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Volume 54, Issue 1
Displaying 1-11 of 11 articles from this issue
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Review
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Takeshi HASEGAWA, Yukihiro OZAKI2005 Volume 54 Issue 1 Pages 1-26
Published: 2005
Released on J-STAGE: April 08, 2005
JOURNAL FREE ACCESSA recent trend of chemometrics for spectral analysis is summarized. A fundamental concept for the analysis of spectra using chemometrics by considering the spectra as multivariate data is presented, followed by the introduction of a quantitative analysis of spectra, classification of spectra, pretreatment of spectra, and spectral decomposition techniques using the latest examples of chemometric studies.
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Account
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Tetsuo OKADA, Makoto HARADA2005 Volume 54 Issue 1 Pages 27-41
Published: 2005
Released on J-STAGE: April 08, 2005
JOURNAL FREE ACCESSThis paper reviews the electrostatic and solvation effects, both of which play decisive roles in separation and recognition of ions. Charged interfaces are often utilized for ionic separation and recognition; ion-exchange chromatography, micellar partition, ion sensors, and solvent extraction are typical examples. Usual stoichiometric rules, which assume two discrete phases and the electroneutrality in both phases, do not apply to such systems where electrostatic energies dominate the entire interaction, because the electrostatic force is exerted beyond a long distance. We have evaluated the results of chromatographic separation of ions with models derived from electrostatic theories, and have revealed various phenomena that were not found by the conventional stoichiometric models. Considerations based on the electrostatic models strongly imply important involvements of ionic solvation in the determination of separation selectivity. X-ray absorption fine structure (XAFS) has thus been applied to elucidate the local solvation structures of ions at separation interfaces. XAFS has very high elemental selectivity, is hardly subject to the interference from matrices, and provides structural data for noncrystalline materials. The local structures of counteranions in anion-exchange resins have been, for example, studied in various solvents, suggesting that tight ion-associations are formed between the ion-exchange groups and halide anions in aprotic solvents, while they are partly dissociated from the ion-exchange sites by complete solvation in water and methanol. In addition, the total reflection of the incident X-ray at the surface of an aqueous solution allows us to study XAFS of ions attracted by surface monolayers. Some results obtained with this novel method are also discussed.
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Research Paper
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Takashi MIYAWAKI, Ayato KAWASHIMA, Katsuhisa HONDA2005 Volume 54 Issue 1 Pages 43-49
Published: 2005
Released on J-STAGE: April 08, 2005
JOURNAL FREE ACCESSThe effect of water as an entrainer was studied on supercritical carbon dioxide extraction (SCE-CO2) of Polychlorinated dibenzo-p-dioxins/polychlorinated dibenzofurans (PCDD/DFs) in paddy soil. Using water as an entrainer elevated the extraction efficiency of PCDD/DFs, and it’s optimal extraction condition was as follows: a water flow velocity of 0.04 ml/min (2% versus CO2 flow velocity); 30∼40 MPa, 130∼190°C; 50 min dynamic SCE-CO2. The extraction efficiency of PCDD/DFs by 2% water entrainer was almost the same as those by 10% toluene- and 5% methanol-entrainers, and corresponded to about 80% of those by the conventional method (Soxhlet extraction). These results indicate that SCE-CO2 with water as an entrainer is rapid and organic-solvent less technique for the extraction of PCDD/DFs in soils.
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Satoshi NISHIMURA, Takanori INOUE, Yoshiaki KURAUCHI, Kazuya OHGA2005 Volume 54 Issue 1 Pages 51-56
Published: 2005
Released on J-STAGE: April 08, 2005
JOURNAL FREE ACCESSChanges in the color of pH indicators (Methyl Orange, Methyl Red, Thymol Blue, Phenol Red, Phenolphthalein and Alizarin Yellow) were observed when polyvinylpyrrolidone films containing each of these six pH indecators were exposed to methanol and typical odor components of citrus fruits. Color images of the polymer films obtained with a scanner were separated into red, green and blue components, and then the three components were converted into gray levels, integers from 0 to 255. Differences between the gray levels before and after exposure to the sample gases were characteristic of each of the gases, and showed that Alizarin Yellow/polymer film exposed to linalyl acetate and linalool gave large color changes, as the radar plots of the differences distinctly illustrated. An optical fiber having the Alizarin Yellow/polymer film at the cladding part and a thin gold film on an end surface was used as a sensing element; a decrease in the signal intensity of reflected halogen-lamp light from the fiber was observed at 635 nm when the fiber was exposed to linalyl acetate. A polymer film of 9.00 μm in thickness gave a significant decrease in the intensity; the response reached a steady state in 20 min.
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Haruo HONMA2005 Volume 54 Issue 1 Pages 57-64
Published: 2005
Released on J-STAGE: April 08, 2005
JOURNAL FREE ACCESSA procedure for a quick determination of the amount of the oxygen element present by means of contact thermal decomposition is as follows. Approximately 10 ml of carbon black is filled into a molybdenum cylindrical crucible developed by us. The crucible is heated to 1300°C, and a sample contained in a silver capsule is dropped into it for instantaneous thermal decomposition, by which the oxygen element is reduced to carbon monoxide. The principle of the method is that the carbon monoxide is oxidized to carbon dioxide at 650°C, and the amount of the resulting carbon dioxide can be determined using an infrared detector. The method of determination has been established by examining in detail the fundamental aspects listed below: 1) fabrication of prototypes of various instruments and evaluations of their functions, 2) adjustment of the reagent and apparatus used for the determination, 3) determination of a reference value for a blank test value and its behavior, 4) correction for obtaining a linear correlation between the signals detected by an infrared detector and to component concentration, 5) to contact thermal decomposition temperature, 6) a comparison of to effects of contact and no-contact thermal decompositions, 7) an examination of to oxidation condition under low temperature for carbon monoxide and 8) a measurement of to time required for a determination. In this study, the amounts of oxygen contained in several standard samples were determined in order to evaluate the accuracies of the obtained based values on the statistics of the determined values.
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Technical Paper
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Yasuhiro TERAUCHI, Tetsuya KAWABE, Nobuo NAKANO, Yoshio SUZUKI, Kouji ...2005 Volume 54 Issue 1 Pages 65-70
Published: 2005
Released on J-STAGE: April 08, 2005
JOURNAL FREE ACCESSA portable formaldehyde gas monitor was developed and applied to measurements of the workplace environment using a sensitive and selective tablet for formaldehyde. It is based on a color change of the tablet by a reaction with formaldehyde. A tablet impregnated with a processing solution containing KD-XA01, phosphate buffer solution in methanol was found to be a highly sensitive and selective for the detection of formaldehyde. When a sample including formaldehyde was exposed to the tablet, the surface color of the tablet changed from white to yellow. The degree of the color change was proportional to the concentration of formaldehyde at a constant sampling time and flow rate, which was recorded by measuring the relative intensity of reflecting light at 400 nm. The tablet was used to detect 0.3 ppm of formaldehyde, which was set by ACGIH, with a sampling time of 3 min and a flow rate of 250 ml/min. Reproducibility tests showed that the relative standard deviation of the response (n = 10) was 2.1% for 0.3 ppm of formaldehyde. This monitoring method is simple, specific, and capable of unattended operation, and is recommended for the workplace environment.
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Note
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Hideaki KINOSHITA2005 Volume 54 Issue 1 Pages 71-74
Published: 2005
Released on J-STAGE: April 08, 2005
JOURNAL FREE ACCESSThe anodic steady-state current by a sulfhydryl compound in concentrations about 10 μM at a dialysis membrane covered phthalocyanine-embedded carbon paste electrode (mCoPCPE) completely vanished after the addition of N -ethylmaleimide (NEM) in double concentrations of the sulfhydryl compounds. The concentrations of reduced glutathione (GSH) in whole blood and serum were determined by measuring the current decrease at 150 mV after the addition of NEM in blood solutions of pH 6.8. This method has the advantage of eliminating the procedures for deproteinization. The correlation coefficients between the GSH concentration determined in this method and those by a spectrometric measurement were 0.98 and 0.90 for 10 whole blood and 15 serum samples, respectively
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Hiroyuki NODA, Tsuneyoshi GOTO, Hiroaki OHYA, Hitoshi KAMADA2005 Volume 54 Issue 1 Pages 75-78
Published: 2005
Released on J-STAGE: April 08, 2005
JOURNAL FREE ACCESSHighly accurate sensing for a temporal change in the freshness of brown rice was investigated using a chemiluminescence measurement. The experimental setup was composed of a dark box, a highly sensitive cooled CCD camera (HAMAMATSU, C4880), and a personal computer for data processing. The chemiluminescence intensity was estimated by using a photon counter (HAMAMATSU, C8801). Some pieces of brown rice were placed in the chemiluminescence measurement system. Two kinds of rice, such as new and old ones (stored at one year), were used for chemiluminescence measurements. The addition of 2-methoxyphenol, which is a substrate of peroxidase (POD), led to a decrease in the chemiluminescence intensity of brown rice. Therefore, the luminescence observed may have originated from the POD in brown rice. The chemiluminescence intensity of new rice was fifty-times larger than that of old rice. An increase in the storing period of brown rice at room temperature led to an extreme decrease in the chemiluminescence intensity. Further, the mixture of old and new rice could be distinguished by chemiluminescence imaging. Thus, the chemiluminescence measurement will be a useful technique to evaluate temporal changes in the freshness of brown rice.
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Naomichi FUKUDA, Michiko YONEMITSU2005 Volume 54 Issue 1 Pages 79-82
Published: 2005
Released on J-STAGE: April 08, 2005
JOURNAL FREE ACCESSBerberine and palmatine are isoquinoline alkaloids contained in “oubaku”, Phellodendri Cortex, and their structures are similar. The Rf values of TLC and the retention times (HPLC) of these compounds are close. Their complete separation is difficult; a small quantity of palmatine chloride exists even in a commercial berberine chloride. Some crystals exist in the Student practice, from gel-type crystals (small needles) to big needles according to the volume of water. These phenomena suggest that a possibility exist to purify berberine chloride only by recrystallization. We recrystallized 3 times crude berberine (10 g, gained from the Student practice) from 140 ml of water per 1 g, and separated pure needles (neally 100%, 2.31 g) which were checked with HPLC.
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Analytical Report
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Koji MATSUSHITA, Hiroyuki SEKIGUCHI, Yasuo SETO2005 Volume 54 Issue 1 Pages 83-88
Published: 2005
Released on J-STAGE: April 08, 2005
JOURNAL FREE ACCESSThe detection performance of a portable surface acoustic wave sensor array chemical agent detector (JCAD, BAE Systems) was investigated with nerve gases, blister agents, and blood agents. The vapors of sarin, soman, tabun and lewisite 1 (low level) were recognized as “NERV (nerve agent)” after about 10 sec of sampling, and the detection limits were about 30, 50, 100 and 300 mg/m3, respectively. The vapors of mustard gas and lewisite 1 (high level) were recognized as “BL (blister agent)” after about 10 sec sampling, and the detection limit for mustard gas was about 40 mg/m3. The gases of hydrogen cyanide and cyanogen chloride were recognized as “BLOD (blood agent)” after about 2 min sampling, and the detection limits were about 30 and 1000 mg/m3, respectively. Many solvents, such as methanol, dichloromethane and ammonia, were also recognized as chemical-warfare agents.
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Kazuyuki TSUCHIYA, Yuzo TAMARI2005 Volume 54 Issue 1 Pages 89-94
Published: 2005
Released on J-STAGE: April 08, 2005
JOURNAL FREE ACCESSThe rubidium content of infant formulas was determined by flame photometry using the atomic absorption spectrophotometer (AAS) with air-acetylene flame. In this work, the optimum instrumental conditions for rubidium analysis were determined: the burner height of AAS, the acetylene pressure, the hydrochloric acid concentration as a measuring solution and so on. The effects of coexisting ions expected from matrix components of infant formulas were tested; the results showed no interferences of Na+, Ca2+, Mg2+, PO43− (∼250 μg/ml) and K+ (∼25 μg/ml). In addition, a variation of the sample amount (0.1∼1 g) for the analysis did not interfere with the determination of the rubidium content of the sample. Rubidium was determined as follows: A sample (0.3 g) in a beaker (50 ml volume) was decomposed by heating with a nitric-perchloric acid mixture on a hot-plate; the solution was then diluted to 100 ml with water after the addition of 2 ml of 6 mol/l hydrochloric acid. Standard rubidium was recovered to be 100 ± 0.9 (n = 20) from an infant formula sample. This method was applied to 24 infant formula samples, resulting in the fact that there was a significant difference in the rubidium content between 10.7 ± 2.9 μg/g (n = 14) in follow-up formulas and 5.35 ± 1.71 μg/g (n = 10) in young infant formulas (p<0.05).
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