Vol. 4 8, No. 8
August, 1999
Katsumi Uchiyama*
*Department of Applied Chemistry, Graduate School of Engineering, Tokyo Metropolitan University, 1-1, Minamiohsawa, Hachioji-shi, Tokyo 192-0397
(Received 9 April 1999)Some applications and characteristics of photothermal spectroscopy, including photoacoustic spectroscopy, photothermal deflection spectroscopy and thermal-lens spectroscopy, to planar chromatography (thin-layer chromatography, slab gel electrophoresis) were reviewed. At first, some examples of photoacoustic cells were described. Then, applicability and sensitivities for the method were described. The method was applied to the quantitative and qualitative analysis of samples developed on a thin-layer chromatography (TLC) plate. The mapping methods using photothermal spectroscopy were described. These methods utilized light-scanning photoacoustic densitometry, photothermal spectrometry and photoacoustic densitometry by fast laser-beam scanning. Mapping techniques utilizing photothermal spectroscopy were successfully applied to samples developed on a TLC plate, of which the light-dispersing characteristics made a precise measurement difficult. The mapping techniques for proteins separated on polyacrylamide gels were also described in detail. The thermal diffusivity of dried polyacrylamide gel (2.0×10-3 cm2/s) made the photoacoustic signal small. Sensitive determinations were possible when sample proteins in polyacrylamide gels were transferred to nitrocellulose sheets or when the samples were electrophoresed in very thin polyacrylamide gels.
Keywords : photoacoustic spectrometry; thin-layer chromatography; gel electrophoresis; laser; scanning; densitometry; imaging.
Hiroshi Shiigi, Masaharu Nakayama and Kotaro Ogura*
*Department of Applied Chemistry, Faculty of Engineering, Yamaguchi University, 2557, Tokiwadai, Ube-shi, Yamaguchi 755-8611
(Received 20 January 1999, Accepted 23 April 1999)A composite film was prepared from soluble polyaniline (PAn) and poly (vinyl alcohol) (PVA) and its application as a humidity sensor was investigated. Soluble PAn was made by the chemical polymerization of aniline with ammonium peroxydisulfate in a p-toluene sulphonic acid aqueous solution. The electrical conductivity of the PAn/PVA composite film was proportional to the atmospheric humidity without any accompanying hysteresis, extending from 3×10-5 Scm-1 to 0.2 Scm-1 upon a change in humidity from 0 to 100%RH. The effects of coexisting gases such as NH3, HCl, MeOH, EtOH, tetrahydrofuran (THF) and hexane on the humidity response of the composite film were examined, and the humidity response was not found to be affected by the coexisting gases, of which the concentrations were less than 4000 ppm (HCl), 15000 (NH3), 25000 (MeOH), 18000 (EtOH), 10000 (THF) and 7500 (hexane), respectively. This means that the composite film can be applied as a humidity sensor in a common environment without being affected by these coexisting gases.
Keywords : soluble polyaniline; composite film; humidity sensor; coexisting gases; electrical conductivity.
Masaru Mitsushio* and Satsuo Kamata**
*Department of Applied Chemical Engineering, Graduate School of Engineering, Kagoshima University, 1-21-40, Korimoto, Kagoshima 890-0065
**Department of Applied Chemical Enginnering, Faculty of Engineering, Kagoshima University, 1-21-40, Korimoto, Kagoshima 890-0065
A sensor system using an optical fiber was developed and its response was tested to ethanol and ethylene glycol in water. The clad was removed from the fiber with sulfuric acid and its fiber core was coated with a gold film. The gold-coated unclad fiber responded rapidly and sensitively to the examined reagents, as compared to an unmodified unclad fiber. The calibration graph of transmittance vs. concentration showed a good relation in the range of 0~80% for ethanol and 0~40% for ethylene glycol. The detection limit was 0.5%. It was found that these alcohols could be determined in real time. The alcohol content in liquors (Shochu), which was determined directly by this method, showed 25.2 v/v%, very mean to the value (25 v/v%) indicated on the label of the Shochu bottle.
Keywords : optical fiber; evanescent wave; laser; ethanol; ethylene glycol; liquors.
Satoshi Nomura, Shuji Takamatsu, Motoi Nakao*, Yan-Gou Yang, Chihiro Inoue and Tadashi Chida**
*R&D Center, Horiba Ltd., 2, Kisshoinmiyanohigashimachi, Minami-ku, Kyoto 601-8510
**Department of Geoscience and Technology, Graduate School of Engineering, Tohoku University, Aoba, Aramaki, Aoba-ku, Sendai 980-8579
(Received 10 March 1999, Accepted 11 May 1999)We propose the application of pH-imaging technology to the observation of proton transport in porous media. A flat pH-imaging sensor based on the electrochemical-semiconductor principle was employed for imaging. Porous media were formed by packing particles with a few hundred-micrometer diameter such as silica sands, glass-beads and ion- exchange resins. These particles were packed on the pH-imaging sensor, respectively, followed by the addition of an acid solution from the top surface of the layer. The pH distribution formed on the interface between the sensor and the layer was repeatedly imaged with a 3 min time resolution. The dependence of proton transport on the particle type and size was clearly imaged and quantitatively evaluated. The proposed method was confirmed to be useful for understanding mass transport in porous media, thus enabling contribution to fundamental research involving the transport of chemicals in soil/aquifer/reservoir, such as bioremediation and microbial-enhanced oil recovery (Microbial EOR).
Keywords : pH-imaging; proton diffusion; distribution; porous media.
Takashi Goto and Hiroki Tange*
*Department of Industrial Chemistry, College of Engineering, Nihon University, 1, Nakagawara, Tokusada, Tamura, Koriyama-shi, Fukushima 963-8642
(Received 1 March 1999, Accepted 23 April 1999)The separation and preconcentration of trace tin from seawater for a graphite- furnace AAS (GF-AAS) determination was studied using silica gel loaded with Pyrocatechol Violet (PV)/trioctylmethylammonium chloride (Capriquat). The proposed adsorbent was prepared as follows ; ten grams of silica gel were shaken into 50 ml of 5% Capriquat-xylen solution and 20 ml of 0.05% PV solution for 30 min. A sample solution of 100~1200 ml containing Sn was adjusted to pH 5. The solution was then passed through 0.5 g of PV/Capriquat-loaded in silica gel on the column, eluted with 10 ml of 1.0 M hydrochloric acid, and then deteminated by GF-AAS. In this method, over 98% of Sn was adsorbed at about pH 5. The proposed method has been applied to the determination of Sn in seawater samples.
Keywords : tin; PV/Capriquat loaded silica gel; graphite furnace AAS; seawater.
Toshiyuki Mitsui and Hiroyuki Sakakibara*
*Criminal Investigation Laboratory, Aichi Police H.Q., 2-1-1, Sannomaru, Naka-ku, Nagoya 460-8502
(Received 25 February 1999, Accepted 26 April 1999)Thirteen samples of office cinnabar ink made in Japan were measured for the differential determination by microscope photometry. The method was as follows. Each sample was magnified by 50 times and the absorbance values were measured from 380 to 760 nm in 5 nm intervals by a microscope photometer. Each absorbance in a sample was divided by the absorbance at 380 nm. The obtained data of each sample were used for a calculation in a multivariate analysis, such as a cluster analysis, a principal-component analysis, KNN, and SIMCA. A classification of 13 different office cinnabar inks could be made using the cluster analysis, KNN and SIMCA.
Keywords : cinnabar ink; microscope photometer; multivariate analysis such as cluster analysis; principal component analysis; KNN and SIMCA.
Kenji Fujiwara, Kazuo Murata, Masanori Inada* and Taketoshi Nakahara**
*CRT Development Center, Electron Tube Company, Matsushita Electronics Corporation, 1-1, Saiwai-cho, Takatsuki-shi, Osaka 569-1193
**Department of Applied Chemistry, Osaka Prefecture University, 1-1, Gakuen-cho, Sakai-shi, Osaka 599-8531
PTFE(polytetrafluoroethylene) and PFA(perfluoroalkoxy) have been widely used in the semiconductor industry due to their chemical inertness, thermal stability and low impurity concentration. We therefore need to find a technique to determine an ultratrace amount of metals in fluorocarbon resin, which is a raw material of PTFE and PFA. We developed a new procedure in which a fluorocarbon resin is placed on a silicon(Si) wafer set in a combustion chamber made of quartz and locate the chamber in an electric furnace. We decomposed the resin at 550°C in air and etched about 0.2 µm of the surface layer of the wafer using an acid mixture of HF and HNO3 (1/20 by volume), and determined Na, Al, K, Ca, Cr, Fe, Ni, Cu and Zn in the etching solution using GFAAS with low blank concentrations of 0.05, 0.4, 0.07, 0.2, 0.2, 0.3, 0.3, 0.2 and 0.9 ng g-1, respectively. We confirmed that this technique gave a low blank concentration and was a rapid and accurate analytical method for fluorocarbon resin.
Keywords : fluorocarbon resin; silicon wafer; combustion chamber; graphite furnace AAS; ultratrace metals.
Kunihiro Watanabe, Norio Omae and Masayuki Itagaki*
*Department of Industrial Chemistry, Faculty of Science and Technology, Science University of Tokyo, 2641, Yamazaki, Noda-shi, Chiba 278-8510
(Received 2 March 1999, Accepted 8 April 1999)The enhancing effect of 3,5-dichlorophenol on the fluorescence intensities of the Al(III)-8-hydroxyquinoline complex in a surfactant micelle was investigated. To examine the enhancement mechanism, the fluorescence properties of the Al(III)-8-hydroxyquinoline complex in surfactant micelle containing 3,5-dichlorophenol were measured by a fluorescence-lifetime instrument. The radiationless transition- rate constant (kq) decreased compared with kq in a surfactant solution without 3,5-dichlorophenol. This result indicated that Al(III)-8-hydroxyquinoline complex can be protected from the bulk water as a quencher by using 3,5-dichlorophenol through hydrogen bonding. A non-ionic surfactant micelle was separated as an organic phase from an aqueous phase above the cloud point. Therefore, Triton X-100 of the non-ionic surfactant was used as an extraction solvent for the Al(III)-8-hydroxyquinoline complex in the presence of 3,5-dichlorophenol. As a result, dichlorophenol enhanced the fluorescence intensity of the Al(III)-8-hydroxyquinoline complex in the Triton X-100 phase. The relationship between the 3,5-dichlorophenol concentration and the fluorescence intensities of the Al(III)-8-hydroxyquinoline complex in the surfactant phase was studied.
Keywords : 3,5-dichlorophenol; fluorescence properties; surfactant; cloud point.
Jun Kawai* and Hideyuki Takahashi**
*Department of Materials Science and Engineering, Kyoto University, Sakyo-ku, Kyoto 606-8501
**JEOL Ltd., 3-1-2, Musashino, Akishima-shi, Tokyo 196-8558
Keywords : extended X-ray emission fine structure; extended X-ray absorption fine structure; electron probe X-ray microanalyzer; magnesium oxide.
Hisashi Kambe, Toshimichi Shibue* and Izumi Hirasawa**
*Materials Characterization Central Laboratory, School of Science and Engineering, Waseda University, 3-4-1, Okubo Shinjuku-ku Tokyo 169-8555
**Department of Applied Chemistry, School of Science and Engineering, Waseda University, 3-4-1, Okubo Shinjuku-ku Tokyo 169-8555
The applicability of tandem mass spectrometry to the quality analysis of metal-surface protect surfactants without any pretreatment or purification of the sample solution was investigated. Three typical spectra were constructed and verified by FAB CID-MS/MS using sodium n-dodecylsulfate (anionic surfactant), tetradecyl dimethylbenzylammonium chloride (cationic surfactant) and heptaethylene glycol mono-n-dodecyl ether (nonionic surfactant) as a model. The FAB CID-MS/MS spectra of metal-surface protect surfactants provided useful structural information that analyte surfactants have a polyoxyethylene structure, which has been identified as a nonionic surfactant. The authors concluded that FAB CID-MS/MS will be a good analytical method for direct quality analysis without any pretreatment or purification of the metal-surface protect surfactant for industrial use.
Keywords : mass spectrometry; surfactant; tandem mass spectrometry; fast atom bombardment; charge-remote fragmentation.
Yasushi Ishihama
Analytical Research Laboratories, Eisai Co., Ltd., 5-1-3, Tokodai, Tsukuba, Ibaraki 300-2635
(Awarded by Kyoto University dated May 25, 1998)Capillary electrophoresis (CE) was used to evaluate drug hydrophobicity, dissociation constants (pKa), and protein unfolding. In one study, the hydrophobicity of solutes was measured by microemulsion electrokinetic chromatography (MEEKC). The logarithm of the capacity factors was highly correlated with the logarithm of the octanol/water partition coefficients (log Pow). The reproducibility was drastically improved by using the migration index (MI). MI provided a better correlation with some bioactivites than did other hydrophobicity parameters, such as log Pow. In a second study, a general equation for use in calculating pKas from solute mobilities observed at different pHs was derived to be suitable for multivalent compounds with close pKas. This method was useful for slightly soluble compounds and compounds containing some impurities or that decompose easily. In a third study, the thermodynamic parameters of the thermally-induced unfolding of proteins were determined by CE using an in-column incubation method. Although the apparent transition temperatures by CE were generally consistent with those obtained by far-UV CD, these two methods had different detection selectivities for changes in the protein structures. These nanoscale methods have some advantages, such as high speed and high reproducibility, and should be applicable in various fields.
(Received April 8, 1999)Keywords capillary electrophoresis; hydrophobicity; dissociation constant; protein unfolding.
Fumiaki Yokota
Industrial Research Institute, Aichi Prefectural Government, Nishi-Shinwari,Hitotsugi-cho, Kariya-shi, Aichi 448-0003
(Awarded by Nagoya University dated March 3, 1998)New uses of non-oxide advanced ceramics have been expected because of their attractive properties, such as high melting point, hardness and high electric conductivity. Because their properties are markedly affected by impurities (some metals, carbon), the determination of metal impurities is important in their characterizations. In the present thesis, the determination of metal impurities in TaC, TaN, TiB2, TiSi2, VC, ZrB2 and ZrSi2 powder samples by inductively coupled plasma atomic emission spectrometry (ICP-AES) is presented. For ICP-AES, the powder samples must be digested into solution. Considering the contamination from reagents, decomposition vessels and the decomposition procedure, itself, sample-decomposition procedures with inorganic acids were carried out under high pressure in a PTFE pressure vessel. In a series of decomposition studies, several new findings concerning the acid-resistance of the ceramics mentioned above were obtained. Although it has been reported that, for instance, TaN was insoluble in all acids, TaN could be dissolved in a mixture of hydrofluoric acid and hydrogen peroxide solution. The matrix effects on the background levels and the emission intensities of the impurity elements in the ICP-AES measurement were compensated by matrix-matched standard solutions for a calibration. For most elements, the values obtained by the proposed method were in good agreement with those obtained by atomic-absorption spectrometry. These results indicate that the proposed methods discussed here are useful to determine metal impurities in ceramic powders and that they will contribute to the development of new applications of non-oxide advanced ceramics.
(Received April 21, 1999)Keywords ICP-AES; impurity determination; non-oxide advanced ceramics; acid decomposition under high pressure.
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