Vol. 51 No. 5
May, 2002
Nobuo Nakano, Yasuhiro Terauchi, Tetsuya Kawabe* and Kunio Nagashima**
*Riken Keiki Co., Ltd., 2-7-6, Azusawa, Itabashi-ku, Tokyo 174-8744
**Faculty of Engineering, Kogakuin University, 2665-1, Nakanocho, Hachioji-shi, Tokyo 192-0015
A porous cellulose tape impregnated with a processing solution that includes sodium nitroprusside dihydrate, zinc formate, glycerin and methanol is a highly sensitive means of detecting sulfur dioxide in air. When the sample including sulfur dioxide was passed through the tape, sulfur dioxide was absorbed on the surface of the tape, and reacted with zinc nitroprusside to form a stain. The intensity of the stain was proportional to the concentration of sulfur dioxide at a constant sampling time and flow rate, and it could be recorded by measuring the intensity of reflecting light(555 nm). The detection limit was 0.03ppm for sulfur dioxide with a sampling time of 20 s and a flow rate of 400 ml/min. Reproducibility tests showed that the relative standard deviation of response(n=8) was 0.97% for 2 ppm sulfur dioxide (TLV-TWA for sulfur dioxide is 2 ppm). No interference was observed from acetylene(0.5%), ethanol(1 vol.%), acetone(1 vol.%), trichloroethylene(1 vol.%), carbon dioxide(99.9 vol.%), carbon monoxide(103 ppm), hydrogen chloride gas(5 ppm), ammonia(40 ppm),nitrogen dioxide(50 ppm), hydrogen sulfide(20 ppm).
Keywords : sulfur dioxide; monitoring tape; sensitive tape for sulfur dioxide; zinc nitroprusside.
Hideo Hayashi, Tomokazu Tanaka and Masataka Hiraide*
*Department of Molecular Design and Engineering, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8603
(Received 13 February 2002, Accepted 1 April 2002)Although ICP-MS offers a powerful multielement analytical method, the mass spectral interference due to argon often becomes a serious problem. For example, 40Ar16O+, 40Ar35Cl+ and 40Ar2+ interfere with the determination of 56Fe+, 75As+ and 80Se+, respectively. Therefore, we replaced argon by helium to develop an interference-free ICP-MS, and successfully detected iron and arsenic in aqueous solutions. Some weak background peaks, however, were still generated at m/z 79~82 and disturbed the determination of traces of bromine (79Br+) and selenium (80Se+). In the present work, it was found that these peaks originated from the copper interface by a secondary discharge. They were assigned to 63Cu16O+, 63Cu16OH+, 65Cu16O+ and 65Cu16OH+. The nickel interface caused more serious background at m/z 50~100. On the other hand, no spectral interference was observed over a wide m/z range when the interface was constructed from aluminum. The optimized helium ICP-MS was used for the determination of traces of bromine and selenium in water. A 5 µl volume of a sample was placed and heated electrothermally on a tungsten filament. The resulting vapor was introduced into the helium plasma for a mass spectrometric analysis. The relative standard deviation of the signals (10 ng ml-1, n = 10) was approximately 10 %. The detection limits based on 3σ were 0.2 ng ml-1 for Br and 0.09 ng ml-1 for Se, which were lower compared with the conventional argon ICP-MS (Br 20 ng ml-1, Se 0.25 ng ml-1).
Keyword : low-pressure helium ICP-MS; electrothermal vaporization; selenium; bromine; mass spectral interference.
Norio Manabe, Hiroaki Minami, Yoshimitu Yokota, Fumiaki Okuda and Yuuya Uegomori*
*Suzuka Research Laboratory, Sumitomo Wiring Systems Co., Ltd., 1820, Nakanoike, Mikkaiti, Suzuka-shi, Mie 513-8631
(Received 2 November 2001, Accepted 4 March 2002)After a pretreatment of methanol added thermal decom-position, GC was applied to the simultaneous determi-nation of a popular amino triazole-type copper deactivator, 3-(N-salicyloyl) amino-1,2,4-triazole (CDA-1, abbreviation: CDA) and a hindered phenol-type antioxidant, tetrakis[methylene 3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate]methan (Irganox1010, abbreviation: IRG). Their contents for several polypropylene standard samples, prepaired by adding 0.2 to 1.0 wt% of each CDA and IRG, were determined based on the peak intensity of the components decomposed with methanol at 220°C for 1.5 h in a sealed pyrex tube. The relative standard deviations (RSD) were 3.1 to 5.9%. This technique can be used to determine the CDA andIRG contents simultaneouly and to evaluate the degradation process of polymer materials.
Keywords : GC-simultaneous determination; methanol decomposition; copper deactivator; antioxidant; degradation.
Takeshi Yamane*, Takashi Murayama**, Toshihisa Maruta and Takaji Kawai***
*Department of Chemistry, Faculty of Education and Human Sciences, Yamanashi University, 4-4-37, Takeda, Kofu-shi, Yamanashi 400-8510
**Jyousai High School, 1-9-1, Shimoiida, Kofu-shi, Yamanashi 400-0064
***Analytical Division, Taiheiyo Consultant Co., Ltd., 3-8-5, Misaki-Chou, Chiyoda-ku, Tokyo 101-0061
A flow-injection system (FIA) is described for the simple and rapid determination of chromium(VI) in a leached solution from soil, which allows to one simultaneously measure the signal responses due to chromium(VI) and a blank. The method utilizes a color-forming reaction of CrVI with diphenylcarbazide (DPC). The system is based on the synchronized injection of a large volume of sample solution and a small volume of a modifying reagent solution (ascorbic acid for reducing CrVI to CrIII) into separate streams, which are then merged at a confluence point. Thus, two reaction zones, for CrVI and for the blank, in a single sample plug are provided, and then mixed down stream with a stream of DPC for spectrophotometric detection. The variables related to such a reaction and which provide two reaction zones were studied in detail, and optimal conditions and manifold were established. The calibration graph was rectilinear in the range of 0.005~0.2 mg/l CrVI. A relative standard deviation (n=5) of 1.1% was obtained for the analysis of 0.05 mg/l CrVI solution. The estimated limit of determination was 0.005 mg/l. An analysis rate of 10/h is estimated. The results for analysis of various solutions leached from soil by the proposed FIA system correspond well with those by the standard batchwise method. The proposed FIA system can afford a rapid and simple analysis: only 6 min is required for analytical measurement after sample injection, and no complicated manual operation is involved.
Keywords : flow injection analysis; diphenylcarbazide; spectrophotometric detection; hexavalent chromium leached from soil; leaching test.
Shigeru Terashima, Takashi Okai and Noboru Imai*
*Geological Survey of Japan (GSJ), National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba Central 7, 1-1-1, Higashi, Tsukuba-shi, Ibaraki 305-8567
(Received 18 February 2002, Accepted 14 March 2002)A simple and sensitive method by AAS using either a combination of hydride generation and quartz cell (HG-QC) atomizer or solvent extraction and graphite furnace (SE-GF) atomizer has been investigated for the determination of Bi in a great variety geological reference materials. Their advantages were considered. A sample of 0.1 to 0.5 g was decomposed with HNO3, HClO4 and HF, and dissolved by heating with diluted HCl. After the addition of ascorbic acid and thiourea, bismuth hydride was generated with 1% sodium tetrahydroborate and 2 M HCl using an automated hydride generator. The method of SE-GFAAS was adopted for samples with low Bi contents. The samples were decomposed by the above-mentioned method, and Bi was extracted as the iodide into 1 ml of n-butyl acetate from a 0.9 M HClO4-0.003 M NaI solution containing ascorbic acid and Au as a matrix modifier. The limit of detection was 5 ng g-1 by HG-QCAAS, and 0.8 ng g-1 by SE-GFAAS for 0.5 g test potions. This method was successfully applied to the determination of Bi in 50 international geological reference materials.
Keywords : bismuth; hydride generation AAS; organic solvent extraction; graphite furnace AAS; geological reference material.
Hiroyuki Noda*, Tsuneyoshi Goto**, Hiroaki Ohya and Hitoshi Kamada*
*Institute for Life Support Technology, Yamagata Public Corporation for the Development of Industry, 2-2-1, Matsuei, Yamagata 990-2473
**Yamamoto Co., Ltd., 4004, Oinomori, Tendo-shi, Yamagata 994-8611
Keywords : fluorescence imaging; brown rice; freshness.
Hideki Kuramitz
Division of Material Science, Graduate School of Environmental Earth Science, Hokkaido University, Sapporo, Hokkaido 060-0810
(Awarded by Hokkaido University dated December 25, 2001)Some simple methods for an electrochemical binding assay for protein-ligand like avidin-biotin and lectin-sugar were developed. In a homogeneous binding assay based on the use of an electroactive label, following methods are proposed to obtain a sensitive electrochemical response. 1) In order to obtain an amplified electrode response without an enzyme label, an electron-transfer mediator was used as a label. 2) In order to use anodic stripping voltammetry for the sensitive detection of metal, a ligand labeled with a complex reagent was applied to the binding assay. 3) An accumulation of ligand to an ion exchange membrane electrode was investigated using a ligand labeled with a cationic electroactive molecule. 4) A highly sensitive detection of an electroactive labeled ligand was attempted by the potential regulating accumulation on a plain glassy carbon electrode. In a heterogeneous binding assay based on a technique without a label, some hydrophilic electroactive compounds were used as a redox marker to evaluate the protein-ligand interaction. A sensitive and selective binding assay could be achieved by monitoring the change in the electrode response of the redox marker. In addition, a development of screening method for endocrine disrupting chemicals using 17β-estradiol labeled with an electroactive compound was attempted. These electrochemical binding assays do not require a separation procedure prior to any measurements. Therefore, dynamic monitoring for the formation of the protein-ligand complex is possible.
(Received 26 February, 2002)Keywords : electrochemical binding assay; protein-ligand interaction; avidin-biotin; lectin-sugar; redox marker; endocrine disrupting chemicals.
Hong-Bing Hou
Musashi Engineering Corporation, 60, Sekitori, Ueda-machi, Toyohashi-shi, Aichi 441-8134
(Awarded by Saitama University dated March 24, 2000)Simple methods for the chemical speciation of antimony and organotin compounds were developed by atomic spectroscopy. Antimony was determined by inductively coupled plasma atomic emission spectrometry (ICP-AES) and high-resolution inductively coupled plasma mass spectrometry (ICP-MS) with a hydride generation technique. Stibine generated with sodium tetrahydroborate(III) (SBH) in a mixing coil was separated from solution with a spiral tube in a closed vessel. The antimony contents of River Arakawa were determined by the present methods. Antimony(III) and antimony(V) were determined differentially by ICP-AES and ICP-MS. Antimony(III) was determined at pH 5.5, while the total antimony was determined at pH 1.0 using potassium iodide as a prereductant. It was found by ICP-MS that the antimony(III) contents of River Arakawa increased while the antimony(V) contents decreased while descending down-stream. Tributyltin and triphenyltin in fish were determined by gas chromatography-atomic absorption spectrometry (GC-AAS) with hydride generation. Fish meat was homogenized in a hydrochloric acid solution of 8-quinolinol. The chlorides in fish were extracted into hexane. After the solvent had been converted to 2-propanol, the solution was applied to a Bondesil SCX solid sorbent. The organotin compounds were eluted with a methanol solution of hydrochloric acid and determined by GC-AAS after hydradization with SBH. The organotin chlorides are supposed to form ion-associates with 8-hydroquinolinium cation in a hydrochlic acid medium.
(Received March 6, 2002)Keywords : ICP-AES; ICP-MS; hydride generation; antimony(III); antimony(V); river water; GC/AAS; tributyltin; triphenyltin; fish.
Yong-Lai Feng
National Research Council of Canada, 1500, Montreal Road, Ottawa, K1A 0R9, Canada
(Awarded by Saitama University dated March 24, 2000)Tin was determined by inductively coupled plasma atomic emission spectrometry (ICP-AES) and high resolution-inductively coupled plasma mass spectrometry (ICP-MS) with a hydride generation technique. Stannane generated with sodium tetrahydroborate(III) (SBH) was separated from solution with a spiral tube in a closed vessel. The tin content in marine materials was determined by the present methods. Antimony(III) and antimony(V) were detemined by ICP-AES or ICP-MS using the pre-reduction of antimony with L-cycteine. Also, arsenic(III) and arsenic(V) were determined by ICP-MS combined with the pre-reduction of arsenic. Tributyltin and triphenyltin in marine sediments were determined by gas chromatography-atomic absorption spectrometry (GC-AAS) with hydride genation. The chlorides in sediments spiked with a hydrochloric acid solution of 8-quinolinol were extracted in toluene. After the solvent had been converted to ethanol, it was applied to a Bondesil SCX. The organotin compounds were eluted with a methanol solution of hydrochloric aced and tetermined by GC-AAS after hydridization.
(Received March 6, 2002)Keywords : ICP-AES; ICP-MS; hydride generation; tin; antimony(III); antimony(V); arsenic(III); arsenic(V); GC/AAS; tributyltin; marine materials.
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