• Journal of the Korean Chemical Society
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• v.36 no.5
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• pp.697-708
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• 1992

Liquid Chromatographic behavior of Ni(II) in Isonitrosoethylacetoacetate Imine(IEAA-NR), Ni(IEAA-NH)(IEAA-NR)(R = H, CH_3, C-2H_5, n-C_4H_9, C_6H_5-CH_2) 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 Ni(IEAA-NH)(IEAA-NR) chelates were examined with respect to the effect of the flow rate, sample solvent, mobile phase strength and column temperature. It was fo$und that metal chelates were properly eluted in an acceptable range of capacity factor value(0{\le}logk'{\le}1). The dependence of the logarithm of capacity factor (k') on the volume fraction of water in the binary mobile phase as well as on the liquid-liquid extraction distribution ratio (Dc) in methanol-water/n-alkane extraction system showed the good linearties, and the dependence of the logarithm of capacity factor (k') on the column temperature and on the enthalpy exhibited the good linearties, and the compensation temperature ({\beta}) from the slope was 773.47{\circ}K. It was suggested that the retention of metal chelates was largely affected by the hydrophobic effect.

• Korean Chemical Engineering Research
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• v.49 no.3
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• pp.348-351
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• 2011

In this research, we developed a sensor system which can easily detect several chelating agents using polydiacetylene(PDA) vesicles. In comparison to other sensors, PDA based sensor has several advantages. First, detection method is much simpler and faster because it does not require any labeling step in the experiment procedure. Second, significant color-transition from blue to red based upon external stimulus allows us the detection by naked eyes. Finally, it is also possible to perform quantitative analysis of the concentration of the chelating agent by measuring the colorimetric response. In this paper, five types of chelating agents were used, including EDTA, EGTA, NTA, DCTA and DTPA. Among them, EDTA and DCTA triggered especially strong color-transition. In conclusion, this study has led to a successful development of a color transition-based PDA sensor system for easy and rapid detection of chelating agents.

• Current Research on Agriculture and Life Sciences
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• v.32 no.3
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• pp.155-158
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• 2014

Phytoextraction is a technique that uses plants to remediate metal-contaminated soils. However, this technique cannot be applied in highly metal-contaminated areas, as plants cannot normally grow under such conditions. Therefore, this study investigated the introduction of various biodegradable chelating agents to increase the bioavailability of metals in highly metal-contaminated areas. Mercury (Hg) was selected as the target metal, while cysteine (Cys), histidine (His), malate, succinate, oxalate, citrate, and ethylenediamine (EDA) were used as biodegradable chelating agents. Plants were grown on agar media containing various chelating agents and Hg to analyze the effect on plant root growth. Cys and EDA were both found to diminish the inhibitory effect of Hg on plant root growth, whereas His, citrate, and ethylenediamine tetraacetic acid (EDTA) did not show any significant effects, and malate, succinate, and oxalate even promoted the inhibitory effect of Hg on plant root growth. Thus, Cys and EDA would seem to be promising biodegradable chelating agents for highly Hg-contaminated areas.

• Applied Biological Chemistry
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• v.18 no.4
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• pp.194-202
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• 1975

This study was conducted to study the properties of the water-soluble natural chelating agents from garbage compost and activated sewage sludge responsible for Fe chelation, which is closely associated with the effectiveness in correcting iron chlorosis in plant. The water-soluble fraction of these materials was fractionated by menas of Sephadex gel filtration and the fractions of Fe chehates were traced by radioactive $^{59}Fe$. The fractions were examined by ultraviolet and infrared. spectroscopy and stability constants for Fe. The water-soluble fraction from garbage compost was separated by Sephadex G-25 into approximately four fractions. Most of the added $^{59}Fe$ was associated with fraction I, which appeared at the void volume. Further fractionation by Sephadex G-50 indicated that the molecular weight of water-soluble chelating agents is in the approximate range of 5000 to 10,000. The water-soluble fraction from activated sewage sludge gave six fractions by Sephadex G-25. Most of the added $^{59}Fe$ was found in the fraction I,II, and III, The molecular weights of most chelating agents associated with $^{59}Fe$ appeared to be less than 5,000 and those of fraction I that appeared at the void volume was in the range of 5,000 to 1,000. Discrepancy between radio activity count and UV absorption indicated the heterogeneity of the fractions obtained by Sephadex gel filtration. Ultraviolet absorption spectra of all fractions separated by Sephadex G-25 and containing chelating agents showed no differences. Fraction IV and V of sewage extract showed absorption maxima and shifting similar to nucleic acid components suggesting the presence of decomposition products of nucleic acid. Similarity fraction VI contained phenolic type amino acid groups. Fraction I of compost extract contained most of the added $^{59}Fe$ and showed weak but extra definite absorption in the 1230, and $1270cm^{-1}$ region, suggesting that extra oxygen groups in polyphenolic structure were probably involved in Fe chelation. In sewage extract, fraction I,II, and III in which most of the $^{59}Fe$ was found, showed strong definite polypeptide absorption in the region of $1540cm^{-1}$ due to NH deformation and C-N stretching of amide groups in the peptidebond. These extra functional groups in fraction I, II, and III appeared to be associated with Fe chelation. The other fractions, not associated with $^{59}Fe$, still have carboxyl and hydroxyl groups, suggesting that these functional groups in these water extracts may not independently form the Fe chelates. Precipitation of ferric hydroxide precluded measuring the stability constants for Fe-chelates. However, the formation constants for Zn chelates as log K values for compost extract and sewage extract at pH 4.0 from which the strength of chelation with Fe could be presumed, were 8.23, and 9.75, respectively, indicating strong complexation with metals. The chelating capacity of compost extract containing 6.5 g organic matter per liter was 0.82 mM, and that of sewage extract containing 5.3 g per liter was 0. 64 mM.

• Analytical Science and Technology
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• v.6 no.5
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• pp.489-499
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• 1993

Some sorption behaviors of U(VI) ion on Arsenazo I-XAD-2 chelating resin were investigated. This chelating resin was synthesized by the diazonium coupling of Amberlite XAD-2 resin with Arsenzo I chelating reagent and characterized by elementary analysis method and IR spectrometry. The optimum conditions for the sorption of U(VI) ion were examined with respect to pH, U(VI) ion concentration and shaking time. Total sorption capacity of this chelating resin on U(VI) ion was 0.39mmol U(VI)/g resin in the pH range of 4.0~4.5. This chelating resin was showed increased sorption capacity on the increased pH value. It was confirmed that sorption mechanism of U(VI) ion on the Arsenazo I-XAD-2 chelating resin was competition reacting between U(VI) ion and $H^+$ ion. Breakthrough volume and overall capacity of U(VI) ion measured by column were was 600 ml and 0.38 mmol U(VI)/g resin, respectively. The desorption of U(VI) ion was showed recovery of 90~96% using 3M $HNO_3$ and 3M $Na_2CO_3$ as a desorption solution. The separation and concentration of U(VI) ion from natural water and sea water was performed successfully by Arsenazo I-XAD-2 chelating resin.

• Analytical Science and Technology
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• v.6 no.1
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• pp.107-119
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• 1993

The purpose of this study is to investigated the elution behavior of platinoid metal acetylacetonates, which is the key to elucidate their retention mechanism and optimize their RPLC separation conditions. The retention data of four platinoid metal acetylacetonates have been measured on four different columns in methanol-water and acetonitrile-water systems. The retention of uncharged platinoid metal acetylacetonates is interpreted by solvophobic effect. The retention of platinoid metal acetylacetonates is also greatly influenced by the geometric structure of the complexes. The square planar chelates, $Pd(acac)_2$, $Pt(acac)_2$, are retained longer than the octahedral chelates, $Rh(acac)_3$, $Ir(acac)_3$. It is likely due to that square planar chelates show greater interaction with nonpolar stationary phase than octahedral chelates. The results of van't Hoff plots have shown that platinoid metal acetylacetonates is operated on the same retention mechanism in the temperature range of $25{\sim}45^{\circ}C$. The study of the retention mechanism by the enthalpy-entropy compensation phenomenon has indicated that the retention mechanism of octahedral chelates and square planar chelates do not vary with the composition change of methanol-water mobile phase, respectively. In acetonitrile-water mobile phase, however, the retention mechanism is observed to be more complicated. Optimum condition for the separation of four platinoid metal acetylacetonates is found to be 40% methanol, polymeric C18 column, and $45^{\circ}C$.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.19 no.1
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• pp.20-30
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• 1993

Liquid Chromatographic behavior of Pd(II) in Isonitosoethylacetoacetate imine IEAA-NR: R=H, CH3, C2H5, n-C3H7, n-C4H9, C6H5-CH2) Chelates were investigated by reversed phase high performance 1iquid chromatography on Micropak MCH-5 Column using Methanol /water as mobile phase. The optimum condition for the separation of Pd-Isonitrosoethylacetoacetate imine chelates were examined with respect to the flow rate, mobile phase strength. It was found that Pd(IEAA-NR)2 chelates were eluted in an acceptable range of the capacity factor value (0 $\leq$ log k' $\leq$ 1), The dependence of the logarithm of capacity factor(k') on the volume fraction of water in mixture with in the binary mobile phase was examined. Also, the dependence of k'on the liquid-liquid extraction distribution constant in methanol-water / n-alkane extraction system was on system was invert tigated for Pd(IEAA-NR)2. Both kinds of dependence are linear, which suggests that the retention of the electroneutral metal chelates be largely due to the solvophobic effect.

• KOREAN POULTRY JOURNAL
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• v.24 no.4 s.270
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• pp.72-74
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• 1992

• 월간낙농육우
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• v.22 no.11 s.247
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• pp.186-190
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• 2002

• KOREAN POULTRY JOURNAL
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• v.39 no.12 s.458
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• pp.130-133
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• 2007