Analytical Sciences
Online ISSN : 1348-2246
Print ISSN : 0910-6340
ISSN-L : 0910-6340
Volume 28 , Issue 12
Showing 1-19 articles out of 19 articles from the selected issue
Rapid Communications
Original Papers
  • Nobuo UEHARA, Osamu YOSHIDA
    Type: Original Papers
    2012 Volume 28 Issue 12 Pages 1125-1132
    Published: December 10, 2012
    Released: December 10, 2012
    JOURNALS FREE ACCESS
    Thermoresponsive gold nanocomposites encapsulating Nile red were fabricated by the conjugation of gold nanoparticles containing Nile red with a thermoresponsive polymer, poly(N-isopropylacrylamide(90 mol%)-co-N-acryloyldiethylenetriamine(10 mol%)). They were then examined as a model of drug delivery carriers and colloidal fluorescence sensors. Nile red, as a fluorophore to be released, was introduced to the surface of gold nanoparticles prior to conjugation with thermoresponsive polymers. Heating a solution at 90°C resulted in shrinkage of the thermoresponsive polymers, which facilitated disassembly of the gold nanocomposites in the presence of glutathione. This disassembly caused a replacement of Nile red with glutathione at the surface of the gold nanoparticles, followed by the release of Nile red from the gold nanocomposites. Nile red liberated from the gold surface recovered its inherent fluorescence properties that had been quenched by gold nanoparticles through fluorescence resonance energy transfer. The fluorescence intensity of the liberated Nile red increased linearly as the glutathione concentration increased up to 1.0 × 10−5 mol/L, demonstrating that thermoresponsive gold nanocomposites can be used as colloidal sensors or drug delivery carriers that can be manipulated by the concentration of glutathione and the solution temperature. The applicability of the thermoresponsive gold nanocomposites to colloidal fluorescence probes was also checked by assay of glutathione in tablets.
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  • Yoshito NAKASHIMA, Tsukasa NAKANO
    Type: Original Papers
    2012 Volume 28 Issue 12 Pages 1133-1138
    Published: December 10, 2012
    Released: December 10, 2012
    JOURNALS FREE ACCESS
    X-ray computed tomography (CT) images obtained with a polychromatic X-ray source were simulated by computer for homogeneous solutions and suspensions containing a heavy element. When the K-edge of the element was near the peak energy of the polychromatic X-ray spectrum, the degree of beam hardening in the simulated CT image strongly depended on the atomic number and molar concentration of the heavy element. We analyzed the beam hardening of a single measured CT image of a CeCl3 aqueous solution sample, and successfully estimated the atomic number and the molar concentration of Ce simultaneously within a certain error. This single-shot, or single-energy (as opposed to dual-energy), CT method permits quick, nondestructive screening of a hazardous heavy element in a solution or suspension confined in a container.
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  • Kentaro TOMITA, Toshio ISHIOKA, Akira HARATA
    Type: Original Papers
    2012 Volume 28 Issue 12 Pages 1139-1144
    Published: December 10, 2012
    Released: December 10, 2012
    JOURNALS FREE ACCESS
    Anion-selective detection is demonstrated for sulfate ion in aqueous solutions by using two-photon excited fluorescence of gold nanoparticles (AuNPs) modified with a thiourea-based anion receptor, bis[2-(3-(4-nitrophenyl)thioureido)ethyl]disulfide. The fluorescent intensity increased with the change of the sulfate concentration in the solution from 10−4 to 10−3 M. In comparison with an unadsorbed receptor molecule in bulk acetonitrile solution, the molecule on AuNPs in water showed improved affinity for sulfate ion. The controllability of the hydrophobicity around receptor molecules on AuNPs is considered a dominant contributing factor for improved sulfate affinity. This unique feature of the surface enables us to detect anionic species in an aqueous phase where a dye-type indicator has poor sensitivity.
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  • Yoshihide TATSUNO, Takumi KOZURU, Yumi YOSHIDA, Kohji MAEDA
    Type: Original Papers
    2012 Volume 28 Issue 12 Pages 1145-1151
    Published: December 10, 2012
    Released: December 10, 2012
    JOURNALS FREE ACCESS
    Two liquid membrane oscillators composed of aqueous solutions containing cetyltrimethylammonium chloride (CTACl) and alcohol, W1 and W1′, a nitrobenzene solution containing picric acid, O, and pure water phase, W2, were connected through O and W2 as common phases. Two glass tubes including W1 and W1′ were inserted into the O/W2 interface. Both membrane potential differences between W1 and W2 and that between W1′ and W2 were recorded using a pair of Ag/AgCl electrodes located near the orifice of each tube. The oscillations of two membrane potentials synchronized each other when the distance between the tubes was less than 10 mm. The synchronization was attended by the propagation of a potential pulse from one side to another with an interval of approximately 70 ms at a distance of 10 mm. It was examined whether the propagation of the potential pulse was due to electric conduction in bulk phases, or due to the interfacial conduction by several experiments in the addition of indifferent electrolytes or nonionic surfactant. Consequently, it has been demonstrated that the propagation of oscillation pulse was dominated mainly by the interfacial conduction process, and additionally by the bulk ionic conduction and that the interfacial diffusion and distribution of Cl played a crucial role.
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  • Hajime KATANO, Takuma YONEOKA, Naoko KITO, Chitose MARUYAMA, Yoshimits ...
    Type: Original Papers
    2012 Volume 28 Issue 12 Pages 1153-1157
    Published: December 10, 2012
    Released: December 10, 2012
    JOURNALS FREE ACCESS
    A biopolymer ε-poly-L-lysine (εPL) exists as a fully protonated form (εPLHn+) in solutions at pH < 4. Around pH 3.5, at which the tetraphenylborate (TPB) anion is not decomposed immediately, the εPLHn+ cation associates with the TPB anion to form a precipitate of 1:n stoichiometry, εPLH(TPB)n. By the addition of NaTPB to a culture broth containing εPL and NH4+ and K+ ions, not only the polycationic εPLHn+ but also the monovalent cations would be precipitated with the TPB anion. However, εPLH(TPB)n was purified by washing the mixed precipitate with acetone, in which NH4TPB and KTPB are soluble. By mixing the εPLH(TPB)n precipitate and a high-concentration HCl solution, the TPB anion was decomposed immediately to hydrophobic molecules. By the addition of a much larger volume of acetone to the reaction mixture, the decomposition products dissolved in the solvent. Simultaneously, εPL was precipitated as the hydrochloride salt. Thus, εPL has been separated and purified from the culture broth. Also, the method has been successfully applied to the separation of oligomeric εPL species. The present chemical separation method is rapid, simple, and easy to carry out, and can be utilized in bioengineering studies of such basic peptides or polyamines.
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  • Yuta MIYAMAE, Yumika YAMAKAWA, Marie KAWABATA, Yukihiro OZAKI
    Type: Original Papers
    2012 Volume 28 Issue 12 Pages 1159-1164
    Published: December 10, 2012
    Released: December 10, 2012
    JOURNALS FREE ACCESS
    The phenomenon of skin aging may be categorized broadly into photoaging caused by exogenous factors and physiological aging induced by endogenous factors. A near-infrared diffuse reflectance (NIR-DR) spectroscopy method was recently proposed for non-invasive evaluation of changes that occur within the skin of hairless mice that were divided into an ultraviolet-B (UVB)-irradiated group (photoaging) and a non-irradiated group (physiological aging). In the present study, a non-invasive method to assess changes in human skin was developed and tested. For investigation of photoaging and physiological aging, NIR-DR spectra in the 8000 to 4000 cm−1 region were measured from the outer forearm (sun-exposed) and the inner upper arm (sun-protected) of 86 females ranging in age from 23 to 69 years. The obtained spectra were subjected to principal component analysis (PCA). PCA results suggested that contributions of both types of aging occurring within the skin can be monitored and quantitatively assessed using the 5990 to 5490 and 5000 to 4480 cm−1 regions of second derivative NIR-DR spectra, respectively. This study demonstrates that for human skin, NIR-DR spectroscopy and PCA may allow non-invasive assessment of the degree of photoaging and physiological aging due to degenerative changes in protein elasticity and reduction in protein quantity, respectively.
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  • Takashi NISHII, Takuma GENKAWA, Masahiro WATARI, Yukihiro OZAKI
    Type: Original Papers
    2012 Volume 28 Issue 12 Pages 1165-1170
    Published: December 10, 2012
    Released: December 10, 2012
    JOURNALS FREE ACCESS
    A new selection procedure of an informative near-infrared (NIR) region for regression model building is proposed that uses an online NIR/mid-infrared (mid-IR) dual-region spectrometer in conjunction with two-dimensional (2D) NIR/mid-IR heterospectral correlation spectroscopy. In this procedure, both NIR and mid-IR spectra of a liquid sample are acquired sequentially during a reaction process using the NIR/mid-IR dual-region spectrometer; the 2D NIR/mid-IR heterospectral correlation spectrum is subsequently calculated from the obtained spectral data set. From the calculated 2D spectrum, a NIR region is selected that includes bands of high positive correlation intensity with mid-IR bands assigned to the analyte, and used for the construction of a regression model. To evaluate the performance of this procedure, a partial least-squares (PLS) regression model of the ethanol concentration in a fermentation process was constructed. During fermentation, NIR/mid-IR spectra in the 10000 – 1200 cm−1 region were acquired every 3 min, and a 2D NIR/mid-IR heterospectral correlation spectrum was calculated to investigate the correlation intensity between the NIR and mid-IR bands. NIR regions that include bands at 4343, 4416, 5778, 5904, and 5955 cm−1, which result from the combinations and overtones of the C–H group of ethanol, were selected for use in the PLS regression models, by taking the correlation intensity of a mid-IR band at 2985 cm−1 arising from the CH3 asymmetric stretching vibration mode of ethanol as a reference. The predicted results indicate that the ethanol concentrations calculated from the PLS regression models fit well to those obtained by high-performance liquid chromatography. Thus, it can be concluded that the selection procedure using the NIR/mid-IR dual-region spectrometer combined with 2D NIR/mid-IR heterospectral correlation spectroscopy is a powerful method for the construction of a reliable regression model.
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  • Shin-ichi MIYASHITA, Kazumi INAGAKI, Tomohiro NARUKAWA, Yanbei ZHU, Ta ...
    Type: Original Papers
    2012 Volume 28 Issue 12 Pages 1171-1177
    Published: December 10, 2012
    Released: December 10, 2012
    JOURNALS FREE ACCESS
    A certified reference material (CRM) for trace cadmium and other elements in brown rice flour was developed at the National Metrology Institute of Japan (NMIJ). The CRM was provided as a dry powder after drying and frozen pulverization of fresh brown rice obtained from a Japanese domestic market. Characterization of the property value for each element was carried out exclusively by NMIJ with at least two independent analytical methods, including inductively coupled plasma mass spectrometry (ICP-MS), ICP high-resolution mass spectrometry, isotope-dilution ICP-MS, ICP optical emission spectrometry, and graphite-furnace atomic-absorption spectrometry. Property values were provided for six elements (Mn, Fe, Cu, Zn, As, and Cd). The concentration range of the property values was from 0.280 mg kg−1 of As to 31.8 mg kg−1 of Zn. The combined relative standard uncertainties of the property values were estimated by considering the uncertainties of the homogeneity, characterization, difference among analytical methods, dry-mass correction factor, and calibration standard. The range of the relative combined standard uncertainties was from 1.1% of Zn to 1.6% of As.
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  • Jun WATANABE, Jun TAKEBAYASHI, Yuko Takano-ISHIKAWA, Akemi YASUI
    Type: Original Papers
    2012 Volume 28 Issue 12 Pages 1179-1182
    Published: December 10, 2012
    Released: December 10, 2012
    JOURNALS FREE ACCESS
    Official Methods of Analysis of AOAC International (OMA) 2006.07 was originally designed for quantifying flavonol aglycones in ginkgo dietary supplements. To determine whether the method is applicable to the quantification of flavonol aglycones in lyophilized onion samples, single- and multi-laboratory validation studies were performed. Triplicated measurements on 3 different days revealed that the mean quercetin content was 3.48 g/kg dry weight, and the relative repeatability standard deviation (RSDr) and the relative intermediate standard deviation (RSDint) were 0.8 and 1.8%, respectively. The recovery of quercetin-3-O-glucoside spiked at 3 different amounts (1.56, 3.12, and 6.24 g/kg dry weight of onion) ranged from 98.42 to 100.31%, and the RSDr and RSDint ranged from 2.2 to 5.9%, and from 3.4 to 5.2%, respectively. A multi-laboratory validation study showed that the mean quercetin contents were 2.80 and 6.61 g/kg dry weight, and that satisfactory inter-laboratory precision (RSDr and RSDR ranged from 0.41 to 0.92%, and from 6.73 to 7.62%, respectively); all HorRat values were less than 2. These results indicate that OMA 2006.07 is applicable to the determination of the quercetin content of lyophilized onion samples.
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  • Kiwao KADOKAMI, Shuangye PAN, Duong Thi HANH, Xuehua LI, Terumi MIYAZA ...
    Type: Original Papers
    2012 Volume 28 Issue 12 Pages 1183-1189
    Published: December 10, 2012
    Released: December 10, 2012
    JOURNALS FREE ACCESS
    A comprehensive analytical method for nearly 1000 semi-volatile organic compounds (SVOC) in sediments has been developed using an automated identification and quantification system with a GC-MS database. The results of recovery tests using model compounds, which comprise of 119 non-polar to polar compounds, showed that the method can quantitatively analyze most SVOC, except for very polar substances. Analytical results of a standard reference material were close to certified concentrations. The detection limits of the method were 4 μg/kg when measuring by TIM and 0.4 μg/kg by SIM. The method was applied to actual sediments in rivers in Ho Chi Minh City, Vietnam. A large number of substances, including persistent organic pollutants, which seem to be discharged from domestic sources, were found at relatively high concentrations. From these results, it is confirmed that the developed method is a useful way to obtain a holistic picture of pollution by SVOC, and is a good tool for rapid screening of chemical pollution in sediments.
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  • Netnapit KAEWCHUAY, Keiichi FUKUSHI, Ai TSUBOI, Hideo OKAMURA, Keiitsu ...
    Type: Original Papers
    2012 Volume 28 Issue 12 Pages 1191-1196
    Published: December 10, 2012
    Released: December 10, 2012
    JOURNALS FREE ACCESS
    We proposed a capillary zone electrophoresis (CZE) procedure using field-amplified sample injection (FASI) for the simultaneous determination of pyridine-triphenylborane (PTPB) and its degradation products: diphenylborinic acid (DPB), phenylboronic acid (MPB), and phenol. The LODs for PTPB, DPB, MPB, and phenol were, respectively, 0.85, 0.88, 44, and 28 μg L−1. The RSDs (n = 4) for the analytes listed above were in respective ranges of 6.2 – 14, 5.9 – 10, and 0.49 – 0.62% for the peak area, peak height, and migration time. The compounds were extracted from paint-waste samples collected from shipyards using a siliga-gel column. The extract was dissolved with acetonitrile containing 1% (v/v) pyridine. The samples were then analyzed using CZE, revealing respective concentrations of 0.076 – 0.53, 0.015 – 0.36, 1.7 – 22, and 1.2 – 13 μg g−1. The proposed FASI-CZE method is a simple and promising procedure that is expected to be useful for the determination of PTPB and its degradation products in paint wastes.
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  • Miran LEE, Jeonghyeon PARK, Mi-sun LIM, Sook Jin SEONG, Joomi LEE, Jeo ...
    Type: Original Papers
    2012 Volume 28 Issue 12 Pages 1197-1201
    Published: December 10, 2012
    Released: December 10, 2012
    JOURNALS FREE ACCESS
    Bo-yang-hwan-o-tang (BHT) is an oriental herbal medicine for treating brain disorders such as cerebral ischemia. The objective of this study was to develop an economically feasible and time-saving high-throughput screening method to monitor the potential inhibitory effects of BHT on human cytochrome P450 (CYP) enzymes in vitro. Two cocktail sets were used for incubation of human liver microsomes: Cocktail A: 6 probe substrates for CYP1A2, CYP2A6, CYP2C8, CYP2C19, CYP2D6, CYP3A4; Cocktail B: 3 for CYP2B6, CYP2C9, CYP2E1. The concentrations of the substrate metabolites were simultaneously analyzed using UPLC/MS/MS. The BHT extract had almost negligible inhibitory effects on the nine human CYP isoforms tested, with the half-maximal inhibitory concentration value ranged from 3624.99 to 45412.44 μg/ml. The results suggest that BHT extract has no inhibitory effects on CYP isoforms within the clinically recommended dosage range. We conclude that BHT might be free of drug-herb interactions when co-administered with other medicines. However, more in vivo human studies are needed to confirm these results. The high-throughput screening method can be a useful tool for drug discovery and for understanding drug interactions.
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  • Huiwen HE, Fei YAN
    Type: Original Papers
    2012 Volume 28 Issue 12 Pages 1203-1205
    Published: December 10, 2012
    Released: December 10, 2012
    JOURNALS FREE ACCESS
    A sensitive and rapid high-performance liquid chromatographic–tandem mass spectrometric (HPLC-MS/MS) method was developed for the quantitation of the major metabolite of aconitine, 16-O-demethylaconitine, lappaconitine as the internal standard in rat urine. Urine samples were precipitated with acetonitrile/methanol (3:1, v/v). Chromatographic separation was achieved on a Kromasil C18 analytical column. Detection was performed by a selective reaction monitoring (SRM) mode via an electrospray ionization (ESI) source operating in the positive ionization mode. The analytical method was validated in terms of specificity, precision, accuracy, extraction recovery. The intra- and inter-day precisions were less than 11.7%, and the accuracy was less than 14.0% for the analyte. The validated method has been applied to a pharmacokinetic study of 16-O-demethylaconitine in rats, following oral administration of aconitine.
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  • Su Jung KIM, Nayoung KIM, Eun Hee KOH, Hyun Ju YOO
    Type: Original Papers
    2012 Volume 28 Issue 12 Pages 1207-1212
    Published: December 10, 2012
    Released: December 10, 2012
    JOURNALS FREE ACCESS
    A neutral loss scan of 141, corresponding to a phosphoethanolamine head group, has been commonly used for the determination of various glycerophosphoethanolamine species in complex lipid mixtures. However, the neutral loss of 141 Da is not a major fragmentation pathway in the collision-induced dissociation (CID) of ethanolamine plasmalogens in the positive-ion mode. Thus, the use of the neutral loss scan of 141 can be problematic to observe all possible ethanolamine phospholipids in biological samples. Ethanolamine plasmalogens could easily form adducts with Ag(I) ions, and the CID of Ag(I)-adducted ethanolamine plasmalogens provided abundant head group loss of 141 with higher collision energy. Thus, all ethanolamine plasmalogens could be identified from a neutral loss scan of 141 after Ag(I) adduction. This novel approach could be a useful diagnostic tool to observe most of the possible glycerophosphoethanolamine species in complex lipid mixtures.
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  • Guilherme Dias RODRIGUES, Leandro Rodrigues de LEMOS, Luis Henrique Me ...
    Type: Original Papers
    2012 Volume 28 Issue 12 Pages 1213-1218
    Published: December 10, 2012
    Released: December 10, 2012
    JOURNALS FREE ACCESS
    An environmentally safe procedure has been developed for the extraction, separation and determination of metal ions using a monosegmented flow analysis technique that exploits an aqueous two-phase system (ATPS-MSFA). The ATPS-MSFA method was applied for the determination of cobalt, based on the reaction between Co(II) and KSCN, which produces a metallic complex that spontaneously partitions to the top phase of the ATPS composed of poly(ethylene oxide), ammonium sulfate and water. The linear range was 5.00 to 500 μmol kg−1 (R = 0.9998; n = 13) with a coefficient of variation equal to 1.14% (n = 7). The method yielded a limit of detection and a limit of quantification of 2.17 and 7.24 μmol kg−1, respectively. The ATPS-MSFA method was applied to the determination of cobalt in a nickel-cadmium battery sample and the results were validity with flame atomic absorption spectrometry using addition standard.
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  • Hongmei YU, Wei SUN, Xiuhui ZHU, Xiaoming ZHU, Jianjun WEI
    Type: Original Papers
    2012 Volume 28 Issue 12 Pages 1219-1224
    Published: December 10, 2012
    Released: December 10, 2012
    JOURNALS FREE ACCESS
    Using multi-walled carbon nanotubes (MWCNTs) as an adsorbent has been established for the on-line separation and preconcentration Cr(III) and chromium speciation. The surface functional groups and negative charges of MWCNTs are beneficial to the adsorption of Cr(III). At pH 3.0 – 6.0, a discrimination of Cr(III) and Cr(VI) is achieved on the MWCNTs surface. Cr(III) ions are adsorbed onto the oxidized MWCNTs surface, while Cr(VI) has no affinity for the MWCNTs. The adsorbed Cr(III) is quantitatively eluted by 10% (v/v) nitric acid with detection by flame atomic absorption spectrometry. By loading a 6.0-ml sample solution, an enrichment factor of 22, a detection limit (3σ) of 1.15 μg l−1 and a precision of 1.7% RSD at the 30 μg l−1 level (n = 7) are achieved for Cr(III) within a linear range of 5 – 200 μg l−1 (r = 0.9994). After Cr(VI) has been reduced to Cr(III) with hydroxylamine hydrochloride, the total amount of chromium is obtained, and the content of Cr(VI) is given by subtraction. The procedure is validated by analyzing chromium in a certified reference material, and is further applied for the speciation of chromium in electroplating wastewater samples with satisfactory results.
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  • Ghodratollah ABSALAN, Maryam ARABI, Javad TASHKHOURIAN
    Type: Original Papers
    2012 Volume 28 Issue 12 Pages 1225-1230
    Published: December 10, 2012
    Released: December 10, 2012
    JOURNALS FREE ACCESS
    An optode was designed for an indirect determination of ascorbic acid by using neocuproine, which has been coated on transparent triacetylcellulose film as a membrane. The proposed method is based on the oxidation of ascorbic acid to dehydroascorbic acid with the Cu(II) and neocuproine reagent. The increase in the absorbance value of the optode at the maximum wavelength of 455 nm was related to the ascorbic acid concentration in aqueous samples. The sensitivity of the method was improved by using room-temperature ionic liquid, [C8MIM][PF6]. The linear dynamic range for the determination of ascorbic acid was 7.4 × 10−5 – 3.5 × 10−3 mol L−1 with a limit of detection of 2.2 × 10−5 mol L−1 (n = 10) and a response time range of 6.0 – 8.0 min. The optode was successfully applied for the determination of ascorbic acid in orange juice.
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