Chiba 274-8555
**Comet Co., 1087-131 Kamiaso, Aso-ku, Kawasaki-shi, Kanagawa 215-0021
(Received 24 April 2002, Accepted 5 July 2002)A simple method for the determination of free hydroxyproline (Hyp) and proline (Pro) in serum by HPLC with electrogenerated chemiluminescence detection using tris(2,2'-bipyridine)ruthenium(II) was developed. A serum sample was applied to a centrifugal filter (Microcon, YM-10, Millipore Co., Bedford, MA, U.S.A.) and was centrifuged (14000 rpm, 60 min, 15°C). The filtrate was injected to HPLC. The HPLC conditions were as follows: separation-eluent, 20 mM sodium acetate buffer (pH 4.6), 1 mM Cu2+, 10 mM 1-octanesulfonate-acetonitrile (99:1, v/v); flow rate, 0.5 ml/min; column, Capcell Pak C18 (4.6×150 mm, Shiseido Co., Ltd); detection-reagent solution, 0.3 mM tris(2,2'-bipyridine)ruthenium chloride, 10 mM sulfuric acid, flow rate: 0.3 ml/min, electrogenerated chemiluminescence detector, ECR-2000 (Comet Co., Ltd); controlled current oxidation as 80 µA. Calibration curves plotted the peak area versus Hyp and Pro concentrations. The assay was linear in the concentration range of 0.3~10000 and 0.6~5000 nmol/ml serum for Hyp and Pro, respectively. The recovery was 101% (10 nmol/ml) for Hyp and 103% (50 nmol/ml) for Pro. The intera-assay coefficient of variation was less than 5% for both Hyp and Pro in the linear concentration range. The method was successfully applied to the determination of aged human serum without prior derivatization.
Keywords : hydroxyproline; proline; ruthenium complex; chemiluminescence; HPLC.
Masako Kawarai, Toshihiro Shirasaki* and Kazuko Mizuishi**
*Naka Customer Center, Hitachi Science System Co., Ltd., 882, Ichige, Hitachinaka-shi, Ibaraki 312-8504
**The Tokyo Metropolitan Research Laboratory of Public Health, 3-24-1, Hyakunincho, Shinjuku-ku, Tokyo 169-0073
(Received 7 June 2002, Accepted 22 July 2002)A method for a highly sensitive determination of tributyltin(TBT) and triphenyltin(TPT) in seawater has been developed using GC/pulsed flame photometric detector(PFPD). After deuterated TBT and TPT, as surrogates compounds, were added in seawater, TBT and TPT were derivatized by Grignard reagent propylation. Then, derivatized TBT and TPT were extracted with hexane. PFPD showed high selective and sensitivity for the detection of propyl TBTand TPT. The minimum detection limits, defined as the signality equal to three-times the baseline noise, were 0.078 ng/ml and 0.087 ng/ml, respectively. The mean recoveries at 10 ng/l for water were 84 and 98% for TBT and TPT, respectively, and the mean relative standard deviations were 8.2 and 7.4%, respectively. PFPD made it possible to determine TBT and TPT at less than the ng l-1 level in sea water.
Keywords : GC; pulsed flame photometric detector; FPD; tributyltin; triphenyltin.
Hideaki Kinoshita*
*Department of Human Relations, Kwassui Women's College, 1-50, Higashi-yamate, Nagasaki 850-8515
(Received 30 April 2002, Accepted 26 July 2002)The concentration of fructosamine (FSA) in serum, reflecting the level of blood glucose during two weeks, was determined by an amperometric measurement of H2O2 generated by fructosyl amino acid oxidase (FAOD) after degradation of the serum protein by proteinase K (PK) using a membrane-covered, peroxidase-entrappedand ferrocene-embedded carbon paste electrode. After 20 min degradation of 1/25 diluted serum by 10 U ml-1 PK, FSA was determined by measuring the current increase after the addition of 20 U ml-1 FAOD at pH 9. The ratio of the determined FSA concentration using the current magnitude of N-fructosyl N-Z-lysine (FZL) as a standard to that using diagonostic FSA calibrator as a standard was 0.8. The correlation coefficient between the FSA concentration determined in this method and that by a diagonostic kit based on the spectrometric measurement was 0.97 for 14 serum samples.
Keywords : fructosamine; amperometry; fructosyl amino acid oxidase; proteinase K; glycated protein; hydrogen peroxide.
Tohru Saitoh*, Yuki Yoshida and Chiyo Matsubara**
*Department of Molecular Design and Engineering, Graduate School of Engineering, Nagoya University, Furo, Chikusa, Nagoya 464-8603
**Tokyo University of Pharmacy and Life Science, 1432-1, Horinouchi, Hachioji, Tokyo 192-0392
(Received 30 April 2002, Accepted 2 August 2002)Polymer-mediated extraction based on the thermoresponsive precipitation of poly(N-isopropylacrylamide) (PNIPAAm) was successfully applied to the efficient concentration (ca. 100-folds) of phthalate esters in water. With the use of 0.05 g of polymer against a 10 ml sample, the recoveries of di(2-ethylhexyl)phthalate (DEHP) and dibutylphthalate (DBP) were 98 and 82%, respectively. After extraction, µg/l-levels of DEHP and DBP in tap water, physiological saline, and mineral water samples were successfully determined by HPLC with ultra-violet spectrophotometric detection. The relative standard deviation in the determination of 39 µg/l DEHP (n=5) was 3%.
Keywords : poly(N-isopropylacrylamide); phthalate ester; concentration; HPLC; water sample.
Takashi Okai, Shigeru Terashima and Noboru Imai*
*Geological Survey of Japan/AIST, 1-1-1 Higashi, Tsukuba-shi, Ibaraki 305-8567
(Received 14 June 2002, Accepted 12 July 2002)GSJ has issued many geochemical reference materials, which have been analyzed by many researchers. According to the organization change of GSJ, National Institute of Advanced Industrial Science and Technology, the GSJ geochemical reference materials were charged from April 1, 2001. Therefore, the certified values have to be decided before the distribution of reference materials by collaborative analysis. In this study, collaborative analyses were carried out on the two latest GSJ geochemical reference materials JCu-1 (Copper ore) and JZn-1 (Zinc ore) in 10 laboratories. The analytical data were obtained on 9 components (TiO2, Al2O3, MnO, MgO, CaO, Na2O, K2O, T-Fe, Zn), and Cu (JCu-1) and Pb (JZn-1). ICP-AES and AAS (Na, K) were mainly used. The analytical results agreed comparatively well. In a statistical analysis, the reference values were mainly decided using the robust method. ISO typically recommends that data be submitted from no fewer than 15 laboratories for deciding the certified values; the reference values were considered to be the preliminary certified values.
Keywords : GSJ; JCu-1 copper ore; JZn-1 zinc ore; geochemical reference material; collaborative analysis.
Etsuro Yoshimura*, Zu Dong Liu, Hicham Khodr and Robert C. Hider**
*Applied Biological Chemistry, The University of Tokyo, 1-1-1, Yayoi, Bunkyo-ku, Tokyo 113-8657
**Department of Pharmacy, King's College London, Franklin-Wilkins Building, 150 Stamford Street, London, SE1 9NN, United Kingdom
(Received 14 May 2002, Accepted 28 July 2002)Reagents of commercially available morin contain considerable levels of impurities. Recrystallisation after silica-gel column chromatography yielded morin dihydrate with a purity of 99%. 1H NMR spectrometry indicated that the purity of commercial morin ranged from 30 to 62%. Glycosylated, oxidised and polymerised morin derivatives are the major impurities. Consistent absorption maxima can be obtained when acidified methanol is used as the solvent. Extinction coefficients of 1.59×104 M-1 cm-1 at 354 nm and 0.51 M-1 cm-1 at 490 nm are obtained for the purified morin reagent. It is recommended that the absorption maximum at 354 nm should be used for determination of morin concentration and that the absorption at 490 nm can be used as an index for the presence of impurities.
Keywords : morin; flavonoid; UV-VIS absorption spectrophotometry; 1H NMR.
Yuetsu Danzaki*
*Institute for Materials Research, Tohoku University, 2-1-1, Katahira, Aoba-ku, Sendai 980-8577
(Received 7 March 2002, Accepted 5 August 2002)For the analysis of samples by inductively coupled plasma-optical emission spectrometry (ICP-OES), dissolution of the samples is important. Classical lead assay, chlorination, fluorination and dissolution with acids are difficult for the dissolution of Ir-base alloys. Therefore, fusion with Na2O2 has been used. However, when the alloys are fused with it in a Zr crucible, the crucible is partially dissolved together with Na2O2. The dissolved Zr interferes with the measurements of analytes in the samples by spectral interferences of Zr. To dissolve the crucible as little as possible, it was fused with a mixture of 1 g of NaOH and 2 g of Na2O2; the amount of Zr dissolved was 20~130 mg. Salts given by fusion were dissolved in HNO3-HCl. The analytes in the solution were determined by ICP-OES and the interferences of coexistent elements on the spectral intensities of analytes were corrected by sequential correction method. Good analytical results were obtained for lr-base alloy samples.
Keywords : Ir-Al(-Fe or -Co, -Ni) alloy; fusion with NaOH-Na2O2; ICP-OES.
Yasuto Kashiwagi
Office of Experimental Safety, University of Tsukuba, 1-1-1, Tennodai, Tsukuba, Ibaraki 305-8577
(Awarded by Okayama University dated September 30, 2001)Selective coprecipitations of selenium species and arsenic species in complex high-salts wastewater, followed by graphite-furnace AAS, were developed. Selective separations of selenium species were based on the reductive coprecipitations on tellurium and palladium collector using hydrazinium sulfate, l-ascorbic acid and tin(II) chloride as reducing agents. In particular, the selective reductive coprecipitation of selenite in the presence of selenate was achieved on a 50~500 mg amount of tellurium collector under 1 M HCl for 15 min boiling using l-ascorbic acid and tin(II) chloride, and was achieved on a palladium collector under 0.2 M HCl for 30 min boilng by using hydrazinium sulfate. On the other hand, the selective coprecipitation of inorganic arsenic(III,V) in the presence of organic arsenics was achieved by lanthanum hydroxide coprecipitation at pH 12 or more. Moreover, organic arsenics (dimethylarsinic acid, monometylarsonic acid and p-aminophenylarsonic acid) were quantitatively distilled as chloroarsine compounds under 0.2 M SnCl2, 2.75 M H2SO4 and 4 M HCl. The developed selective determinations of selenium species and arsenic species were satisfactorily applied to real waste water containing ppb levels of selenium and arsenic.
Keywords : graphite-furnace AAS; selenium; arsenic; waste water; coprecipitation.
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