Zn(PTA)2·phen(o)+2H2O(o), Vol. 50 No. 7
July, 2001
Shinya Matsu-ura, Yuji Yamauchi, Hidenobu Ohmori and Hatsuo Maeda*
*Graduate School of Pharmaceutical Sciences, Osaka University, Yamada-Oka, Suita-shi, Osaka 565-0871
(Received 5 March 2001, Accepted 12 April 2001)Recently, we found that the perhydrolysis of acetyl resorufin (ACR) to fluorescent resorufin can be used as a novel indicator reaction for a fluorometric analysis of glucose coupled with glucose oxidase (GOD). In the present study, the applicability of this indicator reaction in fluorometric determination of blood glucose was explored. A fluorometric method with GOD and ACR (GOD/ACR method) was successfully capitalized in a glucose determination of plasma subjected to a deproteinization procedure with ZnSO4-Ba(OH)2, provided that a GOD solution was prepared by a 10 mM phosphate buffer (pH 7.4). The use of the GOD solution worked well not only to prevent the formation of a precipitation during the enzymatic reaction of a deproteinized glucose solution in the presence of ACR, but also to improve the sensitivity of the present fluorometry. The GOD/ACR method afforded a calibration curve over the range of glucose concentration between 0 and 250 mg/100 ml, and allowed the determination of blood glucose with high repeatability, as shown by less than 2% (n=5) of the relative standard deviations. The obtained glucose levels for plasma were slightly higher than those measured by Trinder's method. The results concerning not only the assessment of effects of added ascorbic acid, but also the recovery tests suggest that the difference in the glucose levels determined by both methods comes from the low accuracy of Trinder's method in the presence of inhibitors, such as ascorbic acid. An excellent stability of ACR in CH3CN as well as the above results lead to the expectation that the GOD/ACR method will offer a reliable and accurate tool for the clinical analysis of glucose.
Keywords : perhydrolysis of acetyl resorufin; indicator reaction; fluorometric analysis of glucose; blood glucose; glucose oxidase.
Yasuhiro Gou*
*The Kumamotoshi Eastern Purification Center, 536, Akita, Akitsumachi, Kumamoto 861-2105
(Received 19 February 2001, Accepted 12 May 2001)A simple and rapid method was proposed for the spectrophotometric determination of total nitrogen in sewage, seawater and river-water samples. Water samples were taken into glass bottles with screw caps coated with teflon, and the bottles were then sealed with screw caps after addition of potassium peroxodisulfate; were heated at 120°C for 30 min. During heating, all nitrogen compounds were quantitatively oxidized into nitrate. The determination of the resulting nitrate was performed by measuring the absorbances at 380 nm after an oxime formation reaction with phenol. The proposed method was applied to the determination of total nitrogen in sewage, seawater and river water samples. The results correlated well to those determined by the UV method (JIS method) or a total nitorogen analyzer (JIS method). The proposed method has some advantages over other methods, since the amounts of total nitrogen can be semiquantitatively evaluated by a visual observation of developed yellow color.
Keywords : total nitrogen; phenol; sewage; spectrophotometry; nitrate.
Izuru Matsubayashi, Akiko Inagaki and Yuko Hasegawa*
*Department of Chemistry, Faculty of Science, Science University of Tokyo, 1-3, Kagurazaka, Shinjuku-ku, Tokyo 162-8601
(Received 9 April 2001, Accepted 20 May 2001)From the extraction data of zinc(II) with pivaloyltrifluoroacetone (1,1,1-trifluoro-5,5-dimethyl-2,4-hexanedion, PTA) and/or 1,10-phenanthroline (phen), the formation constants of Zn(PTA)2 adduct with phen (β1=[Zn(PTA)2·phen]o[Zn(PTA)2]o-1[phen]o-1) were determined in chloroform, carbon tetrachloride, and hexane. When the adduct formation constants were plotted against the concentration of water saturated into the organic solvents, a straight line having a slope of -2 was obtained. This suggests that the equilibrium of the adduct formation can be described as
Zn(PTA)2·2H2O(o)+phen(o)Zn(PTA)2·phen(o)+2H2O(o),
Keywords : zinc(II) chelate; synergistic extraction; 1,10-phenanthroline; adduct formation constants; water in organic solvents.
Kousaburo Ohashi, Nobuhiro Matsuta and Hisanori Imura*
*Department of Environmental Sciences, Faculty of Science, Ibaraki University, Mito 310-8521
(Received 27 April 2001, Accepted 29 May 2001)The synergisticextraction of zinc(II) and cadmium(II) with 5-(4-nitrophenylazo)-7-(4-ethyl-1-methyloctyl)-8-quinolinol (HNEQ) into 1,2-dichloroethane (DCE), chloroform and 1-octanol in both the absence and presence of tri-n-octylphosphine oxide (TOPO) as well as the mutual separation of these metal ions were investigated. Various equilibrium constants were determined. Upon the addition of TOPO on the Zn(II)-HNEQ and Cd(II)-HNEQ systems, the extraction percentage-pH curves shifted toward a more acidic region. The synergistic extraction constant for the Zn(II)-HNEQ-TOPO-DCE system, Kex,s (=[Zn(NEQ)2(TOPO)][H+]2[Zn(II)]-1[HNEQ]-2[TOPO]-1), was determined to be 10-0.43 at 25°C and I=0.1 M (H, Na)ClO4. The formation constant, βa,1 (=[Zn(NEQ)2(TOPO)]org[Zn(NEQ)2]-1org[TOPO]-1org), of the association complex in DCE was found to be 105.65 at 25°C. The addition of TOPO to Zn(II)-HNEQ-DCE system showed a larger synergistic effect than that to the Zn(II)-HNEQ-chloroform system. The separation efficiency of zinc(II) and cadmium(II) was enhanced upon the addition of TOPO and chloride ion using DCE as a solvent.
Keywords : synergistic extraction; zinc(II) and cadmium(II); 5-(4-nitrophenylazo)-7-(4-ethyl-1-methyloctyl)-8-quinolinol; tri-n-octylphosphine oxide.
Masaki Takaoka*, Yutaka Shimaoka**, Nobuo Takeda and Takeshi Fujiwara*
*Department of Environmental Engineering, Graduate School of Engineering, Kyoto University, Yoshidahon-machi, Sakyo-ku, Kyoto 606-8501
**Waste Management Division, Department of Environment, Aichi Prefectural Government, 3-1-2, Sannomaru, Naka-ku, Nagoya 460-8501
In order to understand the reaction in a continuous mercury analyzer with the dry-type reduction process, the surface of granular tin metal in a dry-type reduction process was characterized by X-ray photoelectron spectroscopy (XPS). First, the method for chlorinating the surface of tin metal was investigated. It was found that the surface of tin metal was more deeply chlorinated by impregnating with 1 mol/l hydrochloric acid for 2 hours than by passing 600 ppm hydrochloric acid gas through the reactor for the number of same hours. Subsequently, the change on the surface of granular tin metal by impregnating with 1 mol/l hydrochloric acid was observed in the case of passing air with mercury(II) chloride gas and moisture through the reactor. Tin(II) chloride on tin metal changed into tin(II, IV) oxide upon exposure to air or moisture. Depth profiles indicated that a tin(IV) oxide layer was formed on a tin(II) oxide layer. These results suggested that the reducibility of tin metal depended on the ratio of the chlorinated surface. As for the reaction on the surface of tin metal pre-coated with 1 mol/l hydrochloric acid, the resulting X-ray photoelectron spectra were in good agreement with the reaction estimated from the mass balance in the actual experiment.
Keywords : X-ray photoelectron spectroscopy; tin metal; continuous mercury analyzer; dry-type reduction process; tin(II) chloride.
Kunihiro Watanabe, Takuya Okada, Arkin Iburaim and Masayuki Itagaki*
*Department of Industrial Chemistry, Faculty of Science and Technology, Science University of Tokyo, 2641, Yamazaki, Noda-shi, Chiba 278-8510
(Received 27 November 2000, Accepted 22 April 2001)The adsorption of metal ions to the inner surface of a Teflon tube was investigated. A Teflon tube is used in flow analysis, such as in the catalytic method and the chemiluminescence method, as a reaction coil and as a means to transport solvents containing analyte, reagents and a pH buffer agent. A Teflon surface obtained by treating with an alkaline solution (2 M NaOH, 3 h) adsorbed metal ions in the flow solution. The species adsorbed on the inner surface of the Teflon tube interfered with the determination owing to an increase in the blank values. The adsorbed species were metal cations in an alkaline solution. The site of adsorption was presumed to be the anion site based on dissociation of the hydroxy group introduced by the substitution of fluorine. Therefore, a method for decreasing the adsorption sites was examined. As a result, the addition of magnesium(II) was effective to decrease the blank values. In the case of a catalytic analysis for manganese(II) with 2-hydroxy-1-(2-hydroxy-4-sulfo-1-naphthylazo-3-naphtoic acid, the reagent blank decreased down to the minimum value upon the addition of magnesium(II). The number of adsorption sites obtained with the determination of fluorine eliminated by an alkaline treatment agrees with the result (3.1×1012/cm2) calculated from saturated adsorbents.
Keywords : adsorption of metal ions; Teflon tube; effect of suppressor; site of adsorption.
Manabu Miyoshi, Kotaro Izumi, Ryuichi Yoshida and Chikakiyo Nagata*
*Department of Applied Chemistry, Faculty of Engineering, Shibaura Institute of Technology, 3-9-14, Shibaura, Minato-ku, Tokyo 108-8548
(Received 20 February 2001, Accepted 20 May 2001)The 1H- and 13C-NMR spectra of trimethyl(1-indenyl)germanium(IV) and dimethylbis(1-indenyl)germanium(IV) compounds were measured. Assignments of the chemical shifts for 1H and 13C in those compounds were obtained by means of hydrogen-hydrogen nuclear Overhauser effect spectroscopy (H-H NOESY), hydrogen-hydrogen correlation spectroscopy (H-H COSY) and carbon-hydrogen correlation spectroscopy (C-H COSY). The methyl proton and carbon signals for two stereoisomers (R,R and R,S) in the dimethylbis(1-indenyl)germanium(IV) compound were separated into three signals, with a relative signal intensity of 1:2:1; the other protons and carbons were separated, except for H1, H4, C5, C9, into two signals. These results were considered to show that the separated signals were caused by being magnetically nonequivalent in the two stereoisomers.
Keywords : methyl(1-indenyl)germanium(IV) compounds; 1H- and 13C-NMR chemical shifts.
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