BUNSEKI KAGAKU
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Volume 52, Issue 4
Displaying 1-10 of 10 articles from this issue
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Accounts
  • Thermoresponsive polymer-mediated preconcentration for trace analysis
    Tohru SAITOH, Chiyo MATSUBARA, Masataka HIRAIDE
    Article type: Accounts
    2003 Volume 52 Issue 4 Pages 221-229
    Published: 2003
    Released on J-STAGE: September 05, 2003
    DOIhttps://doi.org/10.2116/bunsekikagaku.52.221
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    Simple and rapid preconcentration techniques using themoresponsive polymers were developed for the determination of traces of organic and inorganic constituents in aqueous solutions. Thermoresponsive polymers, including poly(N-isopropylacrylamide) and poly(vinylmethyl ether), are water-soluble at room temperature, but become sparingly soluble above their critical solution temperatures (ca. 3°C) to form gum-like precipitates. Hydrophobic organic compounds in aqueous solutions were effectively collected on the polymer precipitates, depending on their hydrophobic properties. On the other hand, hydrophilic components remained in the bulk aqueous solutions. Because the polymer phase was highly condensed, the concentrations of analytes were easily increased 100-fold. Hydrated metal ions were converted into hydrophobic chelates with 8-hydroxyquinoline or ammonium pyrrolidine dithiocarbamate, which were successfully incorporated in the polymer phase. Water-soluble charged metal chelates were also concentrated by using adequate counter ions. After dissolving the polymer phase in a small amount of organic solvent, the solution was directly analyzed by HPLC, graphite furnace AAS or ICP-MS. Polymer-mediated preconcentration techniques can also be applicable to the clarification of industrial wastewater.
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Research Papers
  • Separation and determination of chromium (III) and chromium (VI) in water samples by inductively coupled plasma atomic emission spectrometry after collecting these species on CaHPO4 powder
    Tomohiro NARUKAWA, Yukitoki MORITA, Takeshi OTSUKA, Kenneth W. RILEY, ...
    Article type: Research Papers
    2003 Volume 52 Issue 4 Pages 231-238
    Published: 2003
    Released on J-STAGE: September 05, 2003
    DOIhttps://doi.org/10.2116/bunsekikagaku.52.231
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    A simple method for the separation and determination of chromium (III) and chromium (VI) in water samples using a powder of calcium compounds was examined. It was found that CaO, CaCO3, CaSO4 and CaHPO4 are applicable to the collection of chromium (III) over the range of pH 8 to 13. To a 100 ml sample solution (pH 10) containing less than 0.25 mg of chromium (III) and chromium (VI), 100 mg of CaHPO4 powder was added, and the mixture was stirred for 10 min by a stirrer. Then, chromium (III) in the sample solution was collected on CaHPO4 powder. The mixture was separated into CaHPO4 containing chromium (III) and a liquid phase containing chromium (VI) through a membrane filter by vacuum filtration. The liquid phase containing chromium (VI) was added to 1 g of N2H6SO4 for the reduction to chromium (III). We found that chromium (VI) was reduced 100% to chromium (III) within 3 min by N2H6SO4. Similarly, the chromium (III) that was reduced from chromium (VI) was collected on CaHPO4 powder. The obtained CaHPO4 powder samples were dissolved with hydrochloric acid (final concentration, 2 mol l−1 HCl) and prepared to a constant volume (25 ml). The concentrations of chromium in the obtained solutions were determined by ICP-AES. When this method was used, the detection limits (3σ) from a 500 ml sample solution was 0.3 μg l−1. The proposed method has been applied to several water samples.
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  • Method of cluster making for a multivariate analysis
    Toshiyuki MITSUI, Syuji OKUYAMA, Minemasa HIDA
    Article type: Research Papers
    2003 Volume 52 Issue 4 Pages 239-244
    Published: 2003
    Released on J-STAGE: September 05, 2003
    DOIhttps://doi.org/10.2116/bunsekikagaku.52.239
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    A qualitative analysis involving multivariate analysis does not have a clear standard on which to base the results. Any difference in the qualitative analytical results by individual analysts raises doubt concerning the reliability of the qualitative analysis in which a multivariate analysis is used. The qualitative analysis for identification is evaluated as follows. First, the obtained 5∼15 data from measuring one sample is added to unknown cluster belonging to a sample (unknown sample) to identify the difference, and calculated by a principal component analysis for removing the outlier in unknown samples. Next, the cluster analysis is examined. When the Euclid distance of the unknown sample cluster is smaller than that of the data cluster, the unknown sample cluster is judged as one cluster. Next, the relations between the unknown samples are calculated by soft independent modeling of the class analogies method (SIMCA method) based on the result of the cluster analysis. The unknown samples are calculated by a principal component analysis based on the result of the SIMCA method. Finally, the cluster belonging of the individual unknown sample is specified from the result of the cluster analysis and the principal component analysis. The unknown samples are accurately made into a cluster by such a method.
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  • Study of a metal-coated hollow-fiber membrane electrode for sugar detection by an amperometric detection method
    Osamu IGARASHI, Masayuki UTO, Sadanobu INOUE, Suwaru HOSHI, Toshitsugu ...
    Article type: Research Papers
    2003 Volume 52 Issue 4 Pages 245-251
    Published: 2003
    Released on J-STAGE: September 05, 2003
    DOIhttps://doi.org/10.2116/bunsekikagaku.52.245
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    A metal-coated hollow-fiber membrane electrode (MCHE) has been applied as a working electrode of an electrochemical detector in high-performance liquid chromatography. In this paper, the structure of the detector was studied for obtaining a high sensitivity and sharp response on a model of electrochemical oxidation of glucose in an alkaline solution. The MCHE has a tubular structure with an inner volume that broadens the output signal peak with a wide distribution of the specimen concentration due to a residual sodium hydroxide solution. An analysis of the dead volume of the present detector revealed that the volume of holes in the membrane wall was almost equal to the inner volume of the electrode. Only the inside metal layer of the MCHE was made active for electrochemical detection in order to reduce the effect of the dead volume of the membrane holes. The detection limit and the half-width of the peak were down to 0.69 pmol and 1.8 s, respectively.
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Technical Papers
  • Simplified determination of VOCs emitted from painted building materials using a headspace-vial as a chamber
    Yoshikazu SUGESAKA, Tsutomu MATUURA, Susumu AOYAMA, Ken YAMAMOTO
    Article type: Technical Papers
    2003 Volume 52 Issue 4 Pages 253-257
    Published: 2003
    Released on J-STAGE: September 05, 2003
    DOIhttps://doi.org/10.2116/bunsekikagaku.52.253
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    A simplified analytical method using a milliliter-sized vial, which could be used to estimate the concentration of volatile organic compounds (VOCs) at room atmosphere emitted from each source, such as a building material, adhesive or paint, was established. When the concentration of VOCs in real living space was supposed, the result of this small-sized measurement could be a good reference. The sensitivity of GC/MS on an air sample measurement was sufficient for a direct analysis. For a small-sized sample measurement, although there was a problem of VOCs emission from each face, except for the surface, which should be evaluated, its influence could be reduced by masking any unnecessary faces using sealing materials, such as an aluminum tape.
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  • Fractional determination of sodium chondroitin sulfate/hydroxypropylmethylcellulose mixture using Alucian Blue 8GX
    Manabu HATTORI, Junya ARITA, Nobuhito TABUCHI, Shigeyuki KOIKE, Hirosh ...
    Article type: Technical Papers
    2003 Volume 52 Issue 4 Pages 259-263
    Published: 2003
    Released on J-STAGE: September 05, 2003
    DOIhttps://doi.org/10.2116/bunsekikagaku.52.259
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    Using Alucian Blue 8GX (AB), a simple fractional determination method was developed for sodium chondroitin sulfate (ChS-Na) and hydroxypropylmethylcellulose (HPMC) respectively in a drug. From a sample solution containing both ChS-Na and HPMC, ChS-Na was precipitated selectively as the ChS-Na-AB complex under a low-pH condition. After dissolution of the ChS-Na-AB complex in an alkali solution, ChS-Na was determined by the absorbance at 615 nm. The supernatant of the sample solution was subjected to gel permeation chromatography (GPC). The amount of HPMC was determined by the peak height of HPMC. These methods have safty, high-specificity and high-repeatability. These methods are therefore useful for drugs which contain both acidic mucopolysaccharide and a non-ionic polymer.
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Notes
  • Development and evaluation of reaction gas chromatograph as a calibration method using an index compound
    Takuro WATANABE, Kenji KATO, Nobuhiro MATSUMOTO, Tsuneaki MAEDA
    Article type: Notes
    2003 Volume 52 Issue 4 Pages 265-268
    Published: 2003
    Released on J-STAGE: September 05, 2003
    DOIhttps://doi.org/10.2116/bunsekikagaku.52.265
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    In order to realize a technique that serves as a calibration method using an index compound, reaction gas chromatography was examined. An index compound represents a group which includes many compounds; compounds in this group can be calibrated using the index compound. The gas chromatograph/micro reactor/mass spectrometer (GC/MR/MS) consists of a capillary gas chromatograph/mass spectrometer and a micro reactor. By using the MR, alkenes and alkynes were transformed to alkanes having the same carbon skeleton. Ethylene in a cylinder was determined using ethane as an index compound. The results showed good agreement with a reference value. The hydrodechlorination of chlorobenzenes was examined. Chlorobenzene in a solution was determined by using benzene as an index compound. The experimental results and reference concentration showed a good agreement. The efficacy of this technique was demonstrated with these results.
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  • Determination method of serum albumin using a Bromocresol Green solution and a Bromocresol Purple solution containing no detergent as a color reagent
    Yuji SUZUKI
    Article type: Notes
    2003 Volume 52 Issue 4 Pages 269-273
    Published: 2003
    Released on J-STAGE: September 05, 2003
    DOIhttps://doi.org/10.2116/bunsekikagaku.52.269
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    Various detergents have been used in the dye-binding method for the determination of human serum albumin to prevent precipitation of the serum protein. However, there is problem that some detergents contained in the color reagent cause water pollution. Thus, the author studied the dye-binding method for determining human serum albumin using a Bromocresol Green (BCG) solution and a Bromocresol Purple (BCP) solution containing no detergent as a color reagent. The precipitation of serum protein occurred in the pH range of 3.8 to 4.2 for BCG, and 4.2 to 4.6 for BCP. Thus, pH 3.4 and pH 5.2 were selected for the pH of the BCG and BCP color reagents, respectively. In measuring a number of patients’ sera, the precipitaion of serum protein was not observed at all in both BCG and BCP color reagents containing no detergent. The measurement values obtained by the proposed BCG method correlated very well with those by the conventional BCG method (r = 0.997, y = 0.983x−0.807, n = 90) and the conventional BCP method (r = 0.984, y = 0.849x + 5.57, n = 90). The measurement values obtained by the proposed BCP method correlated well with those by the conventional BCP method (r = 0.961, y = 0.809x + 7.55, n = 90) and the conventional BCG method (r = 0.948, y = 0.913x + 2.39, n = 90). The mean values of the proposed BCG and BCP methods and the conventional BCG and BCP methods were 36.6, 37.2, 38.1 and 36.6 g/l, respectively.
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  • Determination of halogens by low-pressure helium ICP-MS
    Hideo HAYASHI, Yasuhisa HARA, Tomokazu TANAKA, Masataka HIRAIDE
    Article type: Notes
    2003 Volume 52 Issue 4 Pages 275-278
    Published: 2003
    Released on J-STAGE: September 05, 2003
    DOIhttps://doi.org/10.2116/bunsekikagaku.52.275
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    A low-pressure ICP formed with helium has been utilized as an ion source for MS, which is capable of providing information about traces of iron, arsenic and selenium without any interference from ArO+, ArCl+ and Ar2+, respectively. The present paper describes the application of a novel ICP for the determination of fluorine, chlorine, bromine and iodine, because the ionization of these halogens is highly suppressed in the case of conventional argon ICP (e.g., 9×10−4% for fluorine). A 5 μl aliquot of an aqueous sample was placed on a looped tungsten filament and heated electrothermally at ca. 2500°C . The resulting sample vapor was transported to the ICP with a stream of helium. The analytes (19F+, 35Cl+, 79Br+ and 127I+) were then determined by a quadrupole mass analyzer. The detection limits (ng ml−1, based on 3σ) were 23 (F), 2.4 (Cl), 0.13 (Br) and 0.05 (I), which were much better than those of argon ICP. The absolute detection limits using 5 μl of a sample reached to the sub-picogram range. Especially, the detectability for fluorine was significantly improved, which allowed a direct determination of fluorine at the ng ml−1 level in water.
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Technical Letters
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