• Journal of the Korean Chemical Society
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• v.45 no.3
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• pp.219-222
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• 2001

Separation of lithium isotopes was investigated by chemical ion exchange with a hydrous manganese(IV) oxide ion exchanger using an elution chromatography. The capacity of manganese(IV) oxide ion exchanger was 0.5 meq/g. The heavier lithium isotope was enriched in the solution phase, while the lighter isotope was enriched in the ion exchanger phase. The separation factor was determined according to the method of Glueckauf from the elution curve and isotopic assays. The separation factor of $^6Li^+$-$^7Li^+$ isotope pair fractionation was 1.018.

• Journal of the Korean Chemical Society
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• v.28 no.1
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• pp.47-53
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• 1984

The separation of the rare earth elements with diethylene triamine N, N, N', N', N"-pentaacetic acid (DTPA) as eluent was carried out at different pH and concentrations by using anion exchange resin column. The rare earth elements were absorbed on the upper of the resin column and the best condition of the separation behavior was 0.025M of DTPA at pH 8.35. The elution order of the rare earths was in the order of the atomic number of the rare earth elements except samarium. The resolution of adjacent rare earth elements that have been separated with 0.025M-DTPA as eluent, was from 3.03 to 1.25 at pH 8.35. Resolution of Ce-Pr was maximum value in 3.03 and Eu-Gd was minimum in 1.25 at condition mentioned above, respectively. The resolution of rare earth elements separated with 0.025M DTPA eluent was very good at pH range of 8.0~8.6.

• Korean Journal of Medicinal Crop Science
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• v.9 no.1
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• pp.21-25
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• 2001

Major saponins in ginseng were analysed using reverse phase high performance liquid chromatography with binary mobile phase gradient control system instead of normal phase column. The optimum condition were as following : reverse phase column; ${\mu}{\beta}ondapak\;C_{18}$ column (Waters, $3.9mm{\times}300\;mm,\;5{\mu}m$), methyl cyanaide/water binary mobile phase gradient control system, solvent flow rate; 1.5 ml/min, and UV($203{\mu}m$ ) detector. The complete separation of ginsenoside $Rb_1,\;Rb_2,\;Rc,\;Rd,\;Re,\;Rf\;and\;Rg_1$ was achieved within 55 min. The Regression coefficients of the calibration curves for seven ginsenosides were 0.99.

• Journal of the Korean Chemical Society
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• v.36 no.1
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• pp.57-65
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• 1992

The method for investigating the retention behavior and separation optimization was studied to develop a reversed-phase liquid chromatography of eleven thiocarbamates that are used as herbicides. As an isocratic elution system, the statistical simplex technique was applied to find the optimum separation conditions. The resolution was quantitatively evaluated by using COF and ORM method. For thiocarbamate herbicides in which the elution order varies dramatically with solvent composition, the ORM method gave better result than the COF method. For the solvent composition of mobile phase in the ORM method, the ratio of methanol : acetonitrile : tetrahydrofuran : water was 16 : 29 : 2 : 53. Also in this research, an adjusted COF $(\overline{COF})$ method was proposed to rectify the defect in the current COF method, and the compositional ratio of mobile phase containing methanol : acetonitrile : water was 29.5 : 21.5 : 49.0 result of which is similar to that obtained by the ORM method.

• Journal of the Korean Chemical Society
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• v.41 no.11
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• pp.612-638
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• 1997

The methods of separation and recovery of rare earth elements in monazite sand have been studied by the ion exchange chromatography. Both of cation and anion exchange resin were used as ion exchange resins and the solutions of EDTA, DTPA, IMDA and Ln-EDTA were used as eluents. The H+, Zn2+, Fe3+, Al3+, Cu2+, and NH4+ forms of cation exchange resin were used as retaining ions. Ln-EDTA solution was loaded on the EDTA form of anion exchange resin and separated. The Ln-EDTA solution was also used as an eluent for a selective separation of one element from the rare earth mixture solution. The size effects of resin column, the elution mechanism for the various elution types and the separation of a large amount of rare earths were studied.

• Journal of the Korean Chemical Society
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• v.17 no.6
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• pp.434-438
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• 1973

Distribution coefficients (C) of some transition metal ions such as Ni(II), Cu(II), Cd(II), Zn(II), and Hg(II) have been determined in methanol-, ethanol-, isopropanol-, acetone-, and dimethylsulfoxide-water mixtures by using Rexyn 101 (Na-form) resin and 0.2 M sodium chloride solution. The log C values of the metallic ions decrease almost straightly with the increase in reciprocal values of the dielectric constants of the mixed solvents. In the solvents having the same dielectric constants, the distribution coefficients of the metallic ions decrease with the increase in the basicity of the aprotic organic molecule and with the decrease in the molecular size of the protic organic molecule. The separation of the metallic ions has been accomplished with the eluting agent suggested by the C values.

• Journal of the Korean Chemical Society
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• v.32 no.3
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• pp.211-226
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• 1988

Liquid chromatographic behavior of several metal ions in dithiocarbamate(DTC) chelates were investigated by reversed phase high performance liquid chromatography on Novapak $C_{18}$ and ${\mu}$-Bondapak $C_{18}$ columns. The optimum conditions for the separation of DTC-metal chelate were examined with respect to the pH, shaking time, flow rate, extraction solvent, and mobile phase strength. The metal ions in mixtures at trace level, chelated with some dithiocarbamate derivatives were separated successfully on Novapak $C_{18}$ column using acetonitrile/methanol/water or acetonitril/water mixtures as mobile phases. It was found that all DTC metal chelates studied were eluted in an acceptable range of capacity factor values ($0{\leqq}log\;k'{\leqq}1$). Although several foreign metal ions were coexisted, high recovery and good precision were attained ; 97.0-106.7 % for the recovery and 0.98-3.41% for the coefficient of variation. Under the optimum analytical conditions, trace metal ions in the composite water samples were determined sucessfully with in relative error of about {\pm}$6.7 %.

• Journal of the Korean Chemical Society
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• v.42 no.4
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• pp.416-421
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• 1998

In the reversed-phase ion-pair high performance liquid chromatographic (RPIP-HPLC) elution behavior of noble metal-thiacrown ether complexes, the effects of the concentration of ion-pairing reagent and kind of ligands were studied. It was found that the less the number of atoms in the ring of the thiacrown ether molecule was, the larger the selectivity was, and the elution mechanism of the complexes was explained due to the formation of ion-pair when the concentration of sodium dodecyl sulfate (SDS) in mobile phase was lower than 10 mM and due to the formation of micelle when the SDS concentration was higher than 10 mM. As a conclusion, separations of the noble metal-thiacrown ether complexes in an optimum separation condition were accomplished successfully and the method was proved to be an useful one for the separation and determination of Ag (Ⅰ) ion in a black-white photographic fixing solution.

• 한국해양학회지
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• v.10 no.1
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• pp.33-40
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• 1975

The ion exchange sorption and elution behavior of toxic heavy metal ions, such as Hg(II) and Zn(II), have been studied in aqueous and methanolic media of MCl (M: K, Na and NH$\_$4/). The ion exchange resins studied are Dowex 1-X8, Cl$\^$-/ (50-100 or 200-400 mesh) and Dowex 50W-X8, M$\^$+/ form (M: K, Na, NH$\_$4/ and H). the sorption and elution of metal ion on the resin is largely due to the formation of the anionic chlororocomplex of metal ion. The addition of methanol in the medium contributes markedly to the distribution data. In order to apply this work for the treatment of polluted sea water with toxic heavy metal ions, removal experiment of the metal ions from the synthetic sample solution was investigated.

• Analytical Science and Technology
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• v.5 no.4
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• pp.389-399
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• 1992

Liquid Chromatographic behavior of Pd(II) in Isonitrosoethylacetoacetate lmine, $Pd(IEAA-NR)_2$ (R=H, $CH_3$, $C_2H_5$, $n-C_3H_7$, $C_6H_5-CH_2$, $n-C_4H_9$) chelates were investigated by reversed-phase HPLC on Micropak MCH-5 column using methanol/water as mobile phase. The optimum conditions for the separation of $Pd(IEAA-NR)_2$ chelates were examined with respect to the effect of the flow rate, sample solvent, mobile phase strength and column temperature. It wass found that metal chelates were properly eluted in an acceptable range of capacity factor value($0{\leq}log\;k^{\prime}{\leq}1$). The dependence of the logarithm of capacity factor(k') on the volume fraction of water in the binary mobile phase was examined. Also, the dependence of k' on the liquid-liquid extration distribution ratio($D_c$) in methanol-water/n-alkane extration system was investigated. Both kinds of dependence are linear, which susggests that the retention of the electroneutral metal chelate is largely due to the solvophobic effect. Standard adsorption enthalpy changes (${\Delta}H^{\circ}$) and standard adsorption entropy changes (${\Delta}S^{\circ}$) of Pd(II) Isonitrosoethylacetoacetate imine chelates on Micropak MCH-5 column were calculated by measuring capacity factor with changing temperature of the column.