BUNSEKI KAGAKU
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Volume 54, Issue 7
Displaying 1-8 of 8 articles from this issue
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  • Application of Monolithic Silica for Microfluidic Analysis
    Zilin CHEN, Hsueh-Chia CHANG, Toshiyuki HOBO
    2005 Volume 54 Issue 7 Pages 583-592
    Published: 2005
    Released on J-STAGE: November 14, 2005
    DOIhttps://doi.org/10.2116/bunsekikagaku.54.583
    JOURNAL FREE ACCESS
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    It has been known that monolithic porous silica possesses the morphology of a continuous skeleton, micro-scaled through-pore and nano-scaled meso-pore on the skeleton. It is its unique morphology that shows great promise for applications in the fields of analytical chemistry. This paper describes advances in successful applications of monolithic silica to analytical chemistry, achieved in authors’ groups. The authors focused their work on three main subjects regarding monolithic silica: (i) a chemically modified monolithic silica column for chiral separation in capillary electrochromatography and micro-liquid chromatography, (ii) a monolithic enzyme reactor integrated with a biosensor for continuous monitoring (bimolecules), and (iii) an electroosmotic micropump for micro flow analysis and electrospraying.
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  • Development of Temperature-Responsive Chromatography Using Functional Polymers
    Eri AYANO, Hideko KANAZAWA
    2005 Volume 54 Issue 7 Pages 593-603
    Published: 2005
    Released on J-STAGE: November 14, 2005
    DOIhttps://doi.org/10.2116/bunsekikagaku.54.593
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    We developed a novel chromatography system in which temperature controlled separation is achieved by only water as a mobile phase using packing materials modified with a temperature-responsive polymer, poly (N -isopropylacrylamide) (PNIPAAm). The ability of the proposed temperature-responsive chromatography system to separate solutes without using an organic solvent is advantageous from the point of view of maintaining the structure and activity of biologically active substance. Recently, we designed and synthesized copolymers that introduced ion-exchange groups, environmentally-responsive polymers, which respond to temperature and pH. Copolymer-grafted aminopropyl silica beads were used as HPLC packing materials. These separation systems are based on a new concept that the property of the stationary phase surface is altered by external stimuli, such as the pH and temperature. A temperature-responsive chromatography system utilizing PNIPAAm derivatives would be highly useful for peptide and protein separation, since chromatographic separation is performed under mild aqueous mobile phase conditions. Applications to bio-separation in various fields, such as medical and pharmaceutical sciences, is expected.
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Research Paper
  • Determination of Trace Elements in Scallop and Fish Otolith by Instrumental Neutron Activation Analysis Using Anti-Coincidence and Coincidence Counting Methods
    Shogo SUZUKI, Yukiko OKADA, Shoji HIRAI
    2005 Volume 54 Issue 7 Pages 605-612
    Published: 2005
    Released on J-STAGE: November 14, 2005
    DOIhttps://doi.org/10.2116/bunsekikagaku.54.605
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    Trace element concentrations in scallop reference material and fish otolith certified reference materials prepared at the National Institute for Environmental Studies (NIES) of Japan were determined by instrumental neutron activation analysis (INAA). Nine aliquots of scallop sample (ca. 252∼507 mg) and five aliquots of fish otolith sample (ca. 502∼988 mg) and comparative standards were irradiated for a short time (10 s) at a thermal neutron flux of 1.5 × 1012 n cm−2 s−1 (pneumatic transfer) and for a long time (6 h) at a thermal neutron flux of 3.7 × 1012 n cm−2 s−1 (central thimble) in the Rikkyo University Research Reactor (100 kW). The irradiated samples were measured by conventional γ-ray spectrometry using a coaxial Ge detector, and by anti-coincidence and coincidence γ-ray spectrometry with a coaxial Ge detector and a well-type NaI(Tl) detector to determine as many trace elements as possible with high sensitivity. The concentrations of 34 elements of the NIES No.15 scallop referrence material and 16 elements of the NIES No.22 fish otolith CRM were determined. Using the coincidence counting method to determine Se, Ba and Hf, the lower limit of the determination was improved by 2 times compared with the conventional counting method.
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  • Separation Analysis of Amino Modifier Silicone and Dimethylsilicone in Hair Rinses
    Junichi SUGIYAMA, Kosuke TANAKA, Akinori IGARASHI, Kuniaki ADACHI
    2005 Volume 54 Issue 7 Pages 613-619
    Published: 2005
    Released on J-STAGE: November 14, 2005
    DOIhttps://doi.org/10.2116/bunsekikagaku.54.613
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    In this study, we examined a separation analysis method for amino modifier silicones (AMS) and dimethylsilicones (DMS) in hair rinses. Generally, size-exclusion chromatography (SEC) is used for the analysis of silicones. However, SEC cannot separate AMS and DMS by the size-exclusion principle only when the molecular weights are nearly the same. Therefore, we examined the derivatization method of AMS and a separation method for AMS and DMS by SEC-UV-RI (SEC with an ultraviolet detector and a refractive index detector). After an analysis, we were able to detect and determine only the amount of AMS by the derivatization of AMS with N -succinimidyl 4-nitorophenylacetate (SNPA) by using UV (280 nm), and were also able to determine the total silicone (AMS and DMS) amounts by using RI. In addition, the DMS amount was given by subtracting the AMS amount from the total silicone amounts. The recovery rates from model hair rinses were good, and the results were reproducible, except for a portion. Moreover, the chromatograms and molecular weights were in good agreement with the raw materials. In addition, we established a method for calculating the modified rates of AMS by using the analysis method described above.
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Note
Analytical Report
  • Determination of Trace Lead in Plastics by Laser-Induced Plasma Spectroscopy
    Takahiro YASUDA, Mikio KUZUYA
    2005 Volume 54 Issue 7 Pages 637-641
    Published: 2005
    Released on J-STAGE: November 14, 2005
    DOIhttps://doi.org/10.2116/bunsekikagaku.54.637
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    A quantitative analysis of trace lead in plastics was carried out with laser-induced plasma spectroscopy (LIPS). A Q-switched Nd:YAG laser (pulse energy, 90 mJ; pulse width, 10 ns; repletion rate, 10 Hz) was focused on plastic samples in an argon atmosphere, and the emission characteristics of the laser-induced plasma were investigated by changing the argon pressure from atmospheric pressure to 1 Torr. The experimental result showed that the emission intensity of the analysis line (Pb I 405.78 nm) was maximized at a pressure of around 10 Torr. The determination of trace lead in the standard plastic samples (polyethylene and polyvinyl chloride) was carried out in argon at 10 Torr. In the analysis of polyvinyl chloride, time-resolved spectroscopy was used to reduce the effect of the spectral interference with the matrix as well as the background. Linear calibration curves were obtained with detection limits of several tens ppm. The LIPS method was applied to industrial samples.
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