@article{Aoki2004,

title = {Differing involvement of sulfoquinovosyl diacylglycerol in photosystem II in two species of unicellular cyanobacteria},

author = {Motohide Aoki and Norihiro Sato and Ayano Meguro and Mikio Tsuzuki},

url = {http://blackwell-synergy.com/doi/abs/10.1111/j.1432-1033.2003.03970.x http://doi.wiley.com/10.1111/j.1432-1033.2003.03970.x},

doi = {10.1111/j.1432-1033.2003.03970.x},

issn = {00142956},

year  = {2004},

date = {2004-01-01},

journal = {European Journal of Biochemistry},

volume = {271},

number = {4},

pages = {685--693},

institution = {School of Life Science, Tokyo University of Pharmacy and Life Science, Horinouchi, Hachioji, Tokyo, Japan.},

abstract = {Sulfoquinovosyl diacylglycerol (SQDG) is involved in the maintenance of photosystem II (PSII) activity in Chlamydomonas reinhardtiiMinoda, A., Sato, N., Nozaki, H., Okada, K., Takahashi, H., Sonoike, K. & Tsuzuki, M. et al. (2002) Eur. J. Biochem.269, 2353-2358. To understand the spread of the taxa in which PSII interacts with SQDG, especially in cyanobacteria, we produced a mutant defective in the putative sqdB gene responsible for SQDG synthesis from two cyanobacteria, Synechocystis sp. PCC6803 and Synechococcus sp. PCC7942. The mutant of PCC6803, designated SD1, lacked SQDG synthetic ability and required SQDG supplementation for its growth. After transfer from SQDG-supplemented to SQDG-free conditions, SD1 showed decreased net photosynthetic and PSII activities on a chlorophyll (Chl) basis with a decrease in the SQDG content. Moreover, the sensitivity of PSII activity to 3-(3,4-dichlorophenyl)-1,1-dimethylurea and atrazine was increased in SD1. However, SD1 maintained normal amounts of cytochrome b559 and D1 protein (the subunits comprising the PSII complex) on a Chl basis, indicating that the PSII complex content changed little, irrespective of a decrease in the SQDG content. These results suggest that the role of SQDG is the conservation of the PSII properties in PCC6803, consistent with the results obtained with C. reinhardtii. In contrast, the SQDG-null mutant of PCC7942 showed the normal level of PSII activity with little effect on its sensitivity to PSII herbicides. Therefore, the difference in the SQDG requirement for PSII is species-specific in cyanobacteria; this could be of use when investigating the molecular evolution of the PSII complex.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Umemura2003,

title = {Seasonal change in the level and the chemical forms of aluminum in soil solution under a Japanese cedar forest.},

author = {Umemura, Tomonari and Usami, Yosuke and Aizawa, Sho-ichi and Tsunoda, Kin-ichi and Satake, Ken-ichi.},

doi = {10.1016/S0048-9697(03)00364-4},

issn = {0048-9697},

year  = {2003},

date = {2003-01-01},

journal = {Science of the Total Environment},

volume = {317},

number = {1-3},

pages = {149--157},

publisher = {Elsevier Science Ltd.},

abstract = {The level of dissolved Al and its chem. forms in soil solns. consecutively collected by a porous cup vacuum sampler were monitored over a period from Jan. 2001 to Dec. 2001 at a Japanese cedar (Cryptomeria japonica) forestry susceptible to acid deposition to characterize current soil dynamics and to evaluate potential tree damages. Distinction and characterization of Al species with differential toxicities were performed by 2 complementary speciation techniques; cation-exchange HPLC with fluorometric detection using 8-hydroxyquinoline-5-sulfonic acid (HQS) and size-fractionation/inductively coupled plasma at. emission spectrometry (ICP-AES). The concns. of free Al (mainly Al3+ and Al(OH)2+) and inert Al (existing as the complexed and/or colloidal forms) ranged between 0-150 and 10-50$mu$M, resp. The concns. of inert Al were mostly <40$mu$M during an annual cycle and showed no marked seasonal variation, while free Al concns. showed a clear tendency to increase in the spring and summer seasons (in the period from Apr. to August) probably due to the enhanced activity of microbial nitrification and the resultant soil acidification. Major cations and anions were also regularly detd. and their seasonal changes were correlated with that of the dissolved Al concn. Correlations between total Al (mainly existing as free Al) and the related species (and environmental conditions) were as follows: Al and Mg (R=0.96, p <0.01), Al and Ca (R=0.97, p <0.01), Al and NO3- (R=0.68, p <0.01), Al and temp. (R=0.68, p <0.01), Al and soln. pH (R=-0.61, p <0.01), soln. pH and NO3- (R=-0.65, p <0.01). [on SciFinder(R)]},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Tsunoda2003,

title = {Liquid core/cladding optical fiber waveguide for capillary cells in chemical analysis.},

author = {Tsunoda, Kinichi and Umemura, Tomonari.},

issn = {0387-1037},

year  = {2003},

date = {2003-01-01},

journal = {Kemikaru Enjiniyaringu},

volume = {48},

number = {10},

pages = {780--783},

publisher = {Kagaku Kogyosha},

abstract = {A review. [on SciFinder(R)]},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Tsunoda2003a,

title = {Adsorption of methylene blue onto silylated silica surfaces, studied using visible attenuated total reflection spectroscopy with a slab optical waveguide.},

author = {Tsunoda, Kin-Ichi and Umemura, Tomonari and Ueno, Hiroko and Okuno, Eriko and Akaiwa, Hideo.},

doi = {10.1366/000370203769699153},

issn = {0003-7028},

year  = {2003},

date = {2003-01-01},

journal = {Applied Spectroscopy},

volume = {57},

number = {10},

pages = {1273--1277},

publisher = {Society for Applied Spectroscopy},

abstract = {The behavior of methylene blue (MB) mols. at silica/water and silylated silica/water interfaces was examd. using visible attenuated total reflection spectroscopy with a slab optical waveguide (SOWG). An alkyl silane coating changed the adsorbed form of MB on the surface from a dimer ($łambda$max = 600 nm, bare SiO2 surface) to a monomer ($łambda$max = 670 nm), and the C no. of the silylation reagent influenced the amt. of adsorption and the orientation of the mol. Moreover, the addn. of an anionic surfactant, dodecylbenzenesulfonate (DBS), caused the deposition of MB/DBS ion pairs, which gave an identical attenuated total reflection (ATR) spectrum to that of the dimer. Linear dichroism measurements revealed that the ion pairs were adsorbed onto the silylated SiO2 surface randomly in terms of the orientation angle of MB, while the MB monomer was strongly oriented, i.e., the direction of the transition moment of MB roughly parallels the surface plane. This difference in the orientation angles of the adsorbed species can be utilized for their selective detection using polarization SOWG measurements. [on SciFinder(R)]},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Tsunoda2003b,

title = {Characteristics of liquid core waveguide cell made of low-refractive-index polymer and its application to the spectrophotometric determination of sulfur in a steel sample.},

author = {Tsunoda, In-Ichi and Umemura, Tomonari and Watanabe, Takashi and Takiguchi, Hiromi and Asano, Hitoshi and Itabashi, Hideyuki and Ishibashi, Yohichi and Sato, Sakae.},

issn = {0021-1575},

year  = {2003},

date = {2003-01-01},

journal = {Tetsu to Hagane},

volume = {89},

number = {9},

pages = {99--101},

publisher = {Iron and Steel Institute of Japan},

abstract = {Teflon AF-2400 capillary (internal diam. 0.29 mm, o.d. 0.5 mm) was used as a liq. core waveguide cell with an aq. soln. sample. The refractive index of the Teflon AF-2400 capillary (n = 1.29 (632.8 nm)) is lower than that of H2O (no = 1.33), thus, the capillary formed a liq. core waveguide and was elongated up to 117 cm long. The sensitivity in detecting methylene blue with the 30 cm capillary cell was enhanced ∼32-fold in comparison with that of a conventional cell (1 cm). The cell (30 cm) was applied to the spectrophotometric detn. of S in a std. steel sample after distn. of S as H2S. [on SciFinder(R)]},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Abe2003,

title = {Decomposition of phenolic endocrine disrupting chemicals by potassium permanganate and $gamma$-ray irradiation.},

author = {Abe, Yasuhiro and Takigami, Machiko and Sugino, Kouji and Taguchi, Mitsumasa and Kojima, Takuji and Umemura, Tomonari and Tsunoda, Kin-ichi.},

doi = {10.1246/bcsj.76.1681},

issn = {0009-2673},

year  = {2003},

date = {2003-01-01},

journal = {Bulletin of the Chemical Society of Japan},

volume = {76},

number = {8},

pages = {1681--1685},

publisher = {Chemical Society of Japan},

abstract = {The decompn. of phenolic endocrine disrupting chems. (P-EDCs), such as phenol, 4-tert-butylphenol (BuP), and bisphenol A (BPA), in aq. solns. by potassium permanganate was studied, and its efficiency was compared with that of hydroxyl radicals generated by 60Co $gamma$-ray irradn. Various org. acids and inorg. carbon were formed in the decompn. of P-EDCs due to either KMnO4 or OH. They were formed via direct arom. ring cleavage in the case of KMnO4 and via OH addn.-substitution reactions, followed by arom. ring cleavage, in the case of OH. Comparing the decrease in the P-EDCs based on the no. of electrons, the amt. of KMnO4 spent to completely eliminate BuP and BPA was comparable to that of OH. Although three times more KMnO4 was needed for phenol decompn. than OH, the complete conversion of phenol into org. acids and inorg. carbon was achieved with 720 $mu$M of electrons in both cases. [on SciFinder(R)]},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Takiguchi2003,

title = {Liquid/liquid optical waveguides using sheath flow as a new tool for liquid/liquid interfacial measurements.},

author = {Takiguchi, Hiromi and Odake, Tamao and Ozaki, Manabu and Umemura, Tomonari and Tsunoda, Kin-Ichi.},

doi = {10.1366/000370203322259011},

issn = {0003-7028},

year  = {2003},

date = {2003-01-01},

journal = {Applied Spectroscopy},

volume = {57},

number = {8},

pages = {1039--1041},

publisher = {Society for Applied Spectroscopy},

abstract = {A liq./liq. optical waveguide was constructed using a sheath flow. Since the refractive index of an org. solvent is generally higher than that of H2O (nD = 1.33), light introduced into the inner org. flow should proceed with total multi-reflection within the inner flow, so that the inner part of the sheath flow acts as the core of an optical waveguide. This sheath flow liq./liq. optical waveguide was stable and showed no substantial background scattering. Also, it is applicable to both miscible and immiscible liq./liq. interfaces. Thus, it may become a new tool for studying liq./liq. interfaces as well as for sensitive optical measurements. [on SciFinder(R)]},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Tsunoda2003c,

title = {What can nano-analytical chemistry do for speciation analysis of trace elements?.},

author = {Tsunoda, Kin-ichi and Umemura, Tomonari.},

issn = {0451-2014},

year  = {2003},

date = {2003-01-01},

journal = {Kagaku Kogyo},

volume = {54},

number = {6},

pages = {439--444},

publisher = {Kagaku Kogyosha},

abstract = {A review. Discussed are speciation anal., current status of speciation anal., and expectation on nano anal. [on SciFinder(R)]},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Sato2003,

title = {Involvement of sulfoquinovosyl diacylglycerol in the structural integrity and heat-tolerance of photosystem II.},

author = {Norihiro Sato and Motohide Aoki and Yukihiro Maru and Kintake Sonoike and Ayumi Minoda and Mikio. Tsuzuki},

doi = {10.1007/s00425-003-0992-9},

issn = {0032-0935},

year  = {2003},

date = {2003-01-01},

journal = {Planta},

volume = {217},

number = {2},

pages = {245--251},

publisher = {Springer-Verlag},

abstract = {To examine the role of sulfoquinovosyl diacylglycerol (SQDG) in thylakoid membranes, the authors compared the structural and functional properties of photosystem II (PSII) between a mutant of Chlamydomonas reinhardtii defective in SQDG (hf-2) and the wild type. The PSII core complex of hf-2, as compared with that of the wild type, showed structural fragility when solubilized with a detergent, dodecyl $beta$-D-maltoside, suggesting that the phys. properties of the PSII complex were altered by the loss of SQDG. On the other hand, exposure of the cells to 41° for 120 min in the dark decreased the PSII activity to 70% and 50% of the initial levels in the wild type and hf-2, resp., which implies that the PSII activity, in the absence of SQDG, becomes less stable under heat-stress conditions. PSII inactivated to 60% of the initial level by dark incubation at 41° was reactivated by following illumination even at 41° to more than 90% in the wild type, but only to 70% in hf-2. These results suggest that PSII inactivated by heat recovers through some mechanism dependent on light, and that SQDG participates in functioning of the mechanism. The conformational disorder of PSII caused by the defect in SQDG might be correlated with the increased susceptibility of its activity to heat-stress. [on SciFinder(R)]},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Umemura2002,

title = {Sensitive measurement of methylene blue active substances by attenuated total reflection spectrometry with a trimethylsilane-modified glass slab optical waveguide.},

author = {Umemura, Tomonari and Kasuya, Yuichi and Odake, Tamao and Tsunoda, Kin-Ichi.},

doi = {10.1039/b105281k},

issn = {0003-2654},

year  = {2002},

date = {2002-01-01},

journal = {Analyst (Cambridge, United Kingdom)},

volume = {127},

number = {1},

pages = {149--152},

publisher = {Royal Society of Chemistry},

abstract = {Attenuated total reflection spectrometry with a slab optical waveguide (SOWG) was developed as a rapid and sensitive measurement of total anionic surfactants by the methylene blue active substance (MBAS) method. A fused-SiO2 sheet, used as a guiding layer, was modified with tri-Me silane (TMS) to ext. and conc. the MBASs on the SOWG surface. Based on preliminary studies of the adsorption behavior and visible ATR spectrum of MB on the modified SiO2 surface, a detection wavelength of 600 nm was chosen for the sensitive measurement of anionic surfactants. With a MB concn. of 10 $mu$M in the measurement soln., the calibration curve for a typical anionic surfactant, Na dodecylbenzenesulfonate, was linear up to 0.6 $mu$M and the detection limit was 0.07 $mu$M. The proposed method was applied to the detn. of total anionic surfactants in river water. [on SciFinder(R)]},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Tsunoda2001,

title = {Application of liquid core waveguide to spectrochemical analysis.},

author = {Tsunoda, Kinichi and Umemura, Tomonari.},

issn = {0386-2178},

year  = {2001},

date = {2001-01-01},

journal = {Bunseki},

number = {12},

pages = {668--673},

publisher = {Nippon Bunseki Kagakkai},

abstract = {A review is given on applications of Teflon AF-2400 (refractive index 1.29) liq. core waveguides in spectrophotometric anal., fluorescence/luminescence spectroscopic anal., and Raman spectroscopic anal. [on SciFinder(R)]},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Li2001,

title = {A High-Efficiency Cross-Flow Micronebulizer Interface for Capillary Electrophoresis and Inductively Coupled Plasma Mass Spectrometry.},

author = {Li, Jinxiang and Umemura, Tomonari and Odake, Tamao and Tsunoda, Kin-ichi.},

doi = {10.1021/ac010595w},

issn = {0003-2700},

year  = {2001},

date = {2001-01-01},

journal = {Analytical Chemistry},

volume = {73},

number = {24},

pages = {5992--5999},

publisher = {American Chemical Society},

abstract = {A pneumatic nebulizer interface for capillary electrophoresis (CE) and inductively coupled plasma mass spectrometry (ICPMS) is reported. The interface is constructed using a high-efficiency cross-flow micronebulizer (HECFMN) and has the following features. (1) Makeup solns. can be fed to the interface by nebulizer self-aspiration and liq. gravity pressurization. (2) The liq. dead vol. of the interface is ∼65 nL, much smaller than those (200-2500 nL) reported for other interfaces. (3) The interface can be stably operated at a liq. flow rate down to 5 $mu$L/min with a high analyte transport efficiency up to 95% to the plasma and (4) does not induce noticeable laminar flow in the CE capillary at typical nebulizer gas flow rates of 0.8-1.2 L/min. Because of these features, baseline resoln. of 10 lanthanides with a CE-ICPMS system using the HECFMN interface is achieved, and detection limits and peak asymmetry are 0.05-1 $mu$g/L and 0.93-1.23, resp., improved significantly over those reported previously for a CE-ICPMS system using a high-efficiency nebulizer interface. Peak precision for the 10 lanthanides is at 6.2-12.3% relative std. deviation (N = 5). Peak widths are from 9.1 s for 139La to 17.9 s for 175Lu. The effects of nebulizer gas flow rate, makeup soln. flow rate, and spray chamber vol. on CE-ICPMS signal intensity and sepn. are also evaluated for the HECFMN interface by the sepn. of Cr3+ and Cr2O72-. [on SciFinder(R)]},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Li2001a,

title = {A High-Efficiency Cross-Flow Micronebulizer for Inductively Coupled Plasma Mass Spectrometry.},

author = {Li, Jinxiang and Umemura, Tomonari and Odake, Tamao and Tsunoda, Kin-ichi.},

doi = {10.1021/ac001282o},

issn = {0003-2700},

year  = {2001},

date = {2001-01-01},

journal = {Analytical Chemistry},

volume = {73},

number = {7},

pages = {1416--1424},

publisher = {American Chemical Society},

abstract = {A pneumatically driven, high-efficiency cross-flow micronebulizer (HECFMN) is introduced for inductively coupled plasma (ICP) spectrometries. The HECFMN uses a smaller nozzle orifice for nebulizer gas (75 $mu$m in diam.) and a replaceable and adjustable fused-silica capillary for sample uptake. The HECFMN is optimally operated over a wide range of sample uptake rate (5-120 $mu$L/min) at a radiofrequency power of 1100 W and nebulizer gas flow rates of 0.8-1.0 L/min when a 50 $mu$m internal diam. by 150 $mu$m o.d. capillary is used. The aerosol quality is qual. examd. in a simple manner, and the transport efficiencies are detd. by direct filter collection. Compared with conventional cross-flow nebulizers (CFNs), the HECFMN produces much smaller and more uniform droplets and thus provides much higher analyte transport efficiencies (generally 24-95%) at the sample uptake rates of 5-100 $mu$L/min. Several anal. performance indexes are acquired using an Ar ICPMS system. The sensitivities and detection limits measured with the HECFMN at 50 $mu$L/min sample uptake rate are comparable to or improved over those obtained with a conventional CFN consuming 1 mL/min sample, and the precisions with the HECFMN (typically 1.1-1.7% RSDs) are slightly better than those with the CFN (1.6-2.3% RSDs). The ratios of refractory oxide ion-to-singly charged ion (CeO+/Ce+) are typically at 0.7-3.3% for the sample uptake rates of 5-100 $mu$L/min. The free aspiration rate of the HECFMN is 8.9 $mu$L/min for distd. deionized water at the nebulizer gas flow rate of 1.0 L/min without any effect of pressure. The features of the HECFMN suggest good potential for HECFMN use in interfacing ICPMS with capillary electrophoresis and microcolumn HPLC. [on SciFinder(R)]},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Inagaki2000,

title = {Speciation of trace elements, binding and non-binding with proteins in human blood serum, by surfactant-mediated HPLC with element-selective detection by ICP-MS.},

author = {Inagaki, Kazumi and Umemura, Tomonari and Matsuura, Hirotaka and Haraguchi, Hiroki.},

doi = {10.2116/analsci.16.787},

issn = {0910-6340},

year  = {2000},

date = {2000-01-01},

journal = {Analytical Sciences},

volume = {16},

number = {8},

pages = {787--788},

publisher = {Japan Society for Analytical Chemistry},

abstract = {In the present surfactant-mediated HPLC/ICP-MS system, valuable information about the bindings of trace elements with serum proteins as well as about the existences of small mol. species could be obtained simultaneously, although sepn. selectivity for large-mol. species is poor because of the characteristics of the restricted access-type size exclusion of the surfactant-mediated column. However, it should be stressed here that the quantification of the distributions of trace elements existing as large-mol. and small-mol. species often provides important information in the biomedical study on trace elements. Indeed, for example, free iodide ion in human serum was used as the index of iodine-deficiency in a human body." In consequence, it is concluded that the present surfactant-mediated HPLC/ICP-MS system with element-selective detection may be helpful to obtain the information about trace elements binding and non-binding with proteins in blood serum and other biol. fluids. [on SciFinder(R)]},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Tsunoda2000,

title = {Lock-in modulation detection for a difference interferometric slab optical-waveguide refractive-index sensor.},

author = {Tsunoda, Kin-Ichi and Umemura, Tomonari and Aizawa, Katsuyuki and Takahashi, Yoshito and Odake, Tamao.},

doi = {10.2116/analsci.16.771},

issn = {0910-6340},

year  = {2000},

date = {2000-01-01},

journal = {Analytical Sciences},

volume = {16},

number = {7},

pages = {771--773},

publisher = {Japan Society for Analytical Chemistry},

abstract = {A lock in modulation detection system was applied for a difference interferometric slab optical-waveguide refractive-index sensor. This system has a simple setup and is easy to operate and optimize the measurement conditions. Moreover, it will be applicable to automated measurement. [on SciFinder(R)]},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Umemura1999,

title = {Characteristic conversion of ion pairs among anions and cations for determination of anions in electrostatic ion chromatography using water as a mobile phase.},

author = {Umemura, Tomonari and Kamiya, Shinji and Haraguchi, Hiroki.},

doi = {10.1016/S0003-2670(98)00627-8},

issn = {0003-2670},

year  = {1999},

date = {1999-01-01},

journal = {Analytica Chimica Acta},

volume = {379},

number = {1-2},

pages = {23--32},

publisher = {Elsevier Science B.V.},

abstract = {The peculiar ion pairing elution behavior of anions with cations in electrostatic ion chromatog. with H2O as eluent was studied by using detectors based on cond. and inductively coupled plasma-at. emission spectrometry, where a sulfobetaine-type amphoteric surfactant (C14SB) immobilized on an octadecyl silica surface was employed as the stationary phase. Some preferential combinations of anions with cations were exptl. identified; Mg2+, for example, was preferentially paired with the anions in the order NO3->Br->NO2->Cl->SO42-. The preferential combination characteristics could be used for the control of ion pair formation of analyte anions with countercations. When MgSO4, used here as a decoy electrolyte, in which Mg2+ and SO42- were the decoy cation and decoy anion, resp., was added to the original sample soln. (Cl-, NO2-, Br- and NO3- as analyte anions; Na+ K+, Mg2+ and Ca2+ as countercations) at a relatively high concn. compared to the concns. of analyte anions, all the analyte anions in the sample soln. were eluted with the introduced decoy cation (Mg2+), following the preferential combination. Consequently, all the analyte anions were practically sepd. as a decoy cation form, and they could easily be detd. from the calibration graphs of the anions in the decoy cation salts by cond. detection. The present ion chromatog. method involving the characteristic anion-cation recombination technique was applied to the detn. of (Cl-, Br-, and NO3-) in a vegetable (radish). [on SciFinder(R)]},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Umemura1998,

title = {Direct injection determination of theophylline and caffeine in blood serum by high-performance liquid chromatography using an ODS column coated with a zwitterionic bile acid derivative.},

author = {Umemura, Tomonari and Inagaki, Kazumi.},

doi = {10.1039/a803153c},

issn = {0003-2654},

year  = {1998},

date = {1998-01-01},

journal = {Analyst (Cambridge, United Kingdom)},

volume = {123},

number = {8},

pages = {1767--1770},

publisher = {Royal Society of Chemistry},

abstract = {An ODS column dynamically coated with zwitterionic bile acid deriv., 3-[(3-cholamidopropyl)-dimethylammonio]-1-propanesulfonate (CHAPS), was evaluated for direct injection detn. of drugs in blood serum by HPLC. Polar functional groups such as sulfonate, ammonium and the three hydroxyl groups in CHAPS protruding towards an aq. mobile phase formed a hydrophilic layer over the ODS reversed-phase surface, which resulted in high mol. mass compds. such as proteins being prevented from penetrating into the internal hydrophobic region. The bulk of the proteins were eluted as an unretained or nearly unretained band by using 0.2 mM sodium hydrogenphosphate soln. (pH 7.4) as the mobile phase. In contrast, small mols. such as some inorg. anions and arom. compds. were retained and thereby sepd. from one another. It was confirmed that the ODS column modified with CHAPS acts as a restricted access-type column with a hydrophobic interior and a hydrophilic exterior. Hence biol. fluids could be directly injected into the CHAPS-coated ODS column. The present HPLC system using the CHAPS-coated ODS column was applied to the detn. of theophylline and caffeine in human blood serum. The detection limits for the two drugs with UV absorption at 273 nm were 0.2 and 0.5 mg L-1 (injection vol. 20 $mu$L) and the relative std. deviations of peak area measurements were <1.4% and 2.2%, resp., for 10 replicate measurements of serum spiked with 5 mg L-1 of each of the drugs. [on SciFinder(R)]},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Umemura1998a,

title = {Counterionic Detection by ICP-AES for Determination of Inorganic Anions in Water Elution Ion Chromatography Using a Zwitterionic Stationary Phase.},

author = {Umemura, Tomonari and Kitaguchi, Ryuji and Haraguchi, Hiroki.},

doi = {10.1021/AC970894E},

issn = {0003-2700},

year  = {1998},

date = {1998-01-01},

journal = {Analytical Chemistry},

volume = {70},

number = {5},

pages = {936--942},

publisher = {American Chemical Society},

abstract = {The anal. methods for the detn. of inorg. anions by water elution ion chromatog. using a zwitterionic column (C14SB-coated column) were explored, where pure water was used as the mobile phase. In the present ion chromatog., the complicated peaks derived from various ion pairs appeared on the chromatogram when the sample soln. contained several kinds of cations and anions. The chromatograms with the complicated peaks were simplified by using a preconditioning cation-exchange column. In the preconditioning column, various kinds of countercations of the analyte anions were converted to a particular kind of common cation, and thus all the analyte anions were sepd. as the common cation form. The more effective sepn. was achieved by converting to a divalent cation (Mg2+) form than a monovalent cation (Na+) form, because the anions paired with the divalent cation provided longer elution times than those paired with the monovalent cation. All the analyte anions sepd. as the common cation form were simply detd. from their calibration curves drawn from cond. detection. The counterionic detn. of the anions was also attempted by using ICP-AES. The analyte anions were detd. by measuring their countercations with ICP-AES, where the calibration curve of the countercation measured by ICP-AES could be used. [on SciFinder(R)]},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Umemura1997,

title = {Evaluation of sulfobetaine-type zwitterionic stationary phases for ion chromatographic separation using water as a mobile phase.},

author = {Umemura, Tomonari and Kamiya, Shinji and Itoh, Akihide and Chiba, Koichi and Haraguchi, Hiroki.},

doi = {10.1016/S0003-2670(97)00222-5},

issn = {0003-2670},

year  = {1997},

date = {1997-01-01},

journal = {Analytica Chimica Acta},

volume = {349},

number = {1-3},

pages = {231--238},

publisher = {Elsevier},

abstract = {Ion chromatog. sepn. of inorg. ions (anions and cations) was studied by using three kinds of sulfobetaine-type surfactants (CHAPS, C12SB, and C14SB) as the stationary phases, which were coated by hydrophobic adsorption on the ODS column. In the present sepn. system, pure H2O was used as a mobile phase. Since the amt. of surfactant adsorbed on the ODS surface significantly influenced the retention behaviors of inorg. ions, the amts. of the sulfobetaine-type surfactants adsorbed were estd. by the breakthrough procedure. The max. amts. of CHAPS, C12SB and C14SB adsorbed were 0.40, 0.87 and 1.08 mmol, resp. It was elucidated from the chromatograms of inorg. ions that the retention behavior of inorg. anions was directly related to the surface charges arising from the adsorbed surfactants. The large surface charge was effective for the efficient sepn. of inorg. ions in H2O elution. Their retention behavior was strongly affected by the hydrophobicity of the adsorbed surfactants as well as the ionic functional groups of the surfactants which produced the charged surface. The elution order of inorg. anions was correlated with the Hofmeister series. Probably the hydration energies of the ions play important roles in sepn. in the H2O elution system. [on SciFinder(R)]},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Umemura1997a,

title = {Partitioning of cations and anions of electrolytes in electrostatic ion chromatography using pure water as mobile phase.},

author = {Umemura, Tomonari and Kamiya, Shinji and Kitaguchi, Ryuji and Haraguchi, Hiroki.},

doi = {10.1246/cl.1997.755},

issn = {0366-7022},

year  = {1997},

date = {1997-01-01},

journal = {Chemistry Letters},

number = {8},

pages = {755--756},

publisher = {Chemical Society of Japan},

abstract = {The elution behaviors of the mixt. soln. of strong electrolytes in electrostatic ion chromatog., using pure water as a mobile phase, were studied with a cond. detector and ICP-AES, where a zwitterionic surfactant adsorbed on an ODS column was used as a stationary phase. The characteristic re-combinations of cations and anions as the ion-pairs were obsd. in the chromatograms. [on SciFinder(R)]},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Hu1997,

title = {A novel ion chromatographic method using zwitterionic surfactants as the stationary phase and water as the mobile phase.},

author = {Hu, Wenzhi and Hasebe, Kiyoshi and Reynolds, Darren Michael and Umemura, Tomonari and Kamiya, Shinji and Itoh, Akihide and Haraguchi, Hiroki.},

doi = {10.1080/10826079708005551},

issn = {1082-6076},

year  = {1997},

date = {1997-01-01},

journal = {Journal of Liquid Chromatography & Related Technologies},

volume = {20},

number = {12},

pages = {1903--1919},

publisher = {Dekker},

abstract = {Zwitterionic surfactants immobilized on the surfaces of octadecylsilica (ODS) are used for the stationary phase and water as the mobile phase for the ion chromatog. (IC) of target analytes. The creation of an elec. double layer (EDL), when a zwitterionic stationary phase is in contact with the analyte ions, is proposed to explain the sepn. mechanism. When an EDL is created using a zwitterionic stationary phase (ZWEDL), its properties differ considerably to those of a single charge-fixed stationary phase created EDL. For a ZWEDL, (i) the electrostatic field is increased, resulting in the simultaneous retention and sepn. of both cations and anions; (ii) the electrostatic affinity between the analytes in the ZWEDL and the stationary phase is extremely weak. This results in the effective distribution of the analytes between the stationary phase and the mobile phase without the need for ion-exchange. Since only water is used for the mobile phase, the sensitivity of detection by cond. is vastly improved and the direct detn. (without pre-concn.) of inorg. ions at ultra low levels is possible. Also, since both pos. and neg. electrostatic fields are produced simultaneously, both analyte cations and anions are retained and sepd. in a single stage of the stationary phase. This provides the basis for a simple and rapid chromatog. method for the simultaneous anal. of cations and anions. [on SciFinder(R)]},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Hu1995a,

title = {Direct Determination of Inorganic Ions at Sub-ppb Levels by Ion Chromatography Using Water as a Mobile Phase.},

author = {Hu, Wenzhi and Tominaga, Mamoru and Tao, Hiroaki and Itoh, Akihide and Umemura, Tomonari and Haraguchi, Hiroki.},

doi = {10.1021/ac00116a015},

issn = {0003-2700},

year  = {1995},

date = {1995-01-01},

journal = {Analytical Chemistry},

volume = {67},

number = {20},

pages = {3713--3716},

publisher = {American Chemical Society},

abstract = {Electrostatic ion chromatog. (EIC) was used for detn. of trace level inorg. ions. EIC is a new method of sepg. ions based on simultaneous electrostatic attraction and repulsion interactions between analyte ions and fixed pos./neg. charges of a stationary phase, having the special advantage of using only water as the mobile phase. Initial results showing two elutions of the same analyte gave new insights into the mechanism of EIC. Probably the zwitterionic stationary phase, like a single charged stationary phase, has a Stern layer and a diffuse layer. The 1st elution is from the diffuse layer and the 2nd is from the Stern layer. As simpler anal. is facilitated by a single elution, a new species of inorg. salt with a longer elution time was added to the original sample soln. to release analyte ions from the Stern layer to the diffuse layer. The newly introduced salt is called a sacrifice species. Without preconcn., inorg. ions at sub-ppb levels were successfully detected by this method. [on SciFinder(R)]},

keywords = {},

pubstate = {published},

tppubtype = {article}

}