Analytical Sciences
Online ISSN : 1348-2246
Print ISSN : 0910-6340
ISSN-L : 0910-6340
Volume 29 , Issue 3
Showing 1-17 articles out of 17 articles from the selected issue
Rapid Communications
Original Papers
  • Ryo ISHII, Ryuichi NAGANAWA, Masateru NISHIOKA, Taka-aki HANAOKA
    Type: Original Papers
    2013 Volume 29 Issue 3 Pages 283-289
    Published: March 10, 2013
    Released: March 10, 2013
    JOURNALS FREE ACCESS
    We have used novel microporous biphenylene-pillared layered silicates as receptors in a quartz crystal microbalance (QCM) for sensing toluene vapors. The silicate was successfully coated on a QCM electrode modified with 2-aminoethanethiol. The resultant electrode showed quantitative frequency responses due to enhanced adhesion between the silicate and the electrode. The silicate-coated electrodes also performed better than polystyrene-coated electrodes in terms of both sensitivity and reproducibility of the responses for toluene vapors exposures because the silicate has an organically-modified open-framework structure with a high surface area. In addition, the electrodes revealed the higher sensitivity for toluene vapors than those for alcohol vapors, suggesting selectivity toward sensing toluene vapors probably due to the π–π stacking interaction between biphenylene units and toluene molecules. Hence, we anticipate that the materials are promising to be used as receptors in QCM devices for sensing aromatic vapors.
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  • Kenji OHISHI, Tetsuo SAKAMOTO, Jiro SAIKAWA, Naoya ISHIGAKI, Koji TOJO ...
    Type: Original Papers
    2013 Volume 29 Issue 3 Pages 291-295
    Published: March 10, 2013
    Released: March 10, 2013
    JOURNALS FREE ACCESS
    Laser post-ionization of sputtered molecules by pulsed Ga focused ion-beam (Ga-FIB) bombardment was examined for the detection and imaging of polycyclic aromatic hydrocarbons (PAHs) on particles. As model samples, pyrene and pelyrene adsorbed on TiO2, blended regents of pyrene and n-heneicosan were used. The TiO2 particle size was selected to be several micro-meters. Laser light and Ga-FIB were synchronized with each other. The repetition rate synchronized with Ga-FIB was 1 kHz for pyrene analysis and 2 kHz for perylene, respectively. The laser wavelength was set to 266 nm. The wavelength was a generated fourth harmonic of a Nd:YAG DPSS (diode-pumped solid-state) micro-chip laser (UV microchip laser). By using a UV microchip laser, laser-SNMS (laser post-ionized sputtered neutral mass spectrometry) analysis and imaging were performed. The imaging of pyrene (m/z = 202, C16H10) and perylene (m/z = 252, C20H12) has been successful. Both the scanning ion microscopy image of TiO2 and the PAHs image in laser-SNMS analysis were well-fitted with each other.
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  • Hiroki KINOUCHI, Masako ONISHI, Hiroshi KAMIMORI
    Type: Original Papers
    2013 Volume 29 Issue 3 Pages 297-301
    Published: March 10, 2013
    Released: March 10, 2013
    JOURNALS FREE ACCESS
    In the present study, we developed an assay of interactions of daptomycin with four model lipid membranes that mimicked mammal cell membranes and gram-positive and negative bacteria membranes. We also analyzed the binding kinetics of the gram-positive bacteria membranes using surface plasmon resonance (SPR). Daptomycin showed a higher affinity for the model gram-positive bacteria membrane than those of the model mammal cell and gram-negative bacteria membranes, and the binding selectivity of daptomycin in the presence of calcium could be represented by this SPR system. This method also showed reproducible immobilization of model liposome membranes on the sensor chip, and had a desirable repeatability in the analysis of the binding kinetics to the model gram-positive bacteria membranes. The results demonstrate that this newly established SPR method could be a valuable tool for predicting the binding characteristics of antimicrobial agents to lipid membranes.
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  • Ali A. ENSAFI, Elaheh KHODDAMI, Behzad REZAEI
    Type: Original Papers
    2013 Volume 29 Issue 3 Pages 303-309
    Published: March 10, 2013
    Released: March 10, 2013
    JOURNALS FREE ACCESS
    In this paper, we describe a new combination method based on polytetrafluorethylene (PTFE) film-based liquid three-phase micro extraction coupled with differential pulse voltammetry (DPV) for the micro extraction and quantification of atorvastatin calcium (ATC) at the ultra-trace level. Different factors affecting the liquid-three phases micro extraction of atorvastatin calcium, including organic solvent, pH of the donor and acceptor phases, concentration of salt, extraction time, stirring rate and electrochemical factors, were investigated, and the optimal extraction conditions were established. The final stable signal was achieved after a 50 min extraction time, which was used for analytical applications. An enrichment factor of 21 was achieved, and the relative standard deviation (RSD) of the method was 4.5% (n = 4). Differential pulse voltammetry exhibited two wide linear dynamic ranges of 20.0 – 1000.0 pmol L−1 and 0.001 – 11.0 μmol L−1 of ATC. The detection limit was found to be 8.1 pmol L−1 ATC. Finally, the proposed method was used as a new combination method for the determination of atorvastatin calcium in real samples, such as human urine and plasma.
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  • Masaru MATSUGAMI, Kenta FUJII, Takeshi UEKI, Yuzo KITAZAWA, Yasuhiro U ...
    Type: Original Papers
    2013 Volume 29 Issue 3 Pages 311-314
    Published: March 10, 2013
    Released: March 10, 2013
    JOURNALS FREE ACCESS
    It has been established that poly(benzyl methacrylate) in a room-temperature ionic liquid, 1-ethyl-3-methylimidazolium bis(trifluoromethanesulfonyl)amide ([C2mIm+][TFSA]), exhibits lower critical solution temperature (LCST)-type phase separation. In this work we investigated the solvation structure of benzyl methacrylate monomer in the ionic liquid by using high-energy X-ray diffraction with the aid of a molecular dynamics simulation. It was found that the C2mIm cation orderly distributes above and below a benzyl group within benzil methacrylate (BnMA), while the TFSA anion distributes around the equatorial position of the benzyl group where no cation distribution is found, with a weak interaction between TFSA and BnMA. The relationship between specific solvation and the LCST phase separation mechanism was considered at the molecular level.
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  • Kanji MIYABE, Yuko MATSUMOTO, Nobuho ANDO, Yumi TERATANI
    Type: Original Papers
    2013 Volume 29 Issue 3 Pages 315-323
    Published: March 10, 2013
    Released: March 10, 2013
    JOURNALS FREE ACCESS
    It was demonstrated that the peak parking-moment analysis (PP-MA) method could be used as an alternative for the measurement of pore diffusivity (Dp) in porous packing materials for HPLC. The value of Dp of uracil was measured by the PP-MA method under non-retained conditions in the RPLC systems using C18-silica gel particles and C18-silica monolith as the stationary phase and 70 vol% methanol as the mobile phase. The value of Dp was compared with that derived by the pulse response-moment analysis (PR-MA) method under the same conditions. The Dp values of uracil derived by the PP-MA and PR-MA methods were almost in agreement with each other. Because the PP-MA and PR-MA methods have complementary characteristics as experimental methods for studying mass transfer kinetics, it is expected that the combination of the two methods would lead to an effective strategy for the measurement of Dp in porous separation media for HPLC.
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  • Zhi LI, Mengying HOU, Shasha BAI, Chun WANG, Zhi WANG
    Type: Original Papers
    2013 Volume 29 Issue 3 Pages 325-331
    Published: March 10, 2013
    Released: March 10, 2013
    JOURNALS FREE ACCESS
    In this paper, a sensitive analytical method for four fungicides (procymidone, folpet, vinclozolin and ditalimfos) in environmental water and juice samples was developed by using magnetic solid-phase extraction (MSPE) with magnetic graphene nanocomposite (G-Fe3O4) as the adsorbent, followed by determination with gas chromatography and electron capture detection. Parameters such as the amount of G-Fe3O4, extraction time, ionic strength and pH of the sample solution, desorption solvent and desorption time were optimized. Under the optimum conditions, the enrichment factors of the method for the analytes were in the range from 1495 to 1849. The limits of detection for the fungicides ranged from 1.0 to 7.0 ng L−1. The recoveries of the method for the analytes were in the range from 79.2 to 102.4%. The developed G-Fe3O4-MSPE method was simple and efficient for the extraction and determination of the four fungicides in water and grape juice samples.
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  • Emi OTSU, Mayumi ETOU, Hironori OHASHI, Ikuko NISHIDA, Shuquin BAI, Yo ...
    Type: Original Papers
    2013 Volume 29 Issue 3 Pages 333-337
    Published: March 10, 2013
    Released: March 10, 2013
    JOURNALS FREE ACCESS
    In order to estimate the absolute size distribution of polysilicic acid particles in geothermal waters, the distribution coefficient (Kav) of gel permeation chromatography (GPC) for polysilicic acid particles and the hydrodynamic radius for the same polysilicic acid particles from Dynamic Light Scattering (DLS) are combined to quantify the particle size. From the combination, a quantitative relationship between the Kav from GPC and the hydrodynamic radius for polysilicic acid from DLS was built up. Using this relationship, the change in particle size of polysilicic acid formed during the polymerization of silicic acid at pH 8 and 9 (initial silicic acid concentration: 800 ppm as SiO2) was examined. The result showed that polysilicic acid grew to 500 and 1000 nm by 5 h at pH 9 and 8, respectively. It was found that aluminum affects the growth of polysilicic acid particles, and that the effect depends on the pH. The proposed method in this study has been proved to be valid to measure the size of polysilicic acid during the polymerization of silicic acid in solutions with relatively low silicic acid concentration, such as geothermal water.
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  • Nantana NUCHTAVORN, Marketa RYVOLOVA, Fritz BEK, Mirek MACKA, Chutima ...
    Type: Original Papers
    2013 Volume 29 Issue 3 Pages 339-344
    Published: March 10, 2013
    Released: March 10, 2013
    JOURNALS FREE ACCESS
    Capillary electrophoresis (CE) coupled with capacitively-coupled contactless conductivity (C4D) and fluorescence (FD) detectors and chip-CE for monitoring of nicotine and cotinine derivatization was demonstrated. Separation of the substrates and intermediates could be achieved by CE-C4D in 7 min (Rs > 2.7) using 45 mM acetic acid (pH 3.0) and this system was applied to detect the intermediate formation. Final fluorescent products could be analyzed by micellar electrokinetic chromatography (MEKC-FD) in 5 mM borate buffer (pH 9.0) containing 10 mM sodium dodecylsulfate (SDS) (%RSD < 3.00%). Transferring of MEKC-FD to chip-CE allowed for shorter analysis time (2.5 min) and decreased sample consumption. The chip-CE-FD shows good detection and quantitation limits (< 7.5 μM) and precision (%RSD < 2.81%) and was employed to determine nicotine and cotinine in artificial urine. This work reveals the potential of CE and chip-CE with dual detectors as simultaneous, convenient and rapid methods for monitoring pyridine derivatization.
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  • Ju-Yeon MOON, Sun Ju KIM, Myeong Hee MOON, Bong Chul CHUNG, Man Ho CHO ...
    Type: Original Papers
    2013 Volume 29 Issue 3 Pages 345-351
    Published: March 10, 2013
    Released: March 10, 2013
    JOURNALS FREE ACCESS
    As a simple and rapid method for small-molecule analysis, matrix-assisted laser desorption ionization coupled with linear ion-trap tandem mass spectrometry (MALDI-LTQ-MS/MS) was used to differentially quantify 2- and 4-methoxyestrogens in spiked serum samples. Both 2- and 4-methoxyestrogens were consistently identified using distinct analyte-matrix adduct [M+H+CHCA]+ precursor ions when a mixture of 10 mg mL−1 α-cyano-4-hydroxycinnamic acid (CHCA) in 0.2% trifluoroacetic acid/70% acetonitrile was used as the MALDI matrix. Especially, unusual isomeric product ions from each precursor ion were characterized during MALDI-MS/MS analysis, which permitted differential estimations of isomeric 2- and 4-methoxylated estrone and 17β-estradiol. The calibration linearity was higher than 0.99 in the dynamic range, while the inter-day precision and accuracy ranged from 6.8 to 30.6%, and from 91.4 to 108.5%, respectively. The present technique could be used as a screening assay for 2- and 4-methoxyestrogens without the need for prior chromatographic separation, opening up possible applications in large-scale pharmacokinetic studies.
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  • Kanae ITO, Koji YOSHIDA, Kikujiro UJIMOTO, Toshio YAMAGUCHI
    Type: Original Papers
    2013 Volume 29 Issue 3 Pages 353-359
    Published: March 10, 2013
    Released: March 10, 2013
    JOURNALS FREE ACCESS
    The thermal behavior and structure of water confined in Sephadex G15 gel were investigated over a temperature range of 298 – 173 K at hydration levels, h (= mass of water/mass of dry G15 gel), of 0.24 – 1.38 by differential scanning calorimetry (DSC) and an X-ray diffraction (XRD) method, respectively. The ice-melting peaks on the DSC curves were deconvoluted to estimate the amounts of three states of water in G15 with h: free water, freezable bound water, and unfrozen water. The X-ray radial distribution functions of unfrozen water at h = 0.24 revealed that the hydrogen-bonded structure of water is largely distorted, due to hydrogen bonding with the surface hydroxyl groups of gel substrates, compared with those of freezable bound water at h = 0.47 and bulk water. A plausible separation mechanism of solutes in gel chromatography was considered from a structural point of view of confined water.
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  • Farhang MIZANI, Mojtaba SHAMSIPUR, Mohammad R. YAFTIAN, Dominique MATT
    Type: Original Papers
    2013 Volume 29 Issue 3 Pages 361-366
    Published: March 10, 2013
    Released: March 10, 2013
    JOURNALS FREE ACCESS
    A new coated ion-selective electrode for the determination of trace thorium ions by flow-injection potentiometry (FIP) has been developed. A poly(vinyl chloride) (PVC)-based membrane was coated on a graphite electrode. The optimum membrane contained 5 wt% diphosphoryl-dicarboxylicacid-p-tert-butylcalix[4]arene (L) as the ionophore, 59 wt% dioctyl phthalate (DOP), 33 wt% PVC and 3 wt% additive sodium tetraphenylborate. The response was linear from 2.0 × 10−7 to 1.0 × 10−2 M with a slope of 13.9 mV decade−1 and a limit of detection of 9.0 × 10−8 M. The pH-independent region ranged from 3.15 to 6.5, and the lifetime was longer than 8 weeks when used in the flow injection analysis (FIA) system. Selectivity coefficients for several ions were obtained by the separate solutions method. Results showed that, for all cations used, the selectivity coefficients were in the order of 10−3, or smaller. The flow cell is simple to construct and free from memory effect problems over long periods of use. The proposed sensor was successfully applied to the direct determination of thorium in both real and synthetic samples.
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Notes
  • Toyohiro NAITO, Ai YATSUHASHI, Noritada KAJI, Taeko ANDO, Kazuo SATO, ...
    Type: Notes
    2013 Volume 29 Issue 3 Pages 367-371
    Published: March 10, 2013
    Released: March 10, 2013
    JOURNALS FREE ACCESS
    A microchip-based real-time polymerase chain reaction (PCR) device has been developed for the genetic tug-of-war (gTOW) method that provides quantitative data for research on biorobustness and systems biology. The device was constructed of a silicon glass chip, a temperature controlling Peltier element, and a microscope. A parallel real-time amplification process of target genes on the plasmids and the housekeeping genes in a model eukaryote Saccharomyces cerevisiae were detected simultaneously, and the copy number of the target genes were estimated. The device provides unique quantitative data that can be used to augment understanding of the system-level properties of living cells.
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  • Saaya MINEMATSU, Xing-Zheng WU
    Type: Notes
    2013 Volume 29 Issue 3 Pages 373-375
    Published: March 10, 2013
    Released: March 10, 2013
    JOURNALS FREE ACCESS
    Capillary electrophoresis (CE) is usually off-line combined with an adsorption/desorption method to analyze gaseous or atmospheric samples. Here, we demonstrated direct sampling in the air of CE. The inlet end of a fused silica capillary filled with a pH 7.2 phosphate buffer was placed in the air for absorbing gaseous or volatile components, while the outlet end was immersed into a buffer vial at the low electric potential side. After a certain period of time, the inlet end was immersed into another buffer vial at the high electric potential side; CE was carried out by applying a high electric voltage of 20 kV. An UV-absorbance detector (wavelength, 254 nm) was used in CE. Evaporated vanillin in air was used as model gaseous sample. Experimental factors, such as a height difference between the inlet end and the outlet buffer, were investigated in detail. Fast detection of evaporated vanillin in indoor air was demonstrated.
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  • Seiko NAKAGAWA
    Type: Notes
    2013 Volume 29 Issue 3 Pages 377-380
    Published: March 10, 2013
    Released: March 10, 2013
    JOURNALS FREE ACCESS
    The reaction of the hydroxy radical with thymidine and poly-hydroxy benzenes; i.e., catechol, resorcinol, hydroquinone, and pyrogallol, was studied by ESR spin trapping combined with the UV-A photolysis of hydrogen peroxide. The obtained relative reaction rates reasonably agreed with those previously obtained by pulse radiolysis. Electron distribution in the HOMO obtained by DFT calculations also supports the resulting order of reactivity of the polyphenols.
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