Vol. 5 0, No. 1
January, 2 0 0 1
Totaro Imasaka*
*Faculty of Engineering, Kyushu University, 6-10-1, Hakozaki, Higashi-ku, Fukuoka 812-8581
(Received 18 August 2000)In supersonic jet spectrometry, a molecule is cooled to several K in the gas phase. By cooling the molecule, it becomes possible to observe a structured excitation or multiphoton ionization spectrum comprising sharp spectral lines. Further, it is also possible to measure a fluorescence spectrum or photo-ionization mass spectrum to identify the chemical species. Therefore, high spectral selectivity is provided in this approach. If necessary, it is possible to combine this method with synchronous scan luminescence spectrometry or a separation technique in order to improve the selectivity. On the other hand, this method allows single-molecule detection, in theory. Thus, supersonic jet spectrometry has both very high selectivity and sensitivity. Recently, an ultrasensitive technique is strongly required for dioxin analysis, and supersonic jet spectrometry is expected to be used for this purpose. However, dioxins consist of various type of compounds having different toxicities and, as a result, a method which is capable of differentiating these compounds is desirable. In addition, due to the very high toxicities of these compo unds, it is necessary to use a sensitive method as well for ultratrace analysis. For these reasons, supersonic jet spectrometry has been developed for successful use in dioxin analysis. The present status concerning the development of this method is also described in this report.
Keywords : supersonic jet spectrometry; multiphoton ionization; mass spectrometry; low temperature spectrometry; dioxin analysis; trace analysis.
Koichi Yamamoto* and Shoji Motomizu**
*Department of Materials Science, Yonago National College of Technology, 4448, Hikona-cho, Yonago-shi, Tottori 683-8502
**Department of Chemistry, Faculty of Science, Okayama University, 3-1-1, Tsushimanaka, Okayama 700-8530
The distribution behavior of ion associates of both monovalent and divalent metal-halogeno complex anions with various quaternary ammonium cations between the aqueous phase and several organic phases {1,2-dichloroethane, chloroform (CF), chlorobenzene (Cl-B), benzene (B), toluene (T) and carbon tetrachloride (CTC)} was examined, and the extraction constants (log Kex) were determined. The larger is the size of the ligand (Cl-<Br-<I-) and the coordination number, the greater is the ion associability. For the same coordination number, in general, the larger is the size of the metal ion, the greater is the ion associability. In general, the extractability of monovalent metal-halogeno complex anions is larger than that of divalent metal- halogeno complex anions. A linear relationship was obtained between log Kex and the number of carbon atoms in quaternary ammonium ion, and the contribution of a methylene group to the extraction constant (Δlog Kex/-CH2-) was found to be about 0.4~0.8. Among the ion associates examined, the order of the extractability of the extracting solvent was generally CTC<T<B<Cl-B<CF. Also, the order of the extractability of the ion associates for dihalogenocuprate(I), tetrahalogenoaurate(III) and tetrahalogenothallate(III) complex ions was as follows, respectively: CuCl2-<CuBr2-<CuI2-; AuCl4-<AuBr4-; TlCl4-<TlBr4-<TlI4-. The values of Δlog Kex between the complex anions were almost equal, even though the extracting solvents were changed. From these results, several extraction-spectrophotometric methods for the determination of metal based on the formation of an ion associate of metal-halogeno complex anion with hydrophobic cations were developed.
Keywords : liquid-liquid distribution; metal-halogeno complex anion; quaternary ammonium ion; ion association; solvent extraction.
Norio Teshima, Takuya Nobuta, Tadao Sakai* and Takuji Kawashima**
*Department of Applied Chemistry, Faculty of Engineering, Aichi Institute of Technology, 1247, Yachigusa, Yakusa-cho, Toyota-shi, Aichi 470-0392
**Laboratory of Analytical Chemistry, Department of Chemistry, University of Tsukuba, 1-1-1, Tennodai, Tsukuba-shi, Ibaraki 305-8571
A spectrophotometric method for the determination of cysteine using a copper(II)-catalyzed redox reaction is presented. The slow redox reaction of cysteine with iron(III) in the presence of 1,10-phenanthroline (phen) was catalyzed by copper(II), producing an iron(II)-phen complex (λmax=510 nm). Cysteine in the range 1×10-6~6×10-5 M can be determined by measuring the absorbance at 510 nm. The limit of detection (3σ) was 5×10-7 M, and the RSD was 0.4% for ten determinations of 1×10-5 M cysteine. Many other amino acids did not interfere with the cysteine determination, while other reducing and oxidizing substances, such as ascorbic acid, vanadium(IV) and chromium(VI), seriously interfered. The proposed method was successfully applied to the determination of cysteine in a permanent-wave solution.
Keywords : cysteine determination; spectrophotometric method; copper catalysis.
Kazuki Nanameki* and Satsuo Kamata**
*Scientific Investigation Research Laboratory, Kagoshima Prefecture Police H. Q., 10-1, Kamoike-shinmachi, Kagoshima 890-8566
**Department of Applied Chemistry and Chemical Engineering, Faculty of Engineering, Kagoshima University, 1-21-40, Korimoto, Kagoshima 890-0065
Phenobarbital could be determined by using a surface plasmon resonance (SPR) sensor with a thin gold metal immobilized monoclonal antibody. This method was based on a change in the refractive indexes on a gold surface by an immunoreaction. Phenobarbital in pure water was determined within 1 ppb~1000 ppm. Phenobarbital in urine could be determined by the standard addition method without any interference due to urine impurity. The detection limit of phenobarbital in human urine was 0.1 ppm in this method. A kinetic analysis gave the association constant (ka=2.7×10-6 M-1 s-1) and the dissociation constant (kd=8.6×10-4 s-1). This SPR method was sensitive and useful for crime investigations.
Keywords : phenobarbital; surface plasmon resonance sensor; monoclonal antibody; association constant; dissociation constant.
Mitsuyoshi Watanabe and Akira Narukawa*
*Materials Research Laboratory, Technical Center, NGK Insulators, Ltd., 2-56, Suda-cho, Mizuho-ku, Nagoya 467-8530
(Received 6 July 2000, Accepted 11 October 2000)In the proposed method, a powdered sample of 1 g in a PTFE sealed vessel was treated with 50 ml of hydrofluoric acid(1+9) at 70°C for 60 min. An undissolved residue obtained by filtration served for the determination of the inner oxygen(OI) by the inert-gas fusion method. The total oxygen (OT) in the untreated raw material powder was separately determined using the same fusion method. The surface oxygen (OS) content was calculated by subtracting the OI content from the OT content. The removed fraction of the oxygen-rich surface layer corresponded to 2 mass% of the raw material under the pretreating condition described above. The proposed method required 8 hours per sample with a relative standard deviation of 3.2%.
Keywords : silicon nitride; surface oxygen; acid dissolution; inert-gas fusion method.
Yuta Miyamae, Kenichi Yoshizawa and Junko Tsuchiya*
*Safety & Analytical Research Center, POLA Chemical Industries, Inc., 560, Kashio-cho, Totsuka-ku, Yokohama 244-0812
(Received 26 June 2000, Accepted 13 October 2000)Until recently, complicated techniques, such as the need for several pretreatments, have been required for the successful analysis of surfactants in mixtures. In particular, it has been found that the determination of an individual surfactant in a mixture of anion and amphoteric surfactants is very difficult. To address this problem, we established a new and simplified analytical method for mixtures of anion and amphoteric surfactants using liquid chromatography/mass spectrometry (LC/MS). This method does not requir a tedious pretreatment, and makes it possible to determine anionic and amphoteric surfactants individually in mixtures. It was confirmed that this method is applicable for the determination of anionic and amphoteric surfactants individually in several shampoos.
Keywords : LC/MS; anionic; amphoteric; surfactants; determination.
Yukari Kuwahara, Shin-ichi Izumoto and Hiroyuki Nishi*
*Analytical Chemistry Department, Product Technology Development Laboratory, Tanabe Seiyaku Co., Ltd., 3-16-89, Kashima, Yodogawa-ku, Osaka 532-5805
(Received 3 August 2000, accepted 11 October 2000)Enantiomer separation by capillary electrophoresis (CE) has attracted considerable attention among analytical chemists as a promising new technique, especially in the fields of pharmaceutical, clinical, and agrochemical sciences. Capillary zone electrophoresis (CZE) and electrokinetic chromatography (EKC), in which a chiral selector is simply added to the running buffer, are most widely used for enantiomer separation among various CE modes. Among the chiral selectors employed in CE, cyclodextrins (CDs) are the most successful in enantiomer separation. Especially charged CDs have been found to have a relatively wide enentioselectivity, compared with electrically neutral CDs. In this study, we investigated the enantiomer separation of drugs (28 compounds) by CE with sulfated CDs. This mode can be regarded as one type of EKC, because a charged pseudo-phase is added to the running buffer, and electrically neutral analytes can be separated by this mode. Three types of highly sulfated CDs (HS-CDs) were employed as chiral selectors. Compared with the usual sulfated β-CD (S-β-CD), the degree of substitution (DS) of the HS-CDs is high (average 12) and its distribution range is narrow. By using one of the HS-CDs as a chiral selector, 75% of the compounds tested were enantioseparated. The binding constants were also calculated from Lineweaver-Burk type plots. The values of the binding constants obtained for HS-CDs were 200~4000 M-1. These values were about ten-times larger than those in electrically neutral CDs. Therefore, the optimum concentration of the HS-CDs calculated from the equation derived from the Wren and Rowe model became very low. The electrostatic interaction will effectively contribute to the enantiorecognition of drugs. Furthermore, the migration order of some enantiomers (for example, denopamine and trimetoquinol) was reversed between the CE with HS-β-CD and that with HS-γ-CD.
Keywords : capillary electrophoresis; sulfated cyclodextrin; enantiomer separation; binding constant.
Satoshi Nishimura*
*Department of Applied Chemical Engineering, Graduate School of Engineering, Kagoshima University, 1-21-40, Korimoto, Kagoshima 890-0065
(Received 14 July 2000, Accepted 10 October 2000)A surface plasmon resonance (SPR) sensor was applied to a simple and speedy measurement of cholesterol. The lower detection limit was 5.6×10-4 mol/l for an ethanol solution of cholesterol. The measurable range for cholesterol almost equaled that of the concentration of cholesterol in serum without any pretreatment of the serum. There were differences between the data obtained by using a gold film and those by using an enzyme film, due to the presence of hydrogen peroxide produced by a reaction between the enzyme and cholesterol. The differences gave a linear plot in the cholesterol-concentration region of 2.0×10-3 to 2.0×10-2 mol/l, and reached a constant value in the region of 4.0×10-2 to 5.0×10-2 mol/l. The 3.0×10-3 mol/l ascorbic acid, which largely interfered with the spectroscopic measurement of cholesterol, did not interfere with this measurement of a 1.0×10-2 mol/l cholesterol/ethanol solution.
Keywords : surface plasmon resonance; cholesterol; enzymatic reaction.
Mamoru Miyada and Yoko Taniguchi*
*Chemistry section, Mie Industrial Reserch Institute, 5-5-45, Takachaya, Tsu-shi, Mie 514-0819
(Received 5 July 2000, Accepted 11 October 2000)This report proposes a modified spectrophotometric method with chrome azurol S for the determination of aluminium in portland cement. This method is simple and convienient compared to the conventional volumetric method(JIS R 5202), where the determination of iron and titanium in portland cement is needed before the detenmination of aluminium. In this method the values of aluminium are determined by a volumetric method with EDTA.In contrast to the JIS method, the modified spectrophotometric method with chrome azurol S does not require the predetermination of iron and titanium. The analytical results were in good agreement with those obtained by the JIS method.
Keywords : portland cement; aluminium; spectrophotometric method; chrome azurol S.
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