Analytical Sciences
Online ISSN : 1348-2246
Print ISSN : 0910-6340
ISSN-L : 0910-6340
Volume 23 , Issue 5
Showing 1-21 articles out of 21 articles from the selected issue
Original Papers
  • Masahiro NARUKAWA, Yutaka MATSUMI, Jun MATSUMOTO, Kenshi TAKAHASHI, Ak ...
    2007 Volume 23 Issue 5 Pages 507-512
    Published: 2007
    Released: May 10, 2007
    JOURNALS FREE ACCESS
    A real-time analysis of secondary organic aerosol (SOA) particles formed from cyclohexene ozonolysis in a smog chamber was performed using a laser-ionization single-particle aerosol mass spectrometer (LISPA-MS). The instrument obtains both size and chemical compositions of individual aerosol particles with a high time-resolution (∼2 s at the maximum). Both positive and negative-ion mass spectra are obtained. Standard particles generated from dicarboxylic acid solutions using an atomizer were also analyzed. For both standard and SOA particles, the negative-ion mass spectra provided information about the molecular weights of the organic compounds in the particles, since the intense ions in the negative-ion mass spectra are mainly attributable to the molecular-related ions [M-H]-. It was demonstrated that the real-time single-particle analysis of SOA particles by the LISPA-MS technique can reveal the formation and transformation processes of SOA particle in smog chambers.
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  • Hideki MATSUBARA, Hajime OHTANI
    2007 Volume 23 Issue 5 Pages 513-516
    Published: 2007
    Released: May 10, 2007
    JOURNALS FREE ACCESS
    The double-bond conversion of UV-cured resins prepared from pentaerithritol triacylate (PETA) was determined by pyrolysis-gas chromatography in the presence of an organic alkali, tetramethylammonium hydoxide (TMAH). The pyrogram of the uncured prepolymer compound, consisting of PETA and a photoinitiator, 2,2-dimethoxy-2-phenylacetophenone, contained specific products reflecting the original acrylate structure, such as methyl acrylate (MA) and methyl ethers of pentaerithritol. Meanwhile, in pyrograms of the UV-cured PETA, the yields of MA considerably decreased. The double-bond conversions of the cured resins, irradiated with various UV dosages, were calculated based on the relative yields of MA among specific products in the pyrograms. The conversions determined by this approach were analyzed by comparing them with those estimated by Fourier-transform infrared spectroscopy.
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  • Takashi KATSU, Tomonori IMAMURA, Keiko KOMAGOE, Kazufumi MASUDA, Tohru ...
    2007 Volume 23 Issue 5 Pages 517-522
    Published: 2007
    Released: May 10, 2007
    JOURNALS FREE ACCESS
    The changes induced by biologically active substances in the permeability to K+ and calcein of liposomes composed of egg phosphatidylcholine and cholesterol were measured simultaneously in order to rapidly screen the sizes of pores formed in a membrane, using different sized markers. The substances examined in the present study were classified into three types based on differences in the rates at which K+ and calcein were released. The first type released only K+, and included gramicidin A. The second type predominantly released K+, preceding the release of calcein, and included amphotericin B and nystatin. The third type, including antimicrobial peptides, such as gramicidin S, alamethicin, and melittin, and several membrane-active drugs, like celecoxib (non-steroidal anti-inflammatory drug), 1-dodecylazacycloheptan-2-one (named azone; skin permeation enhancer), and chlorpromazine (tranquilizer), caused the release of K+ and calcein simultaneously. Thus, the sizes of pores formed in a liposomal membrane increased in the following order: types one, two, and three. We determined the size more precisely by conducting an osmotic protection experiment, measuring the release of calcein in the presence of osmotic protectants of different sizes. The radii of pores formed by the second type, amphotericin B and nystatin, were 0.36 - 0.46 nm, while the radii of pores formed by the third type were much larger, 0.63 - 0.67 nm or more. The permeability changes induced by substances of the third type are discussed in connection with a transient pore formed in a lipid packing mismatch taking place during the phase transition of dipalmitoylphosphatidylcholine liposomes.
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  • Shuuji HARA, Noriaki SASAKI, Daizi TAKASE, Shouichi SHIOTSUKA, Kentaro ...
    2007 Volume 23 Issue 5 Pages 523-526
    Published: 2007
    Released: May 10, 2007
    JOURNALS FREE ACCESS
    A rapid and sensitive HPLC method for the simultaneous determination of paraquat and diquat in human serum has been developed. After deproteinization of the serum with 10% trichloroacetic acid, the samples were separated on a reversed-phase column, and subsequently reduced to their radicals with alkaline sodium hydrosulfite solution. These radicals were monitored with a UV detector at 391 nm. This method permitted the reliable quantification of paraquat over linear ranges of 50 ng - 10 µg/ml and 100 ng - 10 µg/ml for diquat in human serum. The within- and between-day variations are lower than 2.3 and 2.2%, respectively. This technique was also utilized to determine the paraquat and diquat serum levels in a patient who had ingested herbicide (Prigrox L®) containing paraquat and diquat.
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  • Asadollah BEIRAGHI, Ali Reza ZAREI, Saeed BABAEE
    2007 Volume 23 Issue 5 Pages 527-531
    Published: 2007
    Released: May 10, 2007
    JOURNALS FREE ACCESS
    A cloud-point extraction process using a mixed micelle of the cationic surfactant cetyl pyridinium chloride (CPC) and non-ionic surfactant Triton X-114 to extract beryllium from aqueous solutions was investigated. The method is based on the color reaction of beryllium with Chrome Azurol S (CAS) in acetate buffer and the mixed micelle-mediated extraction of the complex. This complex was concentrated in a surfactant-rich phase after separation. The optimal extraction and reaction conditions (e.g. pH, reagent and surfactant concentrations, temperature, incubation and centrifuge times) were evaluated and optimized. Under the optimized conditions, the analytical characteristics of the method (e.g. limit of detection, linear range and preconcentration factor) were obtained. Linearity was obeyed in the range of 0.30 - 18 ng mL-1 of beryllium and the detection limit of the method was 0.05 ng mL-1. The interference effect of some cations and anions was also studied. The proposed method was successfully applied to the determination of beryllium in real water samples.
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  • Yun Fu OU-YANG, Yong Sheng WANG, Xian Wen MI, Jin Hua XUE, Ying WANG
    2007 Volume 23 Issue 5 Pages 533-537
    Published: 2007
    Released: May 10, 2007
    JOURNALS FREE ACCESS
    A novel method for the rapid and sensitive analysis of 1-hydroxypyrene (1-OHP) in human urine has been developed that uses a resonance light scattering (RLS) technique. The assay was based on the interaction of ethyl violet (EV) with 1-hydroxypyrene to form an ion-associate complex, which resulted in the enhancement of RLS intensity and the appearance of new RLS spectra. In the presence of anionic surfactant, the maximum RLS peak of the system was located at 396 nm at pH 8.0. Under the optimum conditions, it was found that the enhanced RLS intensity was directly proportional to the concentration of 1-hydroxypyrene in the range of 4.0 - 982 µg l-1. The detection limit was 1.2 µg l-1 and the recoveries of 1-hydroxypyrene were 92.8 - 102.3% (n = 6). The proposed method was successfully applied to the analysis of human urine samples. The results of 1-hydroxypyrene were in agreement with those obtained by the method of high-performance liquid chromatography.
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  • Xingxiang WANG, Qingman LI, Jianhua DING, Mingbiao LUO, Taolin ZHANG, ...
    2007 Volume 23 Issue 5 Pages 539-543
    Published: 2007
    Released: May 10, 2007
    JOURNALS FREE ACCESS
    Due to specific adsorption to variable charge soils, low molecular weight organic acids (LMWOAs) have not been sufficiently extracted, even if common extractants, such as water and 0.1 M sodium hydroxide (NaOH), were employed. In this work, the method for extracting LMWOAs in soils with 0.1 M NaOH was improved for variable charge soils; e.g. 1.0 M potassium fluoride (KF) with pH 4.0 was applied as an extractant jointed with 0.1 M NaOH based on its stronger ability to change the electrochemical properties of variable charge soils by specific adsorption. With the proposed method, the recoveries of oxalic, tartaric, malic, citric and fumaric acids were increased from 83 ± 4, 93 ± 1, 22 ± 2, 63 ± 5 and 84 ± 3% to 98 ± 2, 100 ± 2, 85 ± 2, 90 ± 2 and 89 ± 2%, respectively, compared with NaOH alone. Simultaneously, the LMWOAs in Agri-Udic Ferrosol with field moisture were measured with a satisfactory result.
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  • Min-Kyu HAN, Moon-Hyeong SEO, Dohoon LEE, Seung Hyun KIM, Hae-Sim PARK ...
    2007 Volume 23 Issue 5 Pages 545-549
    Published: 2007
    Released: May 10, 2007
    JOURNALS FREE ACCESS
    A sensitive and multiplexed assay of allergen-specific human immunoglobulin E (IgE) is of great significance in the precise diagnosis of allergies. We report on the optimization of critical factors for chip-based analysis of IgE in human serum with a high reliability. Extracts of two mite species were used as model allergens, and were spotted onto a glass slide for the construction of an allergen chip. Respective allergen-specific IgE in human serum was analyzed by using biotinylated anti-human IgE and a streptavidin-Cy3 conjugate. Factors affecting the performance of the allergen chip were investigated and optimized. Especially, the effect of additives, the concentrations of biotinylated anti-human IgE and the streptavidin-Cy3 conjugate, the serum dilution factor, and the concentration of allergen extract as a capturing agent were examined in detail. Under the optimized conditions, a chip-based analysis for sera from 43 patients revealed a reliable and reproducible diagnosis of respective allergies, showing a good correlation with a conventional CAP assay.
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  • Hong-Yuan LUO, Xiao-Bing ZHANG, Jian-Hui JIANG, Chun-Yan LI, Jing PENG ...
    2007 Volume 23 Issue 5 Pages 551-555
    Published: 2007
    Released: May 10, 2007
    JOURNALS FREE ACCESS
    A porphyrin derivative (fluorophore) appended with bipyridine (ionophore) has been applied for preparation of a Cu2+-sensitive optical chemical sensor, which is based on fluorescence quenching of porphyrin derivative entrapped in a poly(vinyl chloride) membrane by the energy transfer process. The sensor exhibits a linear response toward Cu2+ in the concentration range 2.0 × 10-8 - 1.0 × 10-5 M, with a working pH range from 6.0 to 8.0 and a high selectivity. The detection limit is 5 × 10-9 M. The response time for Cu2+ is less than 5 min with concentrations lower than 5 × 10-6 M. The optode can be regenerated using 0.3 M EDTA (pH 9) and acetate buffer solution. The effect of the composition of the sensor membrane was studied, and the experimental conditions were optimized. The sensor has been used for direct determination of Cu2+ in water samples with satisfied results.
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  • Qian PENG, Xiaoxia GE, Chongqiu JIANG
    2007 Volume 23 Issue 5 Pages 557-561
    Published: 2007
    Released: May 10, 2007
    JOURNALS FREE ACCESS
    A new spectrofluorometric method has been developed for the determination of trace amounts of coenzyme A (CoA). Using europium (Eu3+)-tetracycline (TC) complex as a fluorescent probe in the buffer solution of pH 6.80, CoA could remarkably enhance the fluorescence intensity of the Eu3+-TC complex at λ = 612 nm after adding H5IO6 and the enhanced fluorescence intensity is in proportion to the concentration of CoA. Optimum conditions for the determination of CoA were also investigated. The dynamic range for the determination of CoA is 6.08 × 10-8 - 1.84 × 10-5 mol L-1 with detection limit of 4.62 × 10-8 mol L-1. This method is simple, practical and relatively free of interference from coexisting substances and can be successfully applied to determination of CoA in injection, human serum and pig liver samples. Moreover, the enhancement mechanisms of the fluorescence intensity in the Eu3+-TC system and the CoA-Eu3+-TC system have been also discussed.
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  • M. R. NATEGHI, M. H. FALLAHIAN
    2007 Volume 23 Issue 5 Pages 563-567
    Published: 2007
    Released: May 10, 2007
    JOURNALS FREE ACCESS
    Electropolymerization of anthranilic acid/pyrrole (AA/PY) at solid substrate electrodes (platinum, gold, and glassy carbon) gave stable and water-insoluble films under a wide range of pH. Combining high conductivity of the polypyrrole (PPY) and pH independence of the electrochemical activity of the self-doped carboxylic acid-substituted polyaniline allows us to prepare an improved functionalized PPY-modified electrode to collect and measure Cu(I) species. The differential pulse stripping analysis of the copper ions using a polyanthranilic acid-co-polypyrrole (PAA/PPY)-modified electrode consisted of three steps: accumulation, electrochemical reduction to the elemental copper and stripping step. Factors affecting these steps, including electropolymerization conditions, accumulation and stripping medium, reduction potential, reduction time and accumulation time, were systematically investigated. A detection limit of 5.3 × 10-9 M Cu(I) was achieved for a 7.0 min accumulation. For 12 determinations of Cu(I) at concentrations of 1.0 × 10-8 M, an RSD of 3.5% was obtained. The log Ip was found to vary linearly with log[CuI] in the concentration range from 7.0 × 10-9 to 1.0 × 10-5 M.
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  • Zhou-Sheng YANG, Jun ZHAO, Da-Peng ZHANG, Yun-Chun LIU
    2007 Volume 23 Issue 5 Pages 569-572
    Published: 2007
    Released: May 10, 2007
    JOURNALS FREE ACCESS
    A highly sensitive electrochemical biosensor for the detection of trace amounts of promethazine has been designed. Double stranded (ds)DNA molecules are immobilized onto a pretreated glassy carbon electrode (GCE(ox)) surface. The voltammetric behaviors of promethazine on DNA-modified electrode were explored by means of cyclic voltammetry (CV) and differential pulse voltammetry (DPV). The promethazine gave rise to a pair of well-defined peaks, which appeared at Epc = 52 mV and Epa = 96 mV (vs. Ag/AgCl) in 0.10 M acetate buffer (pH 5.0). The peak current was linearly enhanced with increasing the concentration of promethazine. The calibration was linear for promethazine over the range of 4.7 × 10-10 to 9.3 × 10-9 M with a correlation coefficient of 0.999. The limit of detection (LODs) was 3.0 × 10-10 M (S/N = 3). The modified electrode was applied to determine promethazine in human blood samples with satisfactory results.
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  • Hosny IBRAHIM, Amal KHORSHID
    2007 Volume 23 Issue 5 Pages 573-579
    Published: 2007
    Released: May 10, 2007
    JOURNALS FREE ACCESS
    A comparative study was made between developed chemically modified carbon paste electrodes and PVC membrane electrodes for the cationic surfactant cetyltrimethylammonium bromide (CTAB). The carbon paste electrode modified with cetyltrimethylammonium-tetrachloropalladate(II) (CTA-TClP) provides a more sensitive and stable device than that shown by electrodes with an inner reference solution. The best performance was obtained by an electrode based on the paste containing 3.6 wt% CTA-TCIP, 1.8 wt% ethylhexadecyldimethylammonium bromide, 37.6 wt% graphite and 57 wt% tricresyl phosphate. The sensor exhibited a Nernstian response for CTAB over a wide concentration range of 3.5 × 10-7 to 1.0 × 10-3 M with a detection limit of 2.0 × 10-7 M between pH 2.7 and 8.2 with a fast response time of ≤15 s. The electrode showed excellent selectivity for CTAB over a large number of ions. Interferences caused by common cationic surfactants have been investigated in simulated mixtures containing high concentration levels of interfering surfactants, and the sensor was found to be tolerant against these compounds.
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  • Tai-Ming ZHANG, Bin YUAN, Yi-Zeng LIANG, Juan CAO, Chun-Xiao PAN, Bin ...
    2007 Volume 23 Issue 5 Pages 581-587
    Published: 2007
    Released: May 10, 2007
    JOURNALS FREE ACCESS
    In order to deal with the matrix effect in the simultaneous determination of multi-components in a complex system, we have developed a novel method named matrix coefficient multivariate calibration method (MCMCM) for simultaneously determining n analytes in complex systems. The calibration models of n analytes, which are based on the experimental data of known samples, are first transformed into n linear equations, and then the equations are solved to obtain matrix calibration coefficients of the analytes in congeneric samples. In this way, the concentrations of n analytes in the unknown sample could be obtained easily and simultaneously by solving another n-variate linear equations with the help of the matrix calibration coefficients obtained-above. The method proposed in this work has been tested by voltammetry and atomic absorption spectrometry (AAS) with satisfactory results. On determining the elements such as Cu, Pb, Cd, Ni, Zn, Fe, Mn, Co, Ca, Mg, etc. in synthetic samples, the relative standard deviations (RSDs) of the results were 0.91 - 4.5%, and the recoveries were 95.8 - 105%. For actual samples, the RSDs and the recoveries were 1.5 - 6.9 and 92.0 - 110%, respectively.
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