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Cations on Ion Chromatography by Phosphate-Coated Zirconia Stationary Phase Column

Mori M., Masuno T., Kozaki D., Nakatani N., Tanaka K., Itabashi H.

Acta Chromatographica

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2015

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Vol. 27, no. 4

767--773

EN

Ion chromatography of inorganic cations using a phosphate-coated zirconia stationary phase (PZ) was first attempted. The retentions of cations to PZ increased by elevating the column temperature and the reproducibility of the separation could improve at the higher temperature. The PZ functioned as a cation-exchanger from changes in the retention factor of cations as a function of eluent pH. Furthermore, the Gibbs free energies of cations were estimated from enthalpy and entropy using the retention factors of cations as a function of the column temperature. The reaction was based on the endothermic reaction.

2

Effect of perfluorinated surfactant as additive of background electrolyte for capillary electrophoresis of inorganic cations

Mori M., Ikeda T., Itabashi H.

Acta Chromatographica

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2012

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Vol. 24, no. 4

529--542

EN

This study reports the effect of a nonionic perfluorinated surfactant, N-polyoxyethylene-N-propyl perfluorooctane sulfonamide (PFOSA), as additive of background electrolyte on capillary electrophoresis (CE) of common inorganic cations. The association constants (Kass) for PFOSA estimated from the electrophoretic mobility of analyte cations were the order of Mg2+ > Ca2+ > Sr2+ > K+ ≈ NH4+ > Na+ ≈ Li+. The Kass values were larger than those for zwitterionic and nonionic surfactants with hydrocarbon moiety. Use of PFOSA made another essential contribution to the determination of inorganic cations in a protein-containing sample. This was considered because high solubility of PFOSA for proteins functioned as suppressor for protein adsorption to the capillary wall. Four inorganic cations, Na+, K+, Mg2+, and Ca2+, in human saliva sample were successfully determined by sample injection without any pretreatments except for filtration and dilution.

3

Use of an amphiphilic calix[4]arene with sulfonate functionality at the lower rim as a buffer additive in capillary electrophoresis

Mori M., Hirayama A., Tsue H., Tanaka S.

Acta Chromatographica

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2007

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No. 19

73-80

EN

An amphiphilic calix[4]arene with sulfonate groups on the lower rim has been investigated as a buffer additive for separation of positional isomers by capillary electrophoresis. Addition of the compound to the run-ning buffer led to successful separation of positional isomers of nitrophenols, dinitrobenzenes, and benzenediols. Association constants between the calixarene and the analytes indicated that size-selective host–guest inter-actions between them played a prominent role in determining the separation behavior.

4

Use of combined ion-exclusion and cation-exchange chromatography to study photooxidation of ionic nitrogen compounds on a titanium dioxide photocatalyst

Mori M., Taoda H., Itabashi H., Ikedo M., Tanaka K.

Acta Chromatographica

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2006

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No. 16

28-37

EN

Combined ion-exclusion and cation-exchange chromatography (IEC/CEC) on a weakly acidic cation-exchange resin in the H+-form (TSKgel Super IC-A/C) has been used as an advanced method for evaluation of the photooxidation of ionic nitrogen compounds, for example triethanolamine, trimethylamine, and urea, on a TiO2 photocatalyst. Formation of NH4+ and NO3- from each nitrogen compound by photooxidation on the catalyst du-ring UV irradiation was successfully monitored by use of IEC/CEC under optimized mobile-phase conditions (6 mM tartaric acid and 3 mM 18-crown-6). It was found that the products formed depended on whether or not a mole-cule contained a hydroxylated nitrogen moiety or other hydroxyl group.

5

Modeling of ion-exclusion and vacancy ion-exclusion chromatography on a strongly acidic cation-exchange resin in the H+ form

Kaczmarski K., Mori M., Głód B., Kowalska T., Tanaka K.

Acta Chromatographica

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2005

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No. 15

66-81

EN

Ion-exclusion chromatography (IEC) can sometimes be used for se-paration of the weak acids using pure water as mobile phase. Characteristic leading (i.e. frontally tailing) peaks are obtained and retention depends on the concentration of solutes. It was recently shown that this order could be reversed. In vacant ion exclusion chromatography (vIEC) sample flows as mobile phase and pure water is injected as the sample. Symmetrical peaks are obtained; this is believed to be because of self-buffering of the solutes in the sample. The aim of the work discussed in this paper was to describe the mechanism of retention in IEC and vIEC by using the modified equi-librium–dispersive (ED) model. It was found that the retention times and peak shapes predicted by the derived equations are in good agreement with experimental data. These equations also predict new features of vIEC, and these were confirmed experimentally. It was shown that in vIEC, in con-trast with IEC, symmetrical peaks are obtained even for a single analyte.

6

Ion chromatography of common anions by use of a reversed-phase column dynamically coated with fluorine-containing surfactant

Helaleh M. I. H., Al-Omair A., Tanaka K., Mori M.

Acta Chromatographica

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2005

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No. 15

247-257

EN

A method with unusual selectivity has been developed for determi-nation of common anions such as chloride, bromide, nitrite, sulfate, phosphate, and iodide. The method uses with reversed-phase columns (graphite carbon and ODS), coated with fluorine-containing surfactant, and conductivity detection. A graphitized carbon column was selected for this study because of its high chemical stability, reliability, and reproducibility. Separation of common anions was achieved in 12 min. Calibration plots of peak area against anion concentrations were linear in the range 1–15 µg mL-1 for Cl-, 1–20 µg mL-1 for Br- and SO42-, and 3–20 µg mL-1 for I- and NO3-, with good correlation coefficients (r2 = 0.9922). Detection limits calculated for a signal-to-noise ratio (S/N) of 3 ranged from 0.76 to 0.98 µg mL-1. The reproducibility of retention times was varied from 0.28 to 0.45 relative standard deviation (RSD,%) and reproducibility of chromatographic peak areas was 2.13–3.25 (RSD,%).The method was successfully applied to the determination of anions in acid rain and related natural waters, including rain, river, and underground water.

7

Low frequency of spontaneous rearrangements during plasmid incorporation in CHO-K1 mutant cells defective in DNA repair

Kruszewski M., Kruszewska H., Mori M., Eguchi-Kasai K., Inaba H., Zakierska I., Hayata I.

Nukleonika

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2002

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Vol. 47, nr 1

7-11

EN

pLrec plasmid DNA was introduced into Chinese hamster cell lines defective in DNA repair (Pa13, Pb4, xrs6) and the parental CHO-K1 cell line. Clones with stable integrated plasmid were isolated and integrity of the incorporated DNA was checked by Southern blotting and PCR. Intact pLrec plasmid was found in 11% of the isolated CHO-K1 clones. In contrast, intact plasmid copies were found in 68.8%, 50%, 35.7% clones of Pa13, Pb4 and xrs6 cell lines, respectively. We conclude that certain DNA repair defects may facilitate intact plasmid integration. The higher frequency of integration of the intact vector into the genome of cell lines defective in DNA repair as compared to the parental cell line points to two possibilities, not mutually exclusive: (1) these cells possess a mechanism that facilitates the process of plasmid incorporation and hence, plasmid DNA is incorporated into the genome before extrachromosomal recombination takes place; (2) the vector is inserted into a less recombination prone site in the genome.

8

Semi-analytical sensitivity analysis procedure for frictional contact problems

Chen X., Hisaida T., Nakamura K., Mori M.

Computer Assisted Mechanics and Engineering Sciences

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2000

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Vol. 7, No. 1

69-80

EN

Although there is a need for sensitivity analysis for frictional contact problems in many engineering fields, research work on it has rarely been reported due to the complexity of the problems. In this paper, a sensitivity analysis procedure based on a semi-analytical method for frictional contact problems is presented. The unbalance force due to the variation of design parameters is evaluated numerically, thus the related routine of an existing FEM code can be utilized regardless of the friction law employed. The continuum-mechanics-based formulation is carried out first and then a discretized form is derived. The stick state is modeled by introducing a penalty-type constraint. A couple of numerical examples, including a realistic leaf spring structure used in nuclear power plants, are given to demonstrate the effectiveness of the proposed approach.

9

Finite element analysis for multi-leaf structures with frictional contact and large deformation

Chen X., Nakamura K., Mori M., Hisaida T.

Computer Assisted Mechanics and Engineering Sciences

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2000

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Vol. 7, No. 1

53-67

EN

The analysis of multi-leaf structures should be performed taking friction into account. The objectivity of friction law should be preserved because large deformation generally occurs. By use of the convected coordinate system, the objectivity can be preserved naturally. Therefore, in finite element analysis, the element local coordinate system can be used. However, when a contact point slides over the element boundary, a problem arises due to the discontinuity of the local coordinates between elements. In this work, an algorithm is proposed, i.e., the formulation is essentially based on the convected coordinate system while the sliding term is redefined as a spatial vector and is calculated in the reference configuration. Thus, the finite sliding due to large deformation can be treated without paying special attention to the limit of the local coordinate system. Two numerical examples including a simplified model of a leaf spring structure used in nuclear power plants are given.