BUNSEKI KAGAKU Abstracts

Vol. 52 No. 10

October, 2003


Research Papers

Dependence of photoelectron diffraction of single molecule adsorbing Ni(111) surface on the sources of Cr-Lα and Al-Kα lines

Hitoshi Nakamura1,2, Keiji Tamura2,4, Hideshi Ishii2, Masanori Owari2,3, Chuhei Oshima4 and Yoshimasa Nihei1,2

1 Faculty of Science and Technology, Tokyo University of Science, 2641, Yamazaki, Noda-shi, Chiba 278-8510
2 Institute of Industrial Science, University of Tokyo, 4-6-1, Komaba, Meguro-ku, Tokyo 153-8505
3 Environmental Science Center, University of Tokyo, 7-3-1, Hongo, Bunkyo-ku, Tokyo 113-0033
4 Faculty of Science and Engineering, Waseda University, 3-4-1, Okubo, Shinjuku-ku, Tokyo 169-0051

(Received 19 May 2003, Accepted 31 July 2003)

In order to elucidate the dependence of X-ray photoelectron diffraction (XPED) method on the X-ray source, we investigated XPED patterns from a h-BN/Ni(111) surface by using both Cr-Lα (572.8 eV) and Al-Kα (1486.6 eV). As the first step Ni3p photoelectron diffraction patterns were measured and calculated from a substrate Ni(111) by using both sources. Forward scattering peaks and Kikuchi-like bands were clearly observed in both experimental and theoretical patterns excited by Al-Kα. On the contrary, these features of Cr-Lα excited XPED patterns were more diffuse. This suggests that the usage of a lower energy X-ray source improves XPED structural analysis on ultrathin films composed of light elements.

Keywords : X-ray photoelectron diffraction; multiple scattering cluster with spherical wave; h-BN/Ni(111); Kikuchi-like band; forward scattering peak.


Ion-transfer voltammetry of histamine and anti-histamine drugs at an oil/water interface

Ryuji Tsukamoto1 and Fumiyo Kusu1

1 School of Pharmacy, Tokyo University of Pharmacy and Life Science, 1432-1, Horinouchi, Hachioji-shi, Tokyo 192-0392

(Received 3 May 2003, Accepted 12 August 2003)

Ion-transfer volutammetry at a nitrobenzene/water interface was performed to study the ion-transfer reaction and the adsorption of histamine and anti-histamine drugs, such as dl-chlorpheniramine, clemastine, diphenhydramine, cyproheptadine, meclizine, promethazine, ketotifen, and terfenadine. Ion-transfer volutammograms showed that all anti-histamine drugs gave an anodic wave at a potential less positive than that of histamine. Electrocapillary curves showed that the anti-histamine drugs were adsorbed on the interface with great facility. We assessed the effects of the ionization of these drugs on the ion-transfer reaction and adsorption by ion-transfer volutammograms and electrocapillary curves, respectively. Based on these results, the half-wave potentials for the drugs at pH 4 were plotted against the calculated log KD values obtained by using PALLSA (CompuDrug International). The half-wave potentials had a strong correlation with the calculated log KD values. We conclude that the half-wave potentials determined by the present method would be a more reliable parameter of hydrophobicity for neutral and ionic forms of drugs when dealing with structure-activity relationships of drugs compared to experimental log P values obtained by the conventional methods.

Keywords : ion-transfer voltammetry; oil/water interface; histamine; anti-histamine drugs.


Flow-injection spectrophotometry of cadmium in river water with tetraphenyl-porphinetetrasulfonic acid using on-line electrolytic preconcentration

Masashi Ito1, Masayuki Itagaki1 and Kunihiro Watanabe1

1 Department of Pure and Applied Chemistry, Faculty of Science and Technology, Tokyo University of Science, 2641, Yamazaki, Noda-shi, Chiba 278-8510

(Received 25 June 2003, Accepted 13 August 2003)

The determination of cadmium in river water was investigated by a flow-injection analysis. In general, it is difficult to determine cadmium in an eluate by uv-vis spectrophotometry, because the eluate includes high concentrations of acid, alkali or complex agents. Therefore, a concentration method was investigated by electrolytic deposition, which does not require an eluant. Dual electrolytic cells were used in this flow system. One of them was for removing copper ion and other ions which interfere with the determination of cadmium. The other cell was used for concentrating cadmium in river water. After cadmium was deposited on platinum electrode for 20 min at -0.8 V vs. SSE, it was eluted for 2 min at 1.5 V from the electrode. The cadmium obtained from the electrode was determined with tetraphenyl-porphinetetrasulfonic acid(TPPS) by spectrophotometry at 434 nm. 2,2'-Bipyridine was added into the sample solution as a catalyst for a Cd-TPPS reaction. The calibration curve was linear at over the range of 0 to 10 ppb. The determination limit of cadmium was 0.45 ppb. The RSD of 10 ppb Cd was 2.1% (n=5). The proposed method was applied to the determination of river water, including a standard sample.

Keywords : electrolytic concentration cell; cadmium; TPPS; flow injection analysis; on-line concentration.


Notes

Decomposition of methylene blue by new porous photocatalysts and analysis of decomposed products using high-performance liquid chromatography and mass spectrometry

Satoshi Horikiri1, Norio Teshima1, Yurie Saruki2, Harumitsu Nishikawa3 and Tadao Sakai1

1 Department of Applied Chemistry, Aichi Institute of Technology, 1247, Yachigusa, Toyota-shi, Aichi 470-0392
2 Noritake Company Limited, 300, Higashiyama, Miyoshi-cho, Aichi 470-0293
3 Gifu Prefectural Institute of Health and Environmental Science, 1-1, Naka-Fudogaoka, Kagamihara-shi, Gifu 505-0037

(Received 9 May 2003, Accepted 24 July 2003)

Three photocatalysts were newly synthesized. The materials consisted of Al2O3 or SiC and anatase-type TiO2. The characteristics of the materials were analyzed by X-ray spectroscopy and TEM. Also, the photocatalytic activity upon the decomposition of methylene blue was investigated by measuring the decomposition rate of methylene blue with the UV(λ 369 nm) irradiation time. In addition, the derivatives of methylene blue produced after 2 and 4 hours of irradiation were analyzed by HPLC and MS. As a result, azur A and azur B were observed.

Keywords : photocatalysis; new porous inorganic material; methylene blue; HPLC; MS.


Adsorption of mercury on used tea leaves and coffee beans

Takuji Kiyohara1, Katsuro Anazawa1, Hayao Sakamoto1 and Takashi Tomiyasu1

1 Department of Earth and Environmental Sciences, Faculty of Science, Kagoshima University, 1-21-35, Korimoto, Kagoshima-shi, Kagoshima 890-0065

(Received 9 May 2003, Accepted 31 July 2003)

The adsorption of mercury(II) from aqueous solutions on green tea leaves, coffee beans and activated carbons has been studied comparatively. The adsorption capacity of those adsorbents was little affected by pH and EDTA. The coffee beans and the activated carbons adsorption capacity were highly affected by chloride ion, whilst the green tea leaves were less affected. The adsorption data obtained from equilibrium experiments were well-fitted to Freundlich isotherms.

Keywords : mercury; adsorption; tea leaves; coffee beans; activated carbons.


Laser pyrolysis gas chromatography system using a pulsed Nd:YAG laser and its analytical performance

Hisako Murakami1, Hironori Kurata1 and Mikio Kuzuya1

1 Department of Electronic Engineering, College of Engineering, Chubu University, 1200, Matsumoto-cho, Kasugai-shi, Aichi 487-8501

(Received 8 May 2003, Accepted 2 August 2003)

A laser pyrolysis gas chromatograph (LPGC) system has been developed, which allowed for the direct analysis of solid samples. The LPGC system consists of a Q-switched Nd:YAG laser (pulse energy, 0~230 mJ; repetition rate, 1~15 Hz) as a fragmentation source, a gas chromatograph, a sample chamber, and a data-acquisition/processing system. A commercial tube-furnace type pyrolyzer was used as the sample chamber, and the sample was placed in a quartz tube. The LPGC system was applied to the analysis of a polystyrene sample, and its analytical performance were investigated. The chromatographs obtained from polystyrene showed the characteristic component peaks of ethylene, benzene, toluene, and styrene monomer. The relative standard deviations of the peak intensity, the FWHM, and the retention time were in the ranges of 5.3~22%, 3.1~16%, and 0.06~1.1%, depending on the components, respectively. The effects of the laser energy and laser focusing on the chromatograms were investigated. The results showed that moderate energy and defocusing of the laser radiation brought about an increase in the signal intensity.

Keywords : laser pyrolysis gas chromatograph; Nd:YAG laser; laser energy; laser focusing; polystyrene.


Simple spectrophotometric determination of nonionic surfactants with a cationic azo dye

Maiko Nakata1, Yoshiyuki Murata1, Mikiro Tada2 and Yasuaki Shimoishi1

1 Bioresorces Chemistry, Faculty of Agriculture, Okayama University, 1-1-1, Tsushima-naka, Okayama-shi, Okayama 700-8530
2 Graduate School of Natural Science and Technology, Okayama University, 3-1-1, Tsushima-naka, Okayama-shi, Okayama 700-8530

(Received 9 June 2003, Accepted 5 August 2003)

A simple spectrophotometric method for the determination of polyoxyethylene nonionic surfactants, such as TritonX-100 with 1-(p-phenylphenacyl)-4-(4-aminonaphthylazo)-pyridinium bromide(PPAP), was developed. PPAP was synthesized by quarternizing 4-(4-aminonaphthylazo)-pyridine with p-phenylphenacyl bromide. Because PPAP was easily associated with nonionic surfactants to produce a blue ion associate in aqueous solution, the concentration of nonionic surfactants were determined by measuring the absorbance of ion associates at 612 nm. The apparent molar absorptivity of the TritonX-100 ion associate was 1.0×103 dm3 mol-1 cm-1 at 612 nm. The calibration graph for TritonX-100 was linear over the range from 6.0×10-5 to 8.0×10-4 M, and the relative standard deviation for 5.6×10-4 M of TritonX-100 was 2.0%. The proposed method was applied to the determination of nonionic surfactants in commercial domestic detergents.

Keywords : spectrophotometry; nonionic surfactant; 1-(p-phenylphenacyl)-4-(4-aminonaphthylazo)-pyridinium bromide; TritonX-100; Briji 35.


Separation of catechins by temperature-responsive chromatography

1 Physical Pharmaceutical Chemistry, Kyoritsu College of Pharmacy, 1-5-30, Shibakoen, Minato-ku, Tokyo 105-8512
2 Institute of Advanced Biomedical Engineering and Science, Tokyo Women's Medical University, 8-1, Kawadacho, Shinjuku-ku, Tokyo 162-8666

(Received 12 May 2003, Accepted 21 August 2003)

We have developed a new method of chromatography, temperature-responsive chromatography, using packing materials modified with poly(N-isopropylacrylamide) (PNIPAAm). The temperature-responsive polymer, PNIPAAm, shows a reversible and sharp phase transition in an aqueous solution. The PNIPAAm-modified stationary phase alters the properties of the surface from hydrophilic to hydrophobic in response to temperature changes at the phase-transition temperature. In this study, we examined the separation of five catechins (epigallocatechin, epicatechin, catechin, epigallocatechin gallate and epicatechin gallate) using a PNIPAAm-modified column without changing the composition of the mobile phase. In this method, interactions between catechins and the stationary phases were controlled by the temperature. The retention times of all catechins were retarded, because the interaction increased at elevated temperature. We achieved the separation of catechins using only an aqueous solution as a mobile phase by temperature-responsive chromatography.

Keywords : temperature-responsive polymer; poly(N-isopropylacrylamide); catechins; short column.


Solvent effect on the UV-Vis absorption spectra of an alkylquinolinium salt of [Ni(dmit)2]

Jun Iwata1, Yuji Soneta1 and Kazuo Miyamura1

1 Department of Chemistry, Faculty of Science, Science University of Tokyo, 1-3, Kagurazaka, Shinjuku-ku, Tokyo 162-8601

(Received 13 May 2003, Accepted 21 August 2003)

Significant solvatochromism has been observed in the UV-Vis spectra of an alkylquinolinium salt of [Ni(dmit)2]. In particular, a large blue shift was observed when chloroform was used as the solvent. From a UV-Vis spectral analysis, it was concluded that the [Ni(dmit)2] anion forms adducts with cations, and that the change in the electronic state induced by the formation of adducts was responsible for the solvatochromism. In the course of our study, it was found that the oxidation of the complex by oxygen in air was strongly accelerated by the presence of methanol. An investigation of the reaction kinetics of this reaction revealed that the reaction rate is proportional to the methanol concentration.

Keywords : dmit; solvatochromism; nickel; kinetics.


Technical Letters

An attempt to verify the restoration of underground water veins by using a strontium tracer

Shin-ichiro Nagashima1, Yoshiko Yano1 and Toshihiko Takura2

1 Department of Chemical Science and Engineering, Tokyo National College of Technology, 1220-2, Kunugida-cho Hachioji-shi, Tokyo 193-0997
2 DAIICHIKASEI Co., Ltd, 1-13-1, Fujimi-cho, Gyoda-shi, Saitama 361-0021

(Received 2 June 2003, Accepted 9 August 2003)

This research aimed to verify the restoration of a water vein in Hachioji-Minamino City. The developer of the new town had made an attempt to link some separated water veins with artificial strata of gravel. An aqueous solution of Sr2+ was injected into a probable upstream point (B12-3) of a vein, and every 2 weeks after that the Sr2+ levels in water samples from four probable downstream points were analyzed. About 40 days after at one (S-16) of the four points, an extraordinary increase in the Sr2+ concentration was observed. At the same time, the concentration levels of Ca2+, Mg2+ and Na+ and the electric conductivity suddenly increased. These show that the two points, B12-3 and S-16, are linked to each other and that Sr2+ is a suitable stable indicator for analyzing underground water veins. The concentration levels of the above-mentioned cations were also observed every month for underground water samples from several sampling points where the water vein was supposed to be independent of the present tracer investigation. The quartile deviations for the observed values were shown mostly within 5% for a very long time, a max. of 34 months.

Keywords : underground water; tracer; strontium; ICP-AES.


In-tube solid-phase microextraction/electrothermal atomic absorption spectrometry of copper(II) using teflon tube after complexation with oxine-5-sulfonate

Kohki Kobayashi1, Isoshi Nukatsuka1, Fumihide Miyashita2 and Kunio Ohzeki1

1 Department of Material Science and Technology, Faculty of Science and Technology, Hirosaki University, 3, Bunkyo-cho, Hirosaki-shi, Aomori 036-8561
2 Analytical Applications Department, Shimadzu Corporation, 1, Nishinokyo-Kuwabaracho, Nakagyo-ku, Kyoto-shi, Kyoto 604-8511

(Received 16 June 2003, Accepted 25 August 2003)

A Teflon tube of 1.5 m in length and 0.5 µm in inner diameter was used to extract Cu(II) after complexation with oxine-5-sulfonate in in-tube solid-phase microextraction/electrothermal atomic absorption spectrometry. Prior to extraction, Zephiramine was loaded onto the inner wall of the Teflon tube, the sample solution was adjusted to pH 5.6, and then placed in a ca. 1 or 2-ml sample vessel. Subsequently, extraction was carried out in such a way that the sample solution was sucked into the Teflon tube and discharged to the original vessel with a syringe pump included in the auto-sampler. The suction and discharge actions were repeated several times to attain equilibrium and to improve the amounts of copper extracted. The percent extraction after equilibrium was 79% for a 200-µl sample solution. The effect of the sample volume was examined in the range of 0.5~2.0 ml. The suction and discharge actions were repeated 7 times with 295 µl of the sample solution, which was the inner volume of the Teflon tube. The results showed that the amounts of copper extracted increased with increasing volume of the sample solution up to 1.0 ml, although the percent extraction decreased with the sample volume. When copper extracted from 1.0 ml of a 0.3 ng ml-1 sample solution was eluted by 30 ml of methyl acetate (10% methanol), a reasonable repeatability with a relative standard deviation of 2.8% (n=3) was obtained. A linaer calibration graph was also obtained in the range of 0~0.5 ng ml-1 Cu(II). The detection limit(3σ) was 0.01 ng ml-1. The slope of the calibration graph was 14.2-times greater than that obtained by injecting 20 µl of standard solutions into the atomization furnace.

Keywords : Teflon tube; electrothermal atomic absorption spectrometry; copper; oxine-5-sulfonic acid; in-tube solid-phase microextraction.


Research Papers

Liquid chromatography/mass spectrometric analysis of 2-nitrophenylhydrazide derivatives of low-molecular organic acids

Hiroki Saitoh1 and Keiji Gamoh1

1 Faculty of Education, Kochi University, 2-5-1, Akebono-cho, Kochi-shi, Kochi 780-8520

(Received 14 April 2003, Accepted 1 August 2003)

In chromatographic analysis, a suitable derivatization of the functional groups has sometimes been used to enhance the sensitivity and selectivity for detection. Transforming low molecular organic acids to the corresponding 2-nitrophenylhydrazide derivatives has been more extensively used as a suitable derivatization method for liquid chromatographic UV-VIS detection. In the present study, liquid chromatography/mass spectrometric (LC-MS) detection with electro spray ionization was successfully applied to the analysis of low-molecular organic acids, glycolic, acetic, lactic, 2-hydroxy-n-butyric, propionic and n-butyric acid as their 2-nitrophenylhydrazide derivatives. Of a range of analytical conditions that were tested, the optimum results were obtained by using reversed-phase liquid chromatography and a mixture of methanol/water or methanol/ammonium formate. The positive- and negative-ion spectra of 2-nitrophenylhydrazides of the organic acids showed molecular-related ions, [M+H]+ and [M-H]-, whose ions were the most abundant, respectively. The effects of the chromatographic and ionization parameters, mobile phase, concentration of ammonium formate, pH and cone voltage on the sensitivity and linearity were examined. Linear plots of the peak area versus the concentration were obtained for MS detection over the range of 0.05~10 µM for propionic acid and 0.1~10 µM for lactic acid. Full-scan mass spectra were readily obtained from 34 nM of n-butyric acid derivative, while a limit of detection of 1.4 nM (signal-to-noise ratio 3) was attained in the selected-ion monitoring mode. These results showed that 2-nitrophenylhydrazide of low molecular organic acids contributes to the enhancement of the LC-MS detection compared with their UV-VIS detection.

Keywords : LC-MS; 2-nitrophenylhydrazide derivative; low-molecular organic acid; electrospray.


Technical Papers

Determination of trace refractory metal elements in high-purity iron by inductively coupled plasma mass spectrometry

Kunikazu Ide1, Yoshisuke Nakamura1, Shin-ichi Hasegawa1 and Hitoshi Yamaguchi1

1 National Institute for Materials Science (NIMS), 1-2-1, Sengen, Tsukuba-shi, Ibaraki 305-0047

(Received 17 April 2003, Accepted 8 July 2003)

The determination of trace amounts of refractory metal elements (Ti, V, Zr, Nb, Mo and Ta) in high-purity iron by inductively coupled plasma mass spectrometry (ICP-MS) was examined. We examined a separating technique involving trace amounts of refractory metal elements from a high-purity iron matrix using the cupferron coprecipitation separation method and the measurement conditions of ICP-MS. Using the established analysis method, after 150 cm3 of hydrochloric acid (1+4) was added to 1 g of high-purity iron sample, they were decomposed on a 453 K hot plate. After the sample solutions were cooled at room temperature, an ascorbic acid solution and cupferron solutions were added to 10 cm3 portions, and then filtered. The paper filter and sediment were then added to 10 cm3 of nitric acid and 10 cm3 of perchloric acid, and dried through evaporation. After 150 cm3 of hydrochloric acid (1+4) was added to salt, it was dissolved; this operation was then repeated again. After 2 cm3 of nitric acid was added to this salt and it was dissolved, it was dried through evaporation. After the process of evaporation to dryness was performed 3 times, nitric acid (1+100) was added to the salt and dissolved. The sample solution was measured by ICP-MS. The concentration of the iron matrix in sample solution was decreased to about 200 µg cm-3, and it didn't change. The background signal at mass 90 was decreased by nitric acid-treatment process, which enabled this difficult experiment to be carried out. The recovery rates of 6 added elements were 99% for Ti, 95% for V, 98% for Zr, 98% for Nb, 96% for Mo and 96% for Ta, respectively. The detection limits were 0.08 ng cm-3 for Ti, 0.009 ng cm-3 for V, 0.01 ng cm-3 for Zr, 0.008 ng cm-3 for Nb, 0.01 ng cm-3 for Mo and 0.004 ng cm-3 for Ta, respectively.

Keywords : inductively coupled plasma mass spectrometry; refractory metal elements; high purity iron sample; cupferron coprecipitation separation; titanium, vanadium, zirconium, niobium, molybdenum and tantalum.


Notes

Reaction between pH indicators with a large pKa value and human serum albumin and its application to the determination of the serum albumin concentration

Yuji Suzuki1

1 Department of Medical Technology, Saitama Prefectural University Junior College, 820, Sannomiya, Koshigaya-shi, Saitama 343-8540

(Received 9 May 2003, Accepted 7 July 2003)

The reaction between four pH indicators with a large pKa value and human serum albumin and its application to the determination of the serum albumin concentration were studied. In the reaction of Bromothymol Blue (BTB), Phenol Red, Cresol Red and Thymol Blue with serum albumin, although a change in the color shade did not occur, the absorbance of the reaction mixture decreased. Since this absorbance decrease was largest in the reaction of BTB(the molar absorbance decrease at pH 7.4 was 7.59×104 l mol-1 cm-1), which was sufficiently sensitive to measure the serum albumin concentration, the BTB color reagent at pH 7.4 was applied to its determination. The measurement values by the BTB method correlated with those by the dye-binding method using the Bromocresol Green method(r=0.965, y=1.21x-4.25, n=90) and with those by a method using Bromocresol Purple(r=0.953, y=1.04x+3.56, n=90). The mean value of the BTB method (41.8 g/l) was higher than those of the Bromocresol Green method (38.1 g/l) and the Bromocresol Purple method(36.6 g/l). Since the reaction of BTB was carried out at pH 7.4, where serum protein does not precipitate, the addition of a detergent for preventing the precipitation of serum protein is not required. Therefore, the use of this color reagent contributes to decreasing water pollution by the detergent and acid used in the conventional methods.

Keywords : serum albumin; determination method; dye-binding method; Bromothymol Blue.


Technical Letters

Comparison between passive and active samplers for the determination of formaldehyde in indoor air by field test

Hideaki Kitami1, Tetsuo Watanabe2, Takio Kitahara3, Yoshimi Ishihara3 and Jiro Takano3

1 Sougou Kankyou Bunseki Co., Ltd., 1-13-2, Kamoi, Midori-ku, Yokohama-shi, Kanagawa 226-0003
2 Department of Resources and Environmental Science, School of Humanities and Culture, Tokai University, 1117, Kitamaname, Hiratsuka-shi, Kanagawa 259-1292
3 Derpartment of Chemistry, School of Science, Tokai University, 1117, Kitamaname, Hiratsuka-shi, Kanagawa 259-1292

(Received 27 February 2003, Accepted 27 June 2003)

Keywords : formaldehyde (HCHO); sampler; HPLC-UV; 2,4-dinitorophenylhydrazine (DNPH); indoor air; field test.


Determination of 210Pb, 210Po, 232Th, 230Th, 228Th, 238U, 235U and 234U with alpha ray spectrometry in manganese nodule standard rock sample JMn-1

Tsutomu Miura1, Kazushige Nakayama2 and Hiroshi Kirita2

1 Inorganic Analytical Chemistry Division, National Metrology Institute of Japan, National Institute of Advanced Industrial Science and Technology, Tsukuba Central 3-10, 1-1-1, Umezono, Tsukuba-shi, Ibaragi 305-8563
2 Japan Chemical Analysis Center, 295-3, Sanno, Inage-ku, Chiba-shi, Chiba 263-0002

(Received 27 May 2003, Accepted 27 July 2003)

210Pb, 210Po, 232Th, 230Th, 228Th, 238U, 235U and 234U in Geological Survey of Japan manganese nodule standard rock sample JMn-1 were determined by radioactive isotope dilution/alpha ray spectrometry. Extraction chromatography, anion exchange chromatography and solvent extraction were applied to the analysis. The analytical results of Th and U in JMn-1 were in agreement with the literature values determined by ICP-MS (inductively coupled plasma mass spectrometry) or INAA (instrumental neutron activation analysis). It was found that the concentration of 210Pb in JMn-1 was higher than that in other certified reference materials for environmental radioactivity. JMn-1 proved to be useful for quality control sample in the analysis of environmental radioactivity.

Keywords : standard rock sample; certified reference material; JMn-1; alpha ray spectrometry; environmental radioactivity.


Dissolution procedures for several vanadium alloys in inductively coupled plasma-optical emission spectrometry

Yûetsu Danzaki1 and Kazuaki Wagatsuma1

1 Institute for Materials Research, Tohoku University, 2-1-1, Katahira, Aoba-ku, Sendai-shi, Miyagi 980-8577

(Received 6 May 2003, Accepted 5 August 2003)

Proper dissolution methods for various V alloys were examined for elemental determination in inductively coupled plasma-optical emission spectrometry (ICP-OES). Several kinds of V alloys were developed for various purposes. Among them, alloys co-containing Ti, Nb, and Ta are being employed as structural materials. Hydrolytic reactions of these elements occur in aqueous solution easily; therefore, an agent should be added to prevent their hydrolysis. Hydrogen peroxide is an effective agent against hydrolysis. However, when H2O2 is added to solutions containing V, it accelerates the decomposition of H2O2 and then O2 gas generates, which leads to poor precision of the analytical results in ICP-OES. Therefore, a proper dissolution method for each V alloy should be developed without usage of H2O2. V-Cr, V-Fe and V-Mo alloys were dissolved in a HNO3-HCl solution. V-Zr, Ti-Al-V and Ni-Ti-V alloys were finished as a H2SO4 solution after dissolving in HNO3-HF and fuming with H2SO4. A V-Nb alloy was added to a H2SO4-tartaric acid solution after dissolving in HNO3-HF and fuming with H2SO4. A Nb-Al-V alloy was dissolved in NO3-HF at room temperature. Nb-Cr-V alloys were finished as a H2SO4-HF solution after dissolving in HNO3-HCl-HF, followed by fuming with H2SO4 and adding HF.

Keywords : V alloy; dissolution method; ICP-OES.


Short Communication

Control of the elution order of enantiomers by light irradiation using azobenzene-modified chiral stationary phases in micro liquid chromatography

Tamiyuki Igari1, Tatsuro Nakagama1, Katsumi Uchiyama1 and Toshiyuki Hobo1

1 Development of Applied Chemistry, Graduated School of Engineering, Tokyo Metropolitan University, 1-1, Minamiosawa, Hachioji, Tokyo 192-0397

(Received 18 August 2003, Accepted 25 August 2003)

In micro liquid chromatography, a method for the reversible control of the elution order of enantiomers by light irradiation was developed. Two photo-responsive chiral stationary phases (CSP(1) and CSP(2)) with an azobenzene moiety were prepared using D- and L-valine, respectively. The prepared stationary phases were continuously packed into a UV-permeable polymer-coated fused-silica capillary tubing (100 µm, i.d.) with 20 cm of length, respectively, and used as a micro column. When 3,5-dinitrobenzoyl-D,L-leucine isopropyl ester and 3,5-dinitrobenzoyl-D,L- alanine methyl ester were used as test samples, the samples were eluted in the order D-form and L-form, after UV light was irradiated to only the part of CSP(1) in the column. Continuously, when UV light was irradiated to the part of CSP(2) after visible light was irradiated to the CSP(1), the elution order became L-form and D-form. It could be seen that a reversible change in the retention order was caused by the reduction of the enantio-selectivity of the stationary phase by UV light irradiation.

Keywords : enantiomer separation; HPLC micro column; control of elution order; photo-responsive stationary phase.


Digests of Doctoral Dissertation

Formation and aggregation of palladium(II)-pyridylazo complex at liquid-liquid interface

Akira Ohashi

Department of Environmental Sciences, Faculty of Science, Ibaraki University, 12-1-1, Bunkyo, Mito-shi, Ibaraki 310-8512

(Awarded by Osaka University dated March 25, 2002)

The complexation and aggregation reactions of a palladium(II)-pyridylazo complex (PdL) at the liquid-liquid interface were investigated by means of conventional and new methods, and new-type isomer recognizing reactions of diazine derivatives with PdL by complexation and aggregation at the liquid-liquid interface were proposed in this thesis. Their isomer recognizing reactions were not observed in a homogeneous system, and the specificity of the liquid-liquid interface as a reaction field has been revealed. These results developed a new function of the liquid-liquid interface as an analytical and synthetic field. Moreover, a new microscopic method, named centrifugal liquid membrane-resonance Raman microprobe spectroscopy (CLM-RRMS), was proposed, and its advantage for measuring interfacial species was revealed. This method permitted a selective observation of the Raman spectra for the interface and bulk phases in the CLM system and time-resolved measurements of the interfacial reaction by resonance Raman scattering for the first time. The combination of the new method and the conventional method, such as the CLM method and the high-speed stirring method, allowed us to obtain much structural information about PdL adsorbed at the liquid-liquid interface and to understand the property of the liquid-liquid interface.

(Received July 14, 2003)

Keywords : liquid-liquid interface; aggregation; molecular recognition; palladium(II)-2-(5-bromo-2-pyridylazo)-5-diethylaminophenol complex; centrifugal liquid membrane method; resonance Raman spectroscopy.


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