Vol. 51 No. 7
July, 2002
Katsunori Kohata
National Institute of Vegetable and Tea Science, 2769, Kanaya, Haibara, Shizuoka 428-8501
(Received 24 April 2002, Accepted 22 May 2002)The relationship between green tea research and analytical chemistry is discribed based on an example of our studies. For a quantitative evaluation of green tea, a sensory test is still mainly being used. However, an instrumental evaluation using analytical equipments, for example HPLC and capillary electrophoresis, has been developing. Especially, a near-infrared analysis (NIR) method has been practically and widely used concerning the distribution routes of green tea. FT-IR micro spectrometry, an ion meter and improved HPLC methods were used for analyses of unfavorable substances in green tea, which were a white powdery substance found on stored Tencha (Matcha is made of Tencha by grinding with a stone mortar), Na+ added as sodium glutamate to make tea tastier, NH4+ added as ammonium bicarbonate to keep tea leaves green, and pheophorbide a, respectively.
Keywords : green tea; quality evaluation; analysis of tea components; unfavorable substances.
Kazutake Shimada and Tatsuya Higashi
Faculty of Pharmaceutical Sciences, Kanazawa University, 13-1, Takara-machi, Kanazawa 920-0934
(Received 14 March 2002, Accepted 4 April 2002)The usefulness of derivatization with Cookson-type reagents (4-substituted-1,2,4-triazoline-3,5-dione) in the high-performance liquid chromatography/mass spectrometry (LC/MS) of vitamin D (D) compounds was examined. A Cookson-type reagent selectively, rapidly and quantitatively reacted with the s-cis-diene of the D compound to form a Diels-Alder adduct. Glucuronidated and sulfated vitamin D3 (D3) metabolites were converted to the adducts with 4-phenyl-1,2,4-triazoline-3,5-dione, which gave a characteristic product ion indicating the conjugation position by positive-electrospray-MS/MS/MS. Using this technique, we identified 3-epi-24,25-dihydroxyvitamin D3 24-glucuronide together with four other conjugated metabolites in the bile of rats administered 24,25-dihydroxyvitamin D3. This was one of the first reported instances involving the epimerization of the 3-hydroxy group of D compounds. The derivatization with Cookson-type reagents also significantly increased the detection responses of D compounds in positive-atmospheric pressure chemical ionization-MS. Among several Cookson-type reagents, 4-[2-(6,7-dimethoxy-4-methyl-3-oxo-3,4-dihydroquinoxalyl)ethyl]-1,2,4-triazoline -3,5 -dione was most effective in improving the ionization efficiencies of the resulting derivatives. A stable isotope dilution LC/MS/MS method for the determination of plasma 1α-hydroxyvitamin D3 [1α(OH)D3], a prodrug of an active form of D3, was developed employing this derivatization and the additional usual acetylation, in which the limit of quantitation was 25 pg/ml for a 1.0 ml plasma aliquot. Using the developed method, we measured its plasma concentration of a subject orally given 1α(OH)D3 (4 µg). In conclusion, derivatization with Cookson-type reagents was very useful in the LC/MS analysis of D compounds not only to characterize the structure, but also to increase the detection response.
Keywords : vitamin D; liquid chromatography/mass spectrometry; derivatization with Cookson-type reagent; structural elucidation; quantitative analysis.
Nobuhiko Iki
Department of Biomolecular Engineering, Graduate School of Engineering, Tohoku University, Aramaki-Aoba, Aoba-ku, Sendai 980-8579
(Received 26 March 2002, Accepted 11 May 2002)A kinetic differentiation (KD) mode determination system for ultra-trace metal ions consists of the derivatization of metal ions by a spectrophotometric reagent followed by separation and detection of the resulting complexes and the free reagent, which has two attractive feature. The first is high selectivity based on the differentiation of the kinetic stability of metal complexes during separation process. The second is high sensitive detection of the complexes owing to the absence of background absorption. The recent advent of capillary electrophoresis (CE) prompted us to transfer the principle of KD to CE in onto to construct new separation/detection systems for metal ions at the fmol level. For instance, 4-(2-pyridylazo)resorcinol was best separated by the simple CE mode, owing to the 1-OH group of the complex having different pKa values among the center metal ions. By using 2,2'-dihydroxyazobenzene-5,5'-disulfonate (DHABS) and quaternary ammonium ions, ion-association CE was constructed, in which the difference in the ability of ion-association arising from the center metal ion via the -SO3- group determines the separation selectivity. As a result, the requirements for chemical systems in KD-CE were obtained: i) The ligand should possess functional group which is able to convert the character of the center metal ion by means of the reactivity or degree of interaction at the second coordination sphere. ii) An electrophoretic buffer should contain an interacting reagent which can interact with the function group. This guideline successfully produces a new separation system based on the hydrogen-bonding ability of DHABS complexes and poly(ethylene glycohol) through solvated water molecules. Similarly to KD-HPLC, KD-CE exhibited detection selectivity based on kinetic stability of metal complexes. Taking advantage of the simplicity of the separation processes of KD-CE, a CE reactor was constructed to measure the solvolytic dissociation rate of metal complexes which determines the kinetic selectivity in KD mode systems.
Keywords : kinetic differentiation; metal chelates; HPLC; CE; dissociation reaction.
Makoto Sato**, Hiroki Hashimoto**, Tomoyuki Ishikawa**, Jun Matsuda**, Hajime Yoshimura**, Akio Hashimoto*** and Takao Yotsuyanagi****
**Sagamihara R & D Center, Shino-Test Corporation, 2-29-14, Oonodai, Sagamihara-shi, Kanagawa 229-0011
***Product & Technology Development Laboratory, Tanabe Seiyaku Co., Ltd., 16-89, Kashima 3-Chome, Yodogawa-ku, Osaka 532-8505
****Miyagi National College of Technology, 48 Nodayama Shiote, Medeshima, Natori-shi, Miyagi 981-1239
(Received 2 April 2002, Accepted 21 May 2002)The final rule amends the Food and Drug Administration's(FDA) regulations to add certain labeling requirements for the aluminum content in large volume parenterals (LVP) and small volume parenterals (SVP) used in total parenteral nutrition (TPN). The rule also specifies an upper limit of aluminum permitted in LVP's and requires applications to submit to FDA validated assay methods for determining the aluminum content in parenteral drug products. This final rule is effective on January 26, 2003. In this study, the application of kinetic differentiation mode HPLC using 8-quinolinol for the determination of a aluminum in TPN products was developed. The present method enabled the determination of aluminum down to 2 µg/l in TPN solutions (3.3 SD). The recovery of aluminum spiked in these solutions was higher than 90%. The observed values were in good agreement with those by inductively coupled plasma mass spectrometry (ICP-MS). Since the ICP-MS requires large equipments and is inconvenient for in situ analysis, the present method can be expected to provide a simple, selective and rapid technique for the determination of aluminum for the quality control in pharmaceutical industry.
Keywords : aluminum; kinetic-differentiation mode HPLC; 8-quinolinol; TPN; quality control.
Yasuyuki Takeda
Department of Chemistry, Faculty of Science, Chiba University, 1-33 Yayoi-cho, Inage-ku, Chiba 263-8522
(Received 18 March 2002, Accepted 30 April 2002)In order to quantitatively study the effects of diluents as well as the size, structural flexibility, and benzo groups of 18-crown-6 (18C6), benzo-18-crown-6 (B18C6), and dibenzo-18-crown-6 (DB18C6) concerning their extraction-ability and -selectivity for alkali metal ions from the standpoint of equilibrium, constants of the overall extraction (Kex), the distribution for various diluents of low dielectric constants (KD,MLA), and the aqueous ion-pair formation (KMLA) of crown ether (L)-alkali metal picrate (MA) 1:1:1 complexes (MLA) were determined at 25°C; the partition constants of the crown ethers themselves were also measured at 25°C. The distribution behavior of the crown ethers and their MLA complexes can be clearly explained by regular solution theory, except for chloroform. The specific interactions of chloroform with L and MLA were observed. The molar volumes and solubility parameters of the crown ethers and the MLA complexes were determined. A relation between the molar volumes of the MLA complexes and KMLA was considered. For the same alkali metal, the KMLA value decreases in the order 18C6>B18C6>DB18C6 with an increase in the number of benzo groups. The orders of decreasing KMLA value are K+≥Rb+≥Cs+>Na+>Li+ for 18C6, K+>Rb+>Na+ for B18C6, and K+>Rb+>Cs+>Na+ for DB18C6. The KMLA values make major contributions to the extraction selectivity of the three crown ethers (K+>Rb+>Cs+>Na+>Li+). For 18C6 and B18C6, the magnitude of Kex is determined largely by that of KMLA, whereas, for DB18C6, KD,MLA contributes most favorably to Kex. The extraction-ability and -selectivity for the alkali metal picrates and their change with the diluent of these three crown ethers were completely elucidated by the four fundamental equilibrium constants and regular solution theory.
Keywords : extraction selectivity; fundamental equilibrium constants; regular solution theory; crown ethers; alkali metal picrates.
Tetsuo Hashimoto, Yuji Yanagawa and Takahiro Yamaguchi*
Faculty of Science, Niigata University, 8050, Ikarashi-ninocho, Niigata 950-2181
(Received 21 February 2002, Accepted 22 April 2002)Blue thermoluminescence (BTL) phenomena from natural quartz have been attributed to the recombination of Al-hole centers with electrons released from trapped sites. The Al-impurity contents, however, inversely correlate with the BTL-intensity. To approach this interesting correlation, two kinds of quartz slice samples have been studied by the two-dimensional distribution of OH impurity: color center (CC) patterns and thermoluminescence color images (TLCI). Microscopically scanning infrared-spectroscopy showed the presence of Al-OH and Li dependent Al-OH species in natural quartz slices. Brazilian quartz gave a relatively homogeneous distribution of Al-OH as well as CC and BTL patterns. On the other hand, a Madagascan quartz slice offered heterogeneous growth patterns of Al-OH and Li-dependent Al-OH impurity contents, reflecting on unexpectedly inverse correlation of the CC and BTL distributions. These results suggest that mobile hydrogen atoms or hydrogen radicals, produced from the radiolysis of the Al-OH, could operate as a quencher of Al-hole centers for radiation-induced phenomena in quartz. The effects of the Al-hole center influenced by active hydrogen radicals were also confirmed from the difference of the Al-OH concentrations between room-temperature and liquid-nitrogen-temperature irradiations.
Keywords : natural quartz; thermoluminescence; microscopic infrared spectroscopy; hydroxyl group; Al-OH; mapping of impurities; color center images; thermoluminescence color images.
Nobuo Uehara, Hideo Togashi and Tokuo Shimizu
Department of Applied Chemistry, Faculty of Engineering, Utsunomiya University, 7-1-2, Yoto, Utsunomiya-shi, Tochigi 321-8585
(Received 11 March 2002, Accepted 23 April 2002)Ammonium 1,4,7,10,13-pentaoxa-16-azacyclooctadecane-N-carbodithioate (A18CC) and ammonium 1,4,7,10-tetraoxa-13-azacyclopentadecane-N-carbodithioate (A15CC) were synthesized and the capillary zone electorphoresis behavior of their heavy metal chelates was investigated. Only PdII, CoII-A18CC chelates gave recognizable peaks on electorpherograms among 14 kinds of heavy metal chelates of the A18CC and A15CC investigated. The electrophoretic mobilities of the PdII, CoII-A18CC chelates increased with increase of the concentration of alkali metal ion in the migration solution. On the other hand, the electrophoretic mobility of A18CC and A15CC were not altered by addition of any alkali metal ions in the migration solution. By analyzing the relationship between the electrophorertic mobilities of the PdII, CoII-A18CC chelates and the concentration of alkali metal ion by a non-linear least-squares method, the association constants between the PdII, CoII-A18CC and alkali metal ions in the aqueous solution were determined. Lithium ion in the migration solution altered the electrophoretic mobilties of the PdII, CoII-A18CC, which indicated that the chelates associated with lithium ion in the aqueous solution.
Keywords: capillary zone electrophoresis; aza-crown ring; carbodithioate; heavy metal chelates; alkali metal salts.
Yuichi Takaku*, Yuka Kudo**,***, Jyoji Kimura, Takuma Hayashi, Ikuko Ota**, Hidenao Hasegawa and Shinji Ueda*
*Institute for Environmental Sciences, Department of Radioecology, 1-7, Ienomae, Obuchi, Rokkasho-mura, Kamikita-gun, Aomori 039-3212
**Tohoku Nuclear LTD., Advanced Technology of Science, 2-41-14, Higashi Okamisawa, Misawa-shi, Aomori 033-022
***Present Adress Hokkaido University, N10, W5, Kita-ku, Sapporo 060-0810
(Received 10 December 2001, Accepted 26 April 2002)A pre-concentration method for rare-earth elements in environmental water samples using chelating resin disk was developed. All rare-earth elements plus Th and U in environmental water samples were determined by ICP-MS. The preconcentration of all rare-earth elements, (Th and U) and the removal of major elements in seawater, such as alkali and alkaline- earth elements, could be carried out quickly by adjusting the sample's pH to 3. By this method barium could be removed along with other alkaline-earth elements from the sample. This reduced the interference of BaO when using ICP-MS, which allowed the analysis of europium with good precision. Using this method, rare-earth elements in four environmental standard samples (river water standard sample, JAC0031 (Japan Society for Analytical Chemistry), SLRS-3 (NRC Canada), seawater standard sample CASS-3, NASS-4 (NRC Canada)) and five environmental samples in Aomori (seawater 1, sea mingled with brackish water 3, fresh water 1) were measured.
Keywords: Rare-earth elements; Environment water; Chelating resin disk separation; ICP-MS.
Kunihiro Watanabe, Tomoe Iizuka and Masayuki Itagaki*
*Department of pure and applied chemistry, Faculty of Science and Technology, Tokyo University of Science, 2641, Yamazaki, Noda-shi, Chiba 278-8510
(Received 20 March 2002, Accepted 8 May 2002)The removal method of an excess reagent was applied to the fluorometric determination of aluminum using 2,2'-dihydroxyazobenzene (DHAB). The detection limit of the analyte was affected by the fluorescence intensity of an excess reagent, that is, reagent blank. Therefore, the decrease in the fluorescence intensity of an excess reagent has been required for the development of highly sensitive fluorometry. At first in this study, the removal of DHAB was examined using solvent extraction with a small amount of chloroform. Aluminum reacted with DHAB at pH 8 to form an Al-DHAB complex (ratio of composition, Al to DHAB, 1:2). Excess DHAB was removed from the aqueous phase by chloroform-extraction at pH 3 before measuring of the fluorescence on the Al-DHAB complex in the aqueous phase. The ratio of the composition of the Al-DHAB complex varied from 1:2 to 1:1 by changing the pH in aqueous solution. The fluorescence from the Al-DHAB complex was measured by a flow method at an excitation wavelength of 477 nm, and at an emission wavelength of 603 nm. As a result, aluminum was determined by measuring a 1:1 complex of Al-DHAB over a concentration range of from 0.12 to 8 ppb. Moreover, a removal method without extraction solvent was examined by the filtering aqueous phase using a filter phase separator. The DHAB was deposited in the aqueous solution at pH 3 because of the insolubility of the free DHAB. On the other hand, the Al-DHAB complex was stable in the aqueous phase, that is, the filtrate after filtration by the filter phase separator. Excess DHAB was removed at 74% from the aqueous phase. Therefore, the fluorometric intensity of the reagent blank decreased to 1/4. As a result, aluminum was determined over the range from 0.12 to 300 ppb. The present method was applied to the determination of aluminum in a tap-water sample.
Keywords: removal of excess reagent; dihydroxyazobenzene; fluorometry; aluminum, filter phase separator.
Kunihiro Watanabe, Takashi Watanabe and Masayuki Itagaki*
*Department of Pure and Applied Chemistry, Faculty of Science and Technology, Tokyo University of Science, 2641, Yamazaki, Noda-shi, Chiba 278-8510
(Received 15 February 2002, Accepted 14 May 2002)A flow injection analysis method (FIA) for the determination of manganese(II) was investigated using azo compounds, which were oxidized with KIO4 to form colorless azoxy compounds. The oxidation reaction of the azo compounds was accelerated in the presence of MnII. The decreased absorbance of the azo compounds was directly proportional to the concentration of MnII. Therefore, the conditions of the catalytic determination of MnII were examined by FIA. 1-amino-8-hydroxy-7-(o-hydroxyl-p-methylphenylazo)-3,6-naphthalenedisulfonic acid (p-CH3) among the examined azo compounds was excellent in sensitivity for MnII determination. The flow system used had three channels. Each carrier (distilled water) and reagent (p-CH3) solution was pumped at 1.0 cm3/min. A sample solution was injected manually into the carrier stream. Then, a KIO4 solution was mixed with a reagent solution containing the sample. As a result, MnII could be determined in the concentration range of 0.3 to 3 ppb (ng cm-3) by monitoring at 608 nm. The detection limit of MnII was 0.08 ppb (S/N=5). A large amount of MgII interfered positively with the determination of MnII. The decreased absorbance based on MgII was measured after masking MnII with triethanolamine. Then, the decreased absorbance of only MnII was calculated by subtracting the absorbance of MgII from the total absorbance in the presence of MnII and MgII. The present method was successfully applied to the determination of trace MnII in drinking water without the preconcentration of MnII. The recommended conditions are as follows: reaction pH 9.4; temperature, 30°C; p-CH3, 1.2×10-4 M (flow rate, 1.0 cm3/min); KIO4, 4.0×10-5 M (flow rate, 1.0 cm3/min); reaction coil length, 9 m (i.d. 1 mm); injection volume of sample, 1.0 cm3. 15 samples could be analyzed per hour.
Keywords: catalytic analysis; MnII; drinking water; 1-amino-8-hydroxy-7-(o-hydroxy-p-methylphenylazo)-3,6-naphthalenedisulfonic acid.
Takio Kitahara, Jiro Takano*, Hideaki Kitami** and Tetsuo Watanabe***
*Derpartment of Chemistry, School of Science, Tokai University, 1117, Kitamaname, Hiratsuka-shi, Kanagawa 259-1292
**Sougou Kankyou Bunseki Co., Ltd., 1-13-2, Kamoi, Midori-ku, Yokohama-shi, 226-0003
***Department of Resources and Environmental Science, School of Humanities and Culture, Tokai University, 1117, Kitamaname, Hiratsuka-shi, Kanagawa 259-1292
(Received 28 December 2001, Accepted 13 May 2002)We have developed a solid-phase extraction method for the simultaneous determination of alkylphenols, bisphenol A and 17β-estradiol in distilled water and river water by high-performance liquid chromatography (HPLC) with the ultraviolet detector (UV). As a result, good linearity of the calibration curve was obtained in the concentration range from 0.1 mg/l to 5 mg/l. Acetone was recommended for the elution of these compounds from the solid phases. The recoveries for these compounds from river water at a concentration of 1 mg/l was 86.4~93.8%, and the relative standard deviation was 5.1~7.9% by the activated-carbon column method. This analytical method could be successfully applied to the determination of these compounds in river water.
Keywords: HPLC-UV; solid phase extraction; alkylphenols; bisphenol A; 17β-estradiol.
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