• Journal of the Korean Chemical Society
• /
• v.30 no.1
• /
• pp.63-68
• /
• 1986

Elution behavior of rare earth elements have been investigated with the EDTA solution as an eluent using cation exchange resin. Definite amount of the complexed rare earth ions at pH 8.4 is adsorbed through the cation exchanger containing cupric ion as a retaining ion and eluted with EDTA solution. The rare earth ions are eluted more rapidly in the above method than in the method in which uncomplexed rare earth ions are adsorbed on the cation exchange resin bed. In this method, the elution time and amount of eluent are saved but the resolution values also decreased a little. The elution order of complexed ion was determined in accordance with the stability constant of complexes with rare earth elements.

• Journal of the Korean Chemical Society
• /
• v.36 no.5
• /
• pp.692-696
• /
• 1992

$NH_4^+ form cation exchange resin was used to separate one rare earth element from the rare earth mixture solution using Ln-EDTA eluent. Rare earth mixture solution was passed through the resin bed and eluted with 0.1M La-EDTA solution as an eluent. In here all the rare earth element except lanthanum ion are eluted and lanthanum ion absorbed in resin bed is eluted using 0.1M EDTA solution. If Ce-EDTA solution instead of La-EDTA solution was used as an eluent, all the rare earth element except cerium ion are eluted and cerium ion is eluted with 0.1M EDTA solution. This method can be applied to separate the individual rare earth element from the mixture. The separation mechanism is as follows: Absorption : 3RNH_4 ＋ Ln^{3+} = R_3Ln ＋ 3NH_4^+, La-EDTA elution : R_3Ln ＋ La-Y- = R_3La ＋ Ln-Y-, EDTA elution : R_3La ＋ HY^3- = La_-Y ＋ RH ＋ 2R^-.$

• Journal of the Korean Chemical Society
• /
• v.31 no.1
• /
• pp.31-36
• /
• 1987

We examined eluting behaviors for cationic complexes with the eluting cations. Retention volumes of hydrophilic complexes when eluted by the high concentration of aqueous KCl, NaCl and $NH_4Cl solutions, have been increased in the order NH_4^+ > Na^+ > K^+$, but in the low concentration, retention volumes of hydrophilic complexes bave been increased in the order $Na^+ > NH4^+ > K^+$. On the order hand, retention volumes of hydrophobic complexes when eluted by aqueous KCl, NaCl and $NH_4Cl solutions, have been increased in the order NH_4^+ > Na^+ > K^+$ in the whole concentration range. And we examined eluting behaviors for cationic complexes with the eluting anions. Hydrophilic complexes were associated more strongly with chloride ion among halide ions. However, hydrophobic complexes were associated more strongly with iodide ion. Sulfate ion, a highly hydrated anion, was associated more strongly with hydrophilic complexes than with hydrophobic complexes.

• Analytical Science and Technology
• /
• v.10 no.1
• /
• pp.53-59
• /
• 1997

Chloride form anion exchange resin was used to separate one of the elements from the rare earth mixture using respectable Ln-EDTA eluent. $Sm^{3+}$, $La^{3+}$ or $Ce^{4+}$ complexed with EDTA was passed through the resin column and eluted with a Sm-EDTA solution as an eluent. Here all the rare earth element ions except $Sm^{3+}$ were passed. Adsorbed $Sm^{3+}$ in resin was eluted with 1.0 M HCl solution. If La-EDTA solution as an eluent was used to separate lanthanum ions, lanthanum ions were eluted together with other rare earth elements. When Ce-EDTA solution was also used for separation of $Ce^{4+}$, it was eluted in the region of other rare earth elements. In the case of Sm-EDTA elution, the elution mechanism was as follows : Absorption : $RCl+Ln-Y^-{\leftrightarrows}RLnY+Cl^-$, Sm-EDTA elution : $RLnY+Sm-Y^-{\leftrightarrows}RSmY+Ln-Y^-$, HCl elution : $RSmY+HCl{\leftrightarrows}RCl+Sm-Y^-$.

• Analytical Science and Technology
• /
• v.5 no.1
• /
• pp.63-71
• /
• 1992

Liquid chromatographic behavior of Pd(II), Ni(II) and Co(III) in N-Alkylisonitrosoacetylacetone imine(HIAA-NR) chelates was investigated by reversed phase high perfomance liquid chromatography. The optimum conditions for the separation of IAA-NR-metal chelates were examined respect to the flow rate and mobile phase strength. The metal-N-Alkylisonitrosoacetylacetone imine chelates in solution were successfully separated on Novapak $C_{18}$ column using acetonitrile/water mixture as mobile phase. The elution order of chelates is methyl>ethyl>propyl>butyl as N-alkyl group for ligand is varied. It was found that all IAA-NR-metal chelates were eluted in an acceptable range of capacity factor value($0{\leq}log\;k^{\prime}{\leq}1$). The dependence of log k' on the volume fraction of water in the binary mobile phase was examined. Also, the dependence of k' on the liquid-liquid extraction distribution ratio(Dc) in acetonitrile-water-alkane extraction system was investigated for IAA-NR-metal chelate. Both kinds of dependence are linear, which suggests that the retention of the electroneutral metal chelates on Novapak $C_{18}$ column is largely due to the hydrophobic effect.

• Journal of the Korean Chemical Society
• /
• v.39 no.5
• /
• pp.379-383
• /
• 1995

The elution behaviors of stannous ion by PSA(phenol sulfonic acid) as an eluent on chelating resin, Amberlite IRC-718 have been investigated. When 0.10 M stannous solution was adsorbed on the resin and eluted with various concentrations of PSA, the two peaks of stannous ion were appeared in the elution curve. These two peak areas were changed according to the PSA concentration. Using these results, the stability constant of the complex formation between Sn2+ and PSA was calculated. This value is 2.0 ${\times}$ 10-1.

• Journal of the Korean Chemical Society
• /
• v.29 no.2
• /
• pp.183-190
• /
• 1985

The elution behaviors of the rare earths was carried out in the iminodiacetic acid solution of various pH as eluent using ion exchange resin. The optimum eluent for the quantitative separation of $Eu^{3+},\;Pr^{3+},\;Ce^{3+}\;and\;La^{3+}$ were 0.0301M IMDA solution of pH 8.00 and 9.00 at 5cm column of the resin Dowex 50${\times}$8 (100-200 mesh). The elution order of the rare earth elements was in order of the atomic number of those elements. From the elution behavior of rare earth and u.v spectrum we found that the complexed rare earth species with IMDA changed according to pH of IMDA.

• Journal of the korean academy of Pediatric Dentistry
• /
• v.35 no.3
• /
• pp.477-486
• /
• 2008

Acrylic resin is widely used in dental practice. However, the residual monomer in acrylic resin could act as a negative biocompatability on human body. The aim of this study was to evaluate the amount of the monomer elution from polymerized orthodontic acrylic resin. Orthodontic acrylic resin was used in the study. The curing condition of the resin was controlled by temperature, pressure, aquatic and atmospheric environment. The duration and amount of monomer elution and timedependent plot was recorded by high performance liquid chromatography. The result showed that the only monomer eluted from the resin was methyl methacrylic acid. And the amount of the monomer elution has diminished considerably by time progress especially within 24 hours. Furthermore, elution of the residual monomer was significantly lower in group of pressure, moisture and elevated temperature than control (p<.05). According to this study, it was thought that the elution of residual monomer might be influenced by curing environment.

• Journal of the Korean Chemical Society
• /
• v.24 no.6
• /
• pp.452-456
• /
• 1980

An anion exchange method for separating Y, La, Ce, Pr, and Nd element in monazites and into enriched fractions has been developed. The complexed rare earth ions with EDTA at pH 8.4 passed through the resin column of the various size and eluted with 0.0301 M EDTA as eluent at flow rate of 1 ml/min and 2 ml/min. The result of separation is good in the high column length rather than the low on using the resin of the same amount and the volume of eluent required in eluting all the rare earths at 2 ml/min flow rate is larger than that at 1 ml/min and the result of separation obtained here is unsatisfactory.

• Journal of the korean academy of Pediatric Dentistry
• /
• v.32 no.2
• /
• pp.284-292
• /
• 2005

The aim of this study was to identify and quantify the major or detectable monomers released from any of five commercially-available, light-cured pit and fissure sealants with three different light sources : conventional halogen light curing unit, plasma arc light curing unit and LED curing unit. After curing, specimens were immediately immersed in distilled water for different time intervals. The time related release of monomers were analyzed by high performance liquid chromatography(HPLC). Identification and quantitative analysis of monomers were performed by the comparison of the elution time and the absorption peak height of the eluates with those of the authentic sample. The result of this study can be summarized as follows. 1. Standard solution peaks with retention times of 2.3, 3.2, 5.6, 6.5, 10.4 minutes were identified as BPA, TEGDMA, UDMA, Bis-GMA, Bis-DMA, respectively. 2. None of the chromatograms of the tested sealants displayed peaks with the same retention time as that of the standard solution, except for TEGDMA. 3. The highest release rate of TEGDMA was observed during the 12hr period for all samples and declined thereafter. 4. The elution of TEGDMA from curing with Halogen curing unit for 20 second and LED for 10 second was less than that resulting from curing with Plasma arc for 3 second. 5. TEGDMA was detected at much lower levels in eluates from the Pit & Fissure $Sealant^{TM}$ than other sealants. The elution of TEGDMA from the $Helioseal^{(R)}$ F cured with Halogen light curing unit, the $Concise^{TM}$ cured with Plasma arc curing unit and the $Teethmate^{(R)}$ F-1 cured with LED curing unit were higher than other sealants.