Analytical Sciences
Online ISSN : 1348-2246
Print ISSN : 0910-6340
ISSN-L : 0910-6340
Volume 20 , Issue 2
Showing 1-35 articles out of 35 articles from the selected issue
Rapid Communications
  • Xiaodan HAI, Mingqian TAN, Guilan WANG, Zhiqiang YE, Jingli YUAN, Kazu ...
    2004 Volume 20 Issue 2 Pages 245-246
    Published: 2004
    Released: August 06, 2004
    JOURNALS FREE ACCESS
    New silica-based europium fluorescent nanoparticles having surface amino groups were prepared by a covalent bindingcopolymerization technique. In the nanoparticles, the fluorescent Eu3+ chelate molecules were covalently bound to silicon atoms to protect the nanoparticles from dye leaking in bio-applications. The amino groups on the surface of nanoparticles made the surface modification and bioconjugation of nanoparticles easier. The nanoparticles were characterized and developed as a new type of fluorescence probe for a highly sensitive time-resolved fluoroimmunoassay (TR-FIA) of human hepatitis B surface antigen (HBsAg).
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Reviews
  • Emiko KANEKO
    2004 Volume 20 Issue 2 Pages 247-254
    Published: 2004
    Released: August 06, 2004
    JOURNALS FREE ACCESS
    In this paper our recent progress in the field of simple analytical methods is reviewed, with particular focus on the development of rapid, inexpensive, yet sensitive techniques to visualize trace elements of medical, industrial, and environmental importance. Our objective is to solve long-standing practical problems in these fields. We have repeatedly shown that visual perception is remarkably sensitive when used with our new techniques. The applicability of the proposed methods to real samples is also discussed. Making measurements visually is a method free from machinery malfunctions and serves as a simple and sensitive analytical technique, avoiding all of the practical disadvantages associated with sophisticated instrumentation as well as tedious procedures.
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  • Toshio TAKAYANAGI
    2004 Volume 20 Issue 2 Pages 255-265
    Published: 2004
    Released: August 06, 2004
    JOURNALS FREE ACCESS
    Electrophoretic migration of analytes in capillary zone electrophoresis (CZE) reflects the dissolved status of analytes in solution, and the electrophoretic mobility is controlled to develop the resolution among analytes by adding a “modifier” to the migrating solution. Such addition of modifier is essentially the utilization of molecular interactions. Precise measurement of electrophoretic mobility by CZE allows analyzing molecular interactions, and CZE apparatus is very useful for physicochemical measurements. This review focuses on the advantages on using CZE to analyze equilibrium reaction; the capillary electrophoretic method and mathematical analyses that apply acid dissociation and complex formation reactions are also validated. Ion association reactions are deeply related to analytical chemistry and separation science, and CZE has been used for the investigation of ion-ion interactions. Various types of interactions have been clarified through the CZE measurements: contributions of hydrophobicity, probability, and aromatic-aromatic interaction were quantitatively evaluated. Ion association reaction in aqueous solution also elucidates the stepwise reactions of liquid-liquid distribution of ion associates. Development and applications of ion association reaction in CZE analysis are also introduced.
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Original Papers
  • Shu TAIRA, Kenji YOKOYAMA
    2004 Volume 20 Issue 2 Pages 267-271
    Published: 2004
    Released: August 06, 2004
    JOURNALS FREE ACCESS
    We developed two DNA-conjugated polymers, one based on polyallylamine and the other on polyacrylic acid, for use in DNA chips. A 30-mer single-stranded DNA probe and thioctic acid were covalently attached to polyallylamine as sidechains. The same single-stranded DNA and 3-(pyridyldithio)propionyl hydrazide were covalently attached to polyacrylic acid as sidechains. Both DNA-conjugated polymers could be specifically immobilized onto a gold sensor substrate by a self-assembly technique. The interactions between fully matched DNA and each DNA-conjugated polymer were investigated by surface plasmon resonance. A gold surface modified with either DNA-conjugated polymer recognized fully matched DNA much better than unmatched DNA. The hybridization selectivity and efficiency of DNA-conjugated polyallylamine was optimized by adjusting the pH so as to reduce the effects of cationic polymer sidechains. The hybridization selectivity and efficiency of DNA-conjugated polymers were higher than those of a conventional immobilized thiol-based DNA. The coating of DNA-conjugated polymers reduced nonspecific adsorption of DNA by the gold substrate. DNA-conjugated polyacrylic acid was more selective toward fully matched DNA than was DNA-conjugated polyallylamine. Therefore, DNA-conjugated polymers show promise for application in novel DNA chips.
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  • Jun NAKANISHI, Mizuo MAEDA, Yoshio UMEZAWA
    2004 Volume 20 Issue 2 Pages 273-278
    Published: 2004
    Released: August 06, 2004
    JOURNALS FREE ACCESS
    We demonstrate herein a new protein conformation indicator based on biarsenical fluorescein with an extended benzoic acid moiety. The present indicator is reactive to a genetically introduced tetracysteine motif (Cys-Cys-Xaa-Xaa-Cys-Cys, where Xaa is a noncysteine amino acid) of proteins. Compared to the original biarsenical fluorescein (FlAsH) and the biarsenical Nile red analogue (BArNile), the present indicator exhibited larger fluorescence intensity changes in response to Ca2+-induced conformational rearrangements of calmodulin. A calculation of the highest occupied molecular orbital (HOMO) level of the benzoic acid moiety of the indicator molecule supports possible involvement of a photoinduced electron transfer (PET) process. These results indicate that the present indicator is useful for sensitive detection of protein conformational changes.
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  • Takatoshi SAKAI, Katsura SHINAHARA, Akira TORIMARU, Hiroyuki TANAKA, Y ...
    2004 Volume 20 Issue 2 Pages 279-283
    Published: 2004
    Released: August 06, 2004
    JOURNALS FREE ACCESS
    A sensitive and selective determination of glycyrrhizin (GC) based on surface plasmon resonance (SPR) was performed by using an anti-GC monoclonal antibody (GC-MAb) and GC-bovine serum albumin (GC-BSA) conjugate (antigen). GC-BSA was immobilized on an Au thin film of the SPR sensor chip by physical adsorption, and GC determinations were performed by an indirect competitive method. The addition of GC into the GC-MAb solution (5 µg/ml) was found to decrease the incident-angle shift sharply because of an inhibition effect of GC. The RSDs (n = 3) of each point were less than 4%. The lowest detection limit for GC by SPR was almost the same as that by ELISA, 60 - 75 ng/ml. An evaluation of the affinity constant between GC-MAb and GC using the data from ELISA and those from SPR measurements was performed. The values of the association constant (KA) from three different analyses of ELISA data and from SPR measurements are discussed in detail. As a whole, the affinity constant (KA) between GC-MAb and GC was on the order of 107 M-1.
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  • Mohamed A. F. ELMOSALLAMY
    2004 Volume 20 Issue 2 Pages 285-290
    Published: 2004
    Released: August 06, 2004
    JOURNALS FREE ACCESS
    Two novel highly selective potentiometric membrane sensors responsive to picrate ion were developed. They are based on the use of N,N′-dibenzoyl-1,4,10,13-tetraoxa-7,16-diazacyclooctadecane (DD18C6)-picrate and Kryptofix 222-picrate charge-transfer complexes as novel electroactive materials in poly(vinyl chloride) matrix membranes plasticized with o-nitrophenyloctylether or dioctylphthalate. The sensors show a Nernstian response with anionic slopes of -59.0 ± 0.1 and -58.0 ± 0.2 mV decade-1 over concentration ranges of 6.0 × 10-5 - 1.0 × 10-2 and 7.0 × 10-5 - 1.0 × 10-2 mol l-1 picrate ion and pH ranges of 5 - 11.5 and 5.5 - 11.5 for DD18C6 and Kryptofix 222 based picrate sensors, respectively. Both sensors show highly selectivity towards picrate ion over many hydrophilic and lipophilic anions, and exhibit a non-Hofmeister selectivity sequence, which is an improvement over methods reported so far. The sensors are used for the titrimetric determination of alkaloids using picrate as a titrant.
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  • Zhaohui ZHANG, Yingju LIU, Yumei LONG, Lihua NIE, Shouzhuo YAO
    2004 Volume 20 Issue 2 Pages 291-295
    Published: 2004
    Released: August 06, 2004
    JOURNALS FREE ACCESS
    The effect of the size of the molecularly imprinted polymers (MIPs) on the piezoelectric quartz crystal (PQC) sensor performance was investigated. Erythromycin imprinted polymers microspheres with different sizes were synthesized by precipitation polymerization. The size of the MIPs was characterized by using transmission electron microscope (TEM) analysis. Being coated with a poly(vinyl chloride) (PVC) membrane containing MIPs, the proposed PQC sensor can selectively adsorb the template molecule. Investigation of the performance of sensors modified with different sizes of MIPs showed that PQC sensor modified with smaller size MIPs exhibited better performance and excellent selectivity. Other influencing factors on sensor functions modified with different sizes MIPs were also investigated.
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  • Y. M. ISSA, S. I. M. ZAYED
    2004 Volume 20 Issue 2 Pages 297-300
    Published: 2004
    Released: August 06, 2004
    JOURNALS FREE ACCESS
    A new oxymetazoline (OM) ion-selective PVC membrane electrode based on the ion associate of OM with phosphotungstic acid was prepared. The electrode exhibits a linear response with a mean calibration graph slope of 57.16 mV decade-1 at 25°C within the concentration range of 1.96 × 10-5 - 1 × 10-2 M OMCl. The change in the pH within the range of 1.0 - 9.4 did not affect the electrode performance. The standard electrode potentials were determined at different temperatures and used to calculate the isothermal coefficient of the electrode (-0.001233 V). The electrode showed a very good selectivity for OM with respect to a large number of inorganic cations and compounds. The standard addition method and potentiometric titration were applied to the determination of (OM) with RSD not exceeding 1.19%.
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  • Mojtaba SHAMSIPUR, Sohrab ERSHAD, Absollah YARI, Hashem SHARGHI, Ali R ...
    2004 Volume 20 Issue 2 Pages 301-306
    Published: 2004
    Released: August 06, 2004
    JOURNALS FREE ACCESS
    The complexation of five recently synthesized hydroxy-thioxanthone derivatives with Al3+ ion was studied in a methanol solution spectrophotometrically, and the stepwise formation constants of the resulting 1:1 and 2:1 (ligand-to-metal) complexes were evaluated. The suitability of the thioxanthone derivatives as neutral ionophores for the preparation of a new Al3+ ion-selective PVC-membrane electrode was investigated, and 1-hydroxy-3-methyl-thiocanthone was selected as the best compound for this purpose. The prepared electrode exhibits a Nernstian response for Al3+ ions over a wide concentration range (2.0 × 10-2 to 2.0 × 10-6 M), with a limit of detection of 1.0 × 10-6 M. It has a very fast response time of about 5 s and can be used for at least 3 months without any considerable divergence in the potentials. The proposed membrane sensor revealed very good selectivities for Al3+ over a wide variety of other metal ions, and could be used at a working pH range of 3.4 - 5.0. It was used as an indicator electrode in potentiometric titration of aluminum ions with EDTA, and in the determination of Al3+ in different real samples.
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  • Xueping DANG, Yingliang WEI, Shengshui HU
    2004 Volume 20 Issue 2 Pages 307-310
    Published: 2004
    Released: August 06, 2004
    JOURNALS FREE ACCESS
    An acetylene black electrode modified by an adsorbed cationic surfactant, cetyltrimethylammonium bromide (CTAB), was developed. The influences of various types of surfactants on the electroreduction of O2 were investigated. It was demonstrated that a cationic surfactant, CTAB, on the surface of the electrode could significantly decrease the overpotential of dioxygen reduction, and the reduction peak current of O2 was also remarkably increased. The reduction of O2 at a CTAB modified acetylene black electrode was studied using cyclic voltammetry, chronocoulometry and controlled potential coulometry. The total number of electrons, the exchange current density ( jo) and the transfer coefficient (α) for reduction of O2 at the surface of this modified electrode were determined.
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  • Osamu SAKURADA, Yasutake KATO, Noriyoshi KITO, Keiichi KAMEYAMA, Toshi ...
    2004 Volume 20 Issue 2 Pages 311-314
    Published: 2004
    Released: August 06, 2004
    JOURNALS FREE ACCESS
    Zirconium oxy-salts were hydrolyzed to form positively charged polymer or cluster species in acidic solutions. The zirconium hydrolyzed polymer was found to react with a negatively charged polyelectrolyte, such as poly(vinyl sulfate), and to form a stoichiometric polyion complex. Thus, colloidal titration with poly(vinyl sulfate) was applied to measure the zirconium concentration in an acidic solution by using a Toluidine Blue selective plasticized poly(vinyl chloride) membrane electrode as a potentiometric end-point detecting device. The determination could be performed with 1% of the relative standard deviation. The colloidal titration stoichiometry at pH ≤ 2 was one mol of zirconium per equivalent mol of poly(vinyl sulfate).
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  • Shuhao WANG, Lingyun DU, Liangyu WANG, Huisheng ZHUANG
    2004 Volume 20 Issue 2 Pages 315-317
    Published: 2004
    Released: August 06, 2004
    JOURNALS FREE ACCESS
    A simple rapid and accurate flow injection inhibitory chemiluminescence method has been developed for the determination of dopamine hydrochloride based on its inhibition of the chemiluminescence from the luminol-potassium hexacyanoferrate(III) system. The linear range of determination is 4.0 × 10-9 - 4.0 × 10-7 g ml-1 for dopamine hydrochloride and the detection limit is 1.14 × 10-9 g ml-1. The method has been applied to determine the content of dopamine in pharmaceutical preparation with satisfactory results.
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  • Zhouping WANG, Zhujun ZHANG, Zhifeng FU, Luqiu FANG, Xiao ZHANG
    2004 Volume 20 Issue 2 Pages 319-323
    Published: 2004
    Released: August 06, 2004
    JOURNALS FREE ACCESS
    A novel and highly sensitive method for the determination of phenformin over the range of 6 × 10-9 - 1 × 10-5 g ml-1 in pharmaceutical formulations with flow-injection chemiluminescence (CL) detection is proposed. The method is based on the CL produced during the oxidation of N-bromosuccinimide (NBS) in an alkaline medium in the presence of fluorescein as an effective energy transfer agent. The use of cetyltrimethylammonium bromide (CTAB) as a sensitizer enhances the signal magnitude by about 100 times. The detection limit is 2 × 10-9 g ml-1 (3 σ) with a relative standard deviation of 2.3% (n = 11) at 1 × 10-7 g ml-1 phenformin. Ninety samples can be determined per hour. The method was evaluated by carrying out a recovery study and by the analysis of commercial formulations. The obtained results compared well with those by an official method, and demonstrated good accuracy and precision. The possible CL mechanism of the proposed system was also briefly analyzed.
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  • Mayumi MINAMISAWA, Shoichiro YOSHIDA, Nobuharu TAKAI
    2004 Volume 20 Issue 2 Pages 325-328
    Published: 2004
    Released: August 06, 2004
    JOURNALS FREE ACCESS
    We studied the simultaneous quantitative analysis of biologically active substances, such as nicotinic acid, trigonelline, caffeine, qunolinic acid and tannic acid and pyrogallic acid, in several roasted coffees by an HPLC/diode-array system with a home-made sol-gel and ODS-2 columns. A simple method for simultaneous quantitative analysis of biologically active substances in the coffee brew became feasible by an HPLC/diode-array system with a sol-gel column at a single wavelength of 210 nm. The most efficient condition of the Rs value was above 1.05 when two sol-gel columns were connected. In addition, the elution behavior of nicotinic acid in brew extracted from commercially available coffee beans suggests the thermal decomposition process during roasting, and indicated the maximum value for full city roasted coffee.
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  • A. Rehber TÜRKER, Sitki BAYTAK
    2004 Volume 20 Issue 2 Pages 329-334
    Published: 2004
    Released: August 06, 2004
    JOURNALS FREE ACCESS
    A sensitive solid-phase extraction technique (SPE) for the enrichment of Fe(III), Co(II), Mn(II) and Cr(III) prior to atomic absorption spectrometric analysis is described. Escherichia coli immobilized on Amberlite XAD-4 was used as a solid-phase extractor. The effects of the pH, amount of solid-phase, eluent type and volume of the sample solution on the recovery of the metal ions were investigated. The effect of diverse ions was also investigated. The recoveries of Fe(III), Co(II), Mn(II) and Cr(III) under the optimum conditions were found to be 99 ± 2, 99 ± 3, 98 ± 2, 98 ± 3%, respectively, at the 95% confidence level. The detection limits of the metal ions were found as to be 2.4, 3.8, 1.3 and 1.7 ng ml-1 for Fe(III), Co(II), Mn(II) and Cr(III) respectively, by applying a preconcentration factor of 25. The proposed enrichment method was applied to the determination of analytes in Atatürk Dam water samples, and alloy samples (RSD < 5%). The accuracy of the method was verified on certified alloy samples (NBS SRM 85b and NBS SRM 59a). The analytes were determined with a relative error lower than 5% in water and alloy samples.
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  • Yoshihiro SAITO, Ai TAHARA, Mitsuhiro OGAWA, Motohiro IMAIZUMI, Kazuhi ...
    2004 Volume 20 Issue 2 Pages 335-339
    Published: 2004
    Released: August 06, 2004
    JOURNALS FREE ACCESS
    Fibrous synthetic polymers have been introduced as the support material for packed capillaries in gas chromatography. The filaments of the polymers were packed longitudinally into a fused-silica capillary, followed by the conventional coating process for open-tubular capillaries. With various polysiloxane-based polymeric materials coated onto these filaments, it was demonstrated that the retentivity was significantly improved over conventional wall-coated capillaries of the same length and that the selectivity can be tuned by selecting different coating materials chosen for the various purposes. The results clearly showed the contribution of the fibrous support and the polymer-coating to the retention of analytes. They also showed the bright possibility for a novel usage of fine fibrous polymers as the support material, which can be combined with a newly-synthesized coating materials designed for particular separations.
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  • Masahiro NAGAI, Masahito SUGIYAMA, Toshitaka HORI
    2004 Volume 20 Issue 2 Pages 341-344
    Published: 2004
    Released: August 06, 2004
    JOURNALS FREE ACCESS
    Phosphate, 3 - 10 nmol, in 1 dm3 of natural-water samples was quantitatively collected along with 10 µmol of Fe(III) ion onto a silica-gel collector in the pH range of 5.4 - 6.2. The amount of Fe(III) ion needed was limited to such a low level that the Pyrocatechol Violet method could be applied without removing the Fe(III) ion, providing a superior determination method for phosphate. Surface-water samples of the north basin of Lake Biwa and the Tanabe Bay in the Wakayama prefecture were selected as being representative of natural water with extremely low phosphate concentrations, and were found to have phosphate concentrations of 3.68 and 4.31 nmol dm-3, respectively.
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  • B. Ramachandra REDDY, P. RADHIKA, J. Rajesh KUMAR, D. Neela PRIYA, K. ...
    2004 Volume 20 Issue 2 Pages 345-349
    Published: 2004
    Released: August 06, 2004
    JOURNALS FREE ACCESS
    Cyanex 923 has been proposed as a sensitive analytical reagent for the direct extractive spectrophotometric determination of cobalt(II). Cobalt(II) forms a blue-colored complex with Cyanex 923 in the organic phase. The maximum absorbance of the complex is measured at 635 nm. Beer’s law was obeyed in the range 58.9 - 589.0 µg of cobalt. The molar absorptivitiy and Sandell’s sensitivity of the complex was calculated to be 6.79 × 102 l mol-1 cm-1 and 0.088 µg cm-2, respectively. The nature of the extracted species was found to be Co(SCN)2·2S. An excellent linearity with a correlation coefficient value of 0.999 was obtained for the Co(II)-Cyanex 923 complex. Stability and regeneration of the reagent (Cyanex 923) for reuse is the main advantage of the present method. The method was successfully applied to the determination of cobalt in synthetic mixtures and pharmaceutical samples was found to give values close to the actual ones. Standard alloy samples, such as high-speed tool BCS 484 and 485, have been tested for the determination of cobalt for the purpose of validating the present method. The results of the proposed method are comparable with atomic absorption spectrometry and were found to be in good agreement.
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  • Roseli Martins SOUZA, Carmem Lúcia P. da SILVEIRA, Ricardo Quei ...
    2004 Volume 20 Issue 2 Pages 351-355
    Published: 2004
    Released: August 06, 2004
    JOURNALS FREE ACCESS
    The quantification of trace elements in used lubricating oil is useful for evaluating the wearing of specific components of engines. In the present work, inductively coupled plasma optical emission spectrometry (ICPOES) was used for determining five refractory elements (Ni, Mo, Cr, V and Ti) in lubricating-oil samples. The methodology was developed while aiming at the introduction of such organic samples into the ICP as emulsions. Several nebulization systems were tested with clear advantage for Meinhard K3 coupled with a cyclonic spray chamber. The carbon deposition on the injector tip as well as the plasma background was minimized through careful optimization of the Ar and O2 gas mixture flows into the plasma. The optimization of instrumental and experimental parameters allowed quantification using calibration curves prepared with analyte inorganic standards. An internal standard (Sc) was used to correct the matrix effects and signal fluctuations. The limits of detection (3Sb/m), in the ng g-1 range were obtained for all five elements. The methodology was validated through an analysis of standard reference materials (SRM 1084a, 1085a and 1085b). Good analyte recoveries (from 92.6 to 104.7%) were achieved. Comparison studies against established ICPOES methodologies (sample acid decomposition or sample direct dilution in an organic solvent) have shown that the proposed methodology present clear advantages in terms of simplicity of sample preparation, overall analysis time, and the use of inorganic standards for calibration instead of expensive metallorganic standards.
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  • Tianlin YANG, Xishi TAI, Wenwu QIN, Weisheng LIU, Minyu TAN
    2004 Volume 20 Issue 2 Pages 357-361
    Published: 2004
    Released: August 06, 2004
    JOURNALS FREE ACCESS
    A new Schiff-base ligand with a tripodal structure, N,N′,N″-tri(3-indolemethanal)triaminotriethylamine (TTAIM), was synthesized. Its fluorescence intensity with terbium(III) was increased by about two orders of magnitude in the present of sodium acetate (NaAc). After the adding of the organic solvent dimethyl sulfoxide (DMSO) to the above system, leading to Tb3+ the fluorescence was further enhanced by about 16 fold. The spectrofluorimetric determination of a trace amount of Tb3+ based on this phenomenon was carried out. The excitation and emission wavelengths were 330 nm and 545 nm, respectively. Under the optimal conditions, the fluorescence intensities varied linearly with the concentration of Tb3+ in the range of 5.7 × 10-11 -6.3 × 10-6 mol L-1 with a detection limit of 5.0 × 10-11 mol L-1. The interferences of some rare earth metals and other inorganic ions were described. The method is a selective, sensitive, rapid and simple analytical procedure for the determination of terbium(III) in a high-purity yttrium oxide and synthetic sample. The mechanism for the fluorescence enhancement was also studied.
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  • Yasuyuki MIURA, Mutsuo FUJISAKI, Paul R. HADDAD
    2004 Volume 20 Issue 2 Pages 363-367
    Published: 2004
    Released: August 06, 2004
    JOURNALS FREE ACCESS
    A photometric method has been developed for the determination of sulfide at 10-5 mol dm-3 levels, which is based on the reaction of sulfide with a given excess amount of bismuth(III) to form a precipitate of bismuth(III) sulfide and on the spectrophotometric measurement of the residual bismuth(III) at 335 nm after extracting with bismuthiol II reagent from an aqueous solution containing acetate buffer into benzene. The presence of sulfite and thiosulfate up to 0.002 mol dm-3 did not cause any interference in the determination of sulfide, because both sulfite and thiosulfate do not produce any precipitate with bismuth(III). A linear calibration plot with a negative slope was obtained for sulfide over the range of 5.00 × 10-7 - 3.00 × 10-5 mol dm-3 (16.0 - 960 ppb). An experimental calibration plot was in accord with the theoretical plot, taking into account the known excess of bismuth(III), showing that the reaction of sulfide with bismuth(III) proceeded to completion. The relative standard deviation of results from 10 replicate determinations of standard sulfide (2.00 × 10-5 mol dm-3) was 0.44%. The proposed method was successfully applied to the determination of sulfide in hotspring water samples without any pretreatment.
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  • Kazuhiko FUJIWARA, Hitoshi WATARAI
    2004 Volume 20 Issue 2 Pages 369-372
    Published: 2004
    Released: August 06, 2004
    JOURNALS FREE ACCESS
    The interfacial adsorption and dimerization behavior of tetraphenylporphinatomanganese(III)chroride (Mn(TPP)Cl) in the toluene/water two phase system was studied. The absorption spectra of the porphyrin complex in the organic phase were blue shifted with increasing of pH in the aqueous phase, suggesting the formation of the µ-oxo dimer. The interfacial species in these systems were examined by means of UV/vis external reflection (ER) spectrophotometry. ER spectral maxima were also blue shifted with the increase in pH, whereas the shape of the ER spectra in the basic conditions was different from that of the µ-oxo dimer. The observed results suggest that the hydroxide-coordinated monomer, Mn(TPP)OH, was generated from the Mn(TPP)(H2O)+ at the interface under the basic conditions and that was further converted to the µ-oxo dimer, which was soluble into the toluene phase.
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