BUNSEKI KAGAKU Abstracts

Vol. 56 No. 10

October, 2007


Research Papers
Estimation of On-Capillary Dissociation Characteristics of Zn(II) Complex with 1,5-bis(2-hydroxy-5-sulfophenyl)-3-cyanoformazan by a Capillary Electrophoretic Reactor
Kazutaka Ogasawara1, Toru Takahashi1, Nobuhiko Iki1 and Hitoshi Hoshino1
1 Division of Environmentally Benign Systems, Graduate School of Environmental Studies, Tohoku University, 6−6−20, Aoba, Aramaki, Aoba-ku, Sendai-shi, Miyagi 980−8579
(Received 15 June 2007, Accepted 22 August 2007)

The on-capillary dissociation reaction properties of the Zn(II) complex with 1,5-bis(2-hydroxy-5-sulfophenyl)-3-cyanoformazan ([Zn-HSCF]) have been studied using the Capillary Electrophoretic Reactor (CER). The solvolytic dissociation reaction rate constant (kd) of [Zn-HSCF] under the optimal conditions for CE separation at pH 8.80 was determined to be 4.3×10−5 (half-life period was 4.5 hours) with ligand substitution mode CER. Thus, it is clear that [Zn-HSCF] is extremely inert at pH 8.80 in a kinetic sense. On the other hand, [Zn-HSCF] was not detected at pH 5.10 in the CE system. The kd value at pH 5.10 was determined to be 3.7×1 by a batch-wise method with a ligand substitution technique using EDTA as a substitution ligand. The half-life period was calculated to be only 3 minutes, suggesting that almost all [Zn-HSCF] dissociates on the time scale of CE separation at pH 5.10. From an estimation of the free ligand concentration profiles in the capillary during CE separation processes, it was shown that CE separation gives an almost thermodynamically unsuitable environment for [Zn-HSCF] at both pH 8.80 and 5.10. Thus, it is concluded that the detection selectivity of metal complexes in the pre-capillary derivatization CE depends on the kinetic stability, i.e. the dissociation reaction inertness of the metal complexes, though their thermodynamic stability is necessary only for the pre-capillary derivatization step.

Keywords : metal complex; dissociation kinetic analysis; capillary electrophoresis; dissociation rate constant; detection selectivity.

Notes
Reversed-Phase HPLC Separation of 1,2-Diacylglycerol Regioisomers
Chisato Aizawa1, Rieko Shiozaki1 and Yutaka Itabashi2
1 Division of Marine Life Science, Chair of Marine Bioresources Chemistry, Graduate School of Fisheries Sciences, Hokkaido University, 3−1−1, Minato-cho, Hakodate-shi, Hokkaido 041−8611
2 Division of Marine Life Science, Laboratory of Marine Bioresources Chemistry, Faculty of Fisheries Sciences, Hokkaido University, 3−1−1, Minato-cho, Hakodate-shi, Hokkaido 041−8611
(Received 18 April 2007, Accepted 21 August 2007)

We investigated the separation of the regioisomers (reverse isomers) of 1,2-diacyl-rac-glycerols by reversed-phase HPLC on columns containing endcapped and non-endcapped ODS phases. The reverse isomers of 1,2-diacylglycerols, having various pairs of acyl groups including saturated and unsaturated chains, were chromatographed as 3,5-dinitrophenylurethanes (DNPU) using acetonitorile as the mobile phase. Baseline separations were achieved for the reverse isomers of very different pairs of acyl groups, such as caprylate/palmitate and stearate/arachidonate, on both endcapped and non-endcapped ODS columns, which retained longer less-polar isomers with a lower degree of unsaturation or shorter chain at the sn-1(3) position. The latter columns, however, markedly shortened the elution times of the derivatives compared to the former columns. Most commercially available ODS columns are fully endcapped so as to decrease any undesirable influence of residual silanol. The present study, however, demonstrates that non-endcapped ODS phases are more suitable for reverse isomer separation than fully endcapped ones.

Keywords : 1,2-diacylglycerols; reverse isomers; 3,5-dinitrophenylurethanes; reversed-phase HPLC; non-endcapped ODS.

Accounts
Highly Sensitive Analysis Based on Laser-Induced Fluorescence Detection/Capillary Electrophoresis
Takashi Kaneta1,2
1 Department of Applied Chemistry, Graduate School of Engineering, Kyushu University, 744 Motooka, Nishi-ku, Fukuoka-shi, Fukuoka 819−0395
2 Division of Translational Research, Center of Future Chemistry, Kyushu University, 744 Motooka, Nishi-ku, Fukuoka-shi, Fukuoka 819−0395
(Received 5 April 2007, Accepted 1 June 2007)

Laser-induced fluorescence detection using diode lasers as excitation light sources has been applied to the highly sensitive analysis of polyaromatic hydrocarbons, amino acids, DNA, and proteins. Diode lasers emitting at the near-infrared to red region were employed for direct and indirect fluorescence detections. In addition, to enhance the sensitivity in capillary electrophoresis, Hadamard transform capillary electrophoresis has been developed. The method includes multiple injection, followed by an inverse Hadamard transformation. Optically gated injection, electrokinetic injection using a microchip, and electrokinetic injection using a laser-fabricated capillary have been developed for achieving multiple sample injection. These methods have permitted multiple sample injection in capillary electrophoresis. The results obtained by Hadamard transform capillary electrophoresis showed a significant improvement in the S/N.

Keywords : capillary electrophoresis; laser-induced fluorescence detection; diode laser; Hadamard transformation.

Research Papers
Measurement of Hydrated Water in D-Glucose Powder Using THz-Wave Spectroscopy
Kaori Abe1, Shin'ichiro Hayashi1,2, Norihito Doki3, Chiko Otani2, Kodo Kawase1,2,4, Teruo Miyazawa1 and Yuichi Ogawa1
1 Graduate school of Agricultural Science, Tohoku University, 1−1, Amamiyamachi, Tsutsumidori, Aoba-ku, Sendai-shi, Miyagi 981−8555
2 Terahertz-Wave Research Program, Riken, 519−1399, Aoba, Aramaki, Aoba-ku, Sendai-shi, Miyagi 980−0845
3 Department of Chemical Engineering, Iwate University, 4−3−5, Ueda, Morioka-shi, Iwate 020−8551
4 Graduate school of Engineering, Nagoya University, Furocho, Tikusa-ku, Nagoya-shi, Aichi 464−8603
(Received 29 January 2007, Accepted 22 June 2007)

In this paper, we introduce a new method to measure the amount of water of crystallization in D-glucose powder using terahertz (THz) wave spectroscopy. We measured five crystalline D-glucose samples: one anhydrous, one monohydrate, and three in various states of partial dehydration, whose water content was measured independently by using Karl Fischer's method. By analyzing the THz absorption spectra, particularly the absorption peaks at 60.3, 65.6, and 80.5 c, which are strongly correlated with the hydration ratio, we could obtain a highly reliable analytical curve, with a correlation coefficient of 0.9509 and a standard error of prediction of 0.714. This study suggests the possibility of measuring the water of crystallization nondestructively, without using an organic solvent.

Keywords : terahertz spectroscopy; Karl Fischer's method; hydrate; glucose.

Decomposition Characteristics of Various Organic Compounds in Chemical Oxygen Demand Measurement
Yoichi Kikuchi1, Satomi Kakizaki1 and Rie Koizumi1
1 Laboratory of Chemistry, Faculty of Education, Iwate University, 3−18−33, Ueda, Morioka-shi, Iwate 020−8550
(Received 19 March 2007, Accepted 2 July 2007)

The decomposition ratio of various organic compounds in chemical oxygen demand measurements using potassium permanganate (CODMn) was studied as a function of the decomposition time. We focused on the relationship between decomposition behaviors of organic compound including simple compounds as a partial structure and those of these simple organic compounds. The decomposition ratio of phenols by the CODMn method was comparatively high for a short decomposition time. The phenol moiety in Triton X-100 and tyrosine was decomposed as well as phenol. The decomposition behaviors of non-ionic surfactants were successfully explained based on those of simple organic compounds. As mentioned above, the relationship between the decomposition ratio of simple organic compounds and that of organic compounds including these simple organic compounds as a partial structure was revealed.

Keywords : COD; potassium permanganate; decomposition ratio of organic compounds; non-ionic surfactant.

Technical Papers
Preparation of a Pb-Type Ligand Exchange Column for Liquid Chromatography/Mass Spectrometric Analysis of Saccharides
Keiji Gamoh1, Chiyomi Nakao1, Katsumi Hishida2 and Hiroo Wada2
1 Faculty of Education, Kochi University, 2−5−1, Akebono-cho, Kochi-shi, Kochi 780−8520
2 Shinwa Chemical Industry Ltd., 50−2, Kagekatsu-cho, Hushimi-ku, Kyoto-shi, Kyoto 612−8307
(Received 28 March 2007, Accepted 26 June 2007)

A ligand-exchange liquid chromatography/mass spectrometric (LC/MS) analysis of mono- and oligo-saccharides has been developed. The successful separation and detection of a mixture of seven monosaccharides, four disaccharides and two trisaccharides was performed using an improved ligand-exchange column, which was a semi-rigid styrene-divinylbenzene copolymer-based Pb-type cation-exchange resin (ULTRON PS-80P/5S), and electrospray ionization mass spectrometry (ESI-MS). Water was used as a mobile phase to separate the above-mentioned saccharides within 12 min. The ESI interface was used in a negative-ion mode for LC/MS, which produced reasonable signals from their negative ions ([M−H]). The effect of aqueous ammonia, which was used as an additive to the eluent, was also examined. An increase of the detection sensitivities of the saccharides was observed when aqueous ammonia was used as the additive at a concentration of 2% (v/v). The effects of the separation and ionization parameters, column temperature and cone voltage on the sensitivity and linearity were examined. Linear plots of the peak area versus the concentration were obtained for MS detection over the range of 5〜1000 μM (r2=0.951〜0.999) for each saccharide. The detection limits of the target saccharides, calculated at S/N=3, ranged from 0.25 to 2.00 pmol. The reproducibility of the retention times and the peak areas were 0.66〜1.2% and 0.96〜2.86%, respectively. Then, those results were compared with the results by using a Ca-type ligand-exchange column, which confirmed the usefulness of the Pb-type ligand-exchange LC/MS analysis of mono- and oligo-saccharides.

Keywords : mono- and oligo-saccharide; electrospray ionization; liquid chromatography/mass spectrometry (LC/MS); semimicro column; ligand exchange mode.

Analysis of Strontium Titanate by Helium Glow-Discharge Mass Spectrometry Using Dummy Cathode
Shinji Itoh1, Nobutaka Oguro1, Toshiya Ogiwara1 and Takeshi Kobayashi1
1 National Institute for Materials Science, Materials Analysis Station, 1−2−1, Sengen, Tsukuba-shi, Ibaraki 305−0047
(Received 24 May 2007, Accepted 17 July 2007)

A dummy cathode brings about the sputtering of non-conductive ceramics, like SrTiO3 in a helium glow discharge ion source. This study addresses that phenomenon. A dummy cathode with an outer diameter of 20 mm and an aperture diameter of 5 mm was prepared from a Ta sheet using electrical-discharge machining. A Ta plate with a 10 mm aperture diameter was used as an anode plate. The optimal electric discharge parameter was obtained at a He flow rate of 10 mL/min and a discharge voltage of 2 kV. The discharge current was about 2 mA. The ion intensities of Ti, Sr, and Ta reached 10−10 A level in peak-area integrated intensity at a mass resolution of 4000. The ion intensity the ratios to Ta, Ti : Ta and Sr : Ta, were both 0.26 : 1. Under these conditions, five data sets were acquired a after pre-discharge for 60 min, which proved that a stable glow discharge continued for 170 min or longer. The relative sensitivity factors of O and Sr to Ti, RSFO,Ti, and RSFSr,Ti, were obtained using the measurement of a SrTiO3 single crystal; they were, respectively, 0.179 and 2.099.

Keywords : helium glow discharge; strontium titanate; dummy cathode; relative sensitivity factors.

Spectrophotometric Determination of Quinine and Its Related Drugs with o-Sulfophenylfluorone and Copper(II)
Chikako Yamazaki1, Hiroshi Tominaga1, Megumi Samma1, Rie Isono1, Shinichiro Kamino1, Takako Yamaguchi1 and Yoshikazu Fujita1
1 Osaka University of Pharmaceutical Sciences, 4−20−1, Nasahara, Takatsuki-shi, Osaka 569−1094
(Received 8 March 2007, Accepted 21 July 2007)

A novel spectrophotometric method was established for the determination of quinine and its related drugs based on ternary complex formation among o-sulfophenylfluorone, copper(II) and quinine. In the determination of quinine, Beer's low is obeyed in the range of 0.2〜3.2 μg c. The effective molar absorptivity at 590 nm and the relative standard deviation were 2.0×105 dm3 mol−1 cm−1 and 2.0% (n=6), respectively. The method was successfully applied to assays of quinine and its related drugs in pharmaceutical preparations. In addition, it was suggested that the ternary complex showed thermochromism.

Keywords : quinine and its related drugs; spectrophotometry; o-sulfophenylfluorone and copper(II); ternary complex; thermochromism.

Notes
Elemental Analyses of Suspended Particulate Matter Collected on Tape Filters by Electron Probe Microanalyzer
Jo Takeuchi1 and Toshiaki Inoue2
1 Kawasaki Municipal Research Institute for Environmental Protection, 20−2, Tajima-cho, Kawasaki-ku, Kawasaki-shi, Kanagawa 210−0853
2 Kawasaki Air & Water Pollution Monitoring Center, 2−25, Miyamoto-cho, Kawasaki-ku, Kawasaki-shi, Kanagawa 210−0004
(Received 25 April 2007, Accepted 5 July 2007)

An electron probe microanalyzer (EPMA) was applied to suspended particulate matter (SPM), hourly collected by a β-ray attenuation method SPM automatic sampler with a polytetrafluoroethylene (PTFE) tape filter, at a monitoring station in Nakahara, Kawasaki, Kanagawa, at 17 : 00 on April 13th and at 7 : 00 on April 19th, 2006. From the results, it was inferred that inorganic secondary particles were partly collected on April 13th, since N and S were detected and Asian dust was collected on April 19th, because the detected chemical elements were very similar to those of Asian dust collected in China in the past. Also, it was found that particles on a carbon-coated PTFE filter could be directly observed and analyzed by EPMA.

Keywords : suspended particulate matter; electron probe microanalyzer; inorganic secondary particles; asian dust.

Analytical Reports
Sodium Carbonate Fusion/Alkaline Solution Method for the Determination of B in SiC by Inductively Coupled Plasma Atomic Emission Spectrometry
Mitsuyoshi Watanabe1, Satoko Otsuki1 and Shigeharu Suzuki1
1 Materials Reserch Laboratory, NGK Insulators, Ltd., 2−56, Suda-chou, Mizuho-ku, Nagoya-shi, Aichi 467−8530
(Received 16 February 2007, Accepted 25 June 2007)

Boron determination in a silicon carbide (SiC) sample was carried out by a dissolution technique with an alkaline solution. Using the proposed method, a 0.50 g sample of silicon carbide powder was placed in a platinum dish and fused with 3.0 g of sodium carbonate. After the cake was dissolved in water, boron was determined by inductively coupled plasma atomic emission spectrometry (ICP-AES). Through this method, it was possible to determine with high precision the amount of boron in the SiC sample.

Keywords : silicon carbide; total boron; fusion with sodium carbonate; alkaline solution; ICP-AES.

Digest of Doctoral Dissertation
Development of Chelating Resin-Packed Minicolumn for Multielement Preconcentration and Determination of Trace Metals in Natural Water
Yanbei Zhu
Environmental Standard Section, Inorganic Analytical Chemistry Division, National Metrology Institute of Japan, National Institute of Advanced Industrial Science and Technology, 1−1−1, Umezono, Tsukuba-shi, Ibaraki 305−8563
(Awarded by Nagoya University dated March 25, 2005)

Trace metals in natural water are sensitive indicators of geochemical processes and reactions, environmental pollutions, and bioactivities, though these elements are present in extremely low concentrations. Determination of trace metals in natural water is still a challenge for analysts, even using the most advanced available analytical instrument such as ICP-MS. In order to overcome this difficulty, a chelating resin-packed minicolumn was developed to preconcentrate trace metals in natural water. The minicolumn was constructed by packing a slurry of Chelex 100 resin into the space of the outlet of a syringe filter (DISMIC-25HP, ADVANTEC), which was then capped with another syringe filter (Millex-LH, Nihon Millipore Kogyo). Furthermore, a procedure for the preconcentration of trace metals in natural water using the present minicolumn was established by carefully optimizing each operating parameter. As a result, a concentration factor of 20-fold was achieved for trace metals using only 50 mL of a natural water sample, where the recovery values for most of the trace metals were more than 80% with a standard deviation less than 5%. The effectiveness of the present analytical method was assessed by determining trace metals in seawater certified reference materials (NASS-5, CASS-3, and CASS-4). Furthermore, determination of trace metals in seawater, river water, and mineral water samples was carried out to assess the environmental pollution of trace metals in natural water and the mineral nutriment in mineral water, respectively.

(Received April 26, 2007)
Keywords : chelating resin-packed minicolumn; preconcentration; trace metals; natural water; ICP-MS; certified reference material.

Metallomics Research on Multielement Analysis and Chemical Speciation of Biological Samples
Takuya Hasegawa
Department of Applied Chemistry, Graduate School of Engineering, Nagoya University, Furo-cho, Chikusa-ku, Nagoya-shi, Aichi 464−8603
(Awarded by Nagoya University dated January 31, 2007)

In relation to metallomics research, the multielement determination and chemical speciation of major-to-ultratrace elements in biological samples were investigated by ICP-AES and ICP-MS with the aid of HPLC. First, the determination of multielements in human blood serum donated from healthy volunteers and disease patients was carried out. As a result, it has been suggested that a multielement analysis of serum may be available for the medical diagnosis of specific diseases. Next, the chemical speciation of mercury and the assay of ALP in salmon egg cell cytoplasm were performed using CHAPS-coated ODS and the SEC columns. The existence of some protein-binding mercury and cysteine-binding mercury in salmon egg cell cytoplasm was confirmed. The analytical results indicate that Hg in salmon egg cell cytoplasm binds with proteins containing selenocysteine and/or cysteine residues. In an ALP assay study, the existence of hydrophilic ALP and hydrophobic conjugated proteins of ALP in salmon egg cell cytoplasm was found. Finally, a phosphatidylcholine-coated ODS column was newly developed and applied to a speciation analysis of arsenic compounds in human blood serum. As a result, it was found that arsenite dosed in the vein of a leukemia patient for therapeutic treatment was converted mainly to monomethylarsonic acid and dimethylarsinic acid.

(Received June 6, 2007)
Keywords : metallomics; mercury; arsenic; alkaline phosphatase; multielement analysis; ICP-MS; phosphatidylcholine-coated ODS column.

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