• Bulletin of the Korean Chemical Society
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• v.29 no.1
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• pp.99-103
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• 2008

Solvent extraction using salphen as a ligand has been investigated for the selective separation and determination of trace Fe(II) and Fe(III). A salphen ligand was synthesized, and solvent extraction variables, such as solution pH, the concentration of salphen, the type of organic solvent, auxiliary agents, oxidants and the effect of interference were optimized. Salphen is stable at pH 3-4, and Fe(III)-salphen complexes can be selectively extracted into an MIBK(4-methyl-2-pentanone) phase from an aqueous solution within this pH range. For the determination of the total amount of iron in 100 mL of aqueous solution, Fe(II) ions were completely oxidized using 0.05 mL of 3.5% H2O2 without side reactions. To evaluate its applicability, the proposed method was applied to determine trace Fe(II) and Fe(III) in several kinds of water samples. Reproducible results were obtained with RSD of less than 3.0%, and the recoveries for this reliability were obtained with 91-112%.

• YAKHAK HOEJI
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• v.13 no.1
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• pp.28-32
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• 1969

For the colorimetric determination of Sulfa-drugs by means of solvent extraction, the sample solutions were added into dimethylglyoxime-Fe(II) complex solution, and extracted with pyridine-chloroform mixture (1:50) is a range of pH 7.5-8.5. The extracted solution shows stability and maximum absorption at 402m${\mu}$.

• Analytical Science and Technology
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• v.24 no.3
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• pp.231-235
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• 2011

A spectrofluorimetric method for the determination of EDTA in real samples such as mayonnaise, powder detergent and cleansing cream with tiron (4,5-dihydroxy-1,3-benzenedisulfonic acid) as a fluorimetric reporter was developed. When tiron is chelated with Cu(II), the fluorescent intensity is decreased by a quenching effect. However, when Cu(II)-tiron chelate reacts with EDTA, fluorescent intensity is increased as tiron is released. Several experimental conditions such as pH of the sample solution, the amount of Cu(II), the amount of tiron, heating temperature and heating time were optimized. Fe(III) interfered more seriously than any other ions, interference of Fe(III) could be disregarded, because Fe(III) was scarcely contained in selected real samples. The linear range of EDTA was from $8.0{\times}106{-8}\;M$ to $2.0{\times}10^{-6}\;M$. With this proposed method, the detection limit of Fe(III) was $5.2{\times}10^{-8}\;M$. Recovery yields of 92.7~99.3% were obtained. Based on experimental results, it is proposed that this technique can be applied to the practical determination of EDTA.

• YAKHAK HOEJI
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• v.16 no.4
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• pp.180-185
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• 1972

A new spectrophotometric method was established for the determination of undecylenic acid. The method is based on the solvent extraction into nitrobenzene of the ion pair formed between tris(1,10-phenanthroline)Fe(II) chelate and the anion of undecylenic acid. The maximum absorbance of the extract in the organic phase was at 518nm. A maximum extraction was obtained at pH 9-11, when excess of at least 50-fold(molar) of the phenanthroline-Fe(II) chelate to undecylenic acid was present. The color intensity of the extracted species remained constant at room temperature for the several hours after separation of the organic layer. A linear relationship was obtained over the tested range of 5-20${\gamma}$/ml of undecylenic acid. The effect of several other fungicids on this method was investigated. The method was applied to the determination of undecylenic acid in preparations and the results were in good agreement with those added amounts.

• YAKHAK HOEJI
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• v.13 no.1
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• pp.22-27
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• 1969

Nicotinamide Complex Compound was not formed in simple alkaline solution under two to one molar ratio of dimethyglyoxime and Fe (II), but it was formed with ammonia or pyridine under the same molar ratio. Based on this fact, nicotinamide solution was added into dimethyglyoxime-Fe (II) complex solution, and the chelation product was extracted with chloroform. The extraction was Completed in a range of pH 8.4-11.0. The chloroform solution shows stability and maximum absorption at 516 m${\mu}$.

• Applied Chemistry
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• v.15 no.2
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• pp.113-116
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• 2011

A sensitive and selective determination method of Fe(II) ion by luminol-H₂O₂ system using a chelating reagent has been presented. A metal ion-chelating ligand complex such as Fe(II)-diethylenetriamine pentaacetic acid (DTPA) produced higher chemiluminescence (CL) intensity as well as longer lifetime in luminol-H₂O₂ system than metal exist as free ions. Furthermore, the catalytic activity of Cu(II) and Pb (II) complexes with chelating reagents in luminol-H₂O₂ system was lost since chelating reagents act as a masking agent although free Cu(II) and Pb(II) ions have high catalytic activity. On the optimized conditions, the calibration curve of Fe(II) ion was linear over the range from 1.0×10^-7 to 2.0×10^-5 M with correlation coefficient of 0.996. The detection limit was calculated to be 4.0×10^-8 M.

• Journal of the Korean Chemical Society
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• v.47 no.2
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• pp.115-120
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• 2003

Determination of iron(II) ion with a perfluorinated sulfonated polymer(nafion)-ethylenediamine(en) modified glassy carbon electrode was studied. It was based on the chemical reactivity of an immobilized layer(nafion-en) to yield complex $[Fe(en)_3]^{+2}$. The oxidation peak potential by differential pulse voltammetry(DPV) was observed at 0.340${\pm}$0.015 V(vs. Ag/AgCl). The linear calibration curve was obtained in iron(II) ion concentration range $5{\times}10^{-6}{\sim}0.2{\times}10^{-3} M(0.28{\sim}11.17\; mg/L)$, and the detection limit(3s) was $1.89{\times}10^{-5}$M(1.056 mg/L).

• Journal of the Korean Chemical Society
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• v.46 no.6
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• pp.509-514
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• 2002

A method to determin Fe(II) and Fe(III) ion in aqueous solution by chemiluminescence method using a stopped flow system has been studied. The method is based on the increased chemiluminescence intensity with the addition of Fe(III) ion to a solution of lucigenin and hydrogen peroxide. The effects of KOH concentration, flow rate of reagents, $H_2O_2$ concentration and citric acid concentration used for the masking of Fe(II) ion on the chemilu-minescence intensity have been investigated. The calibration curve for total Fe was linear over the range from 1.0${\times}$$10^{-6}$ M to 1.0${\times}$$10^{-4}$M, coefficient of correlation was 0.996 and the detection limit was 1.0${\times}$$10^{-7}$M under the optimal exper-imental conditions of 4.0 M, 2.0 M, 3.5 mL/min for the concentration of $H_2O_2,$ KOH and flow rate of reagents, respec-tively. The calibration curve for Fe(Ⅲ) was linear over the range from 1.0${\times}$$10^{-6}$M to 1.0${\times}10^{-4}$ M, the coefficient of correlation was 0.997 and the detection limit was 5.0${\times}$$10^{-7}$M under the optimal experimental conditions.

• Journal of the Korean Chemical Society
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• v.46 no.5
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• pp.419-437
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• 2002

An analytical method for the spectrometric simultaneous determination of the individual ions in the mix-tures of $Fe^{2+}$ and $Fe^{2+}$ ions utilizing a technique of flow injection analysis has been developed. The method was based on the oxidation reaction between $Fe^{2+}$ ion and $H_2O_2$ in an acidic medium and the subsequent formation of a red Fe$(SCN)^{3-x}_x$ ion by the complexation reaction between $Fe^{2+}$ ion and $SCN^-$ ion. Unlike the conventional methods which require separate processes for the pre-treatment of the sample solution, the current method uses the same FIA system for the pre-treatment and the analysis of the sample. The detection limit for the determination of $Fe^{2+}$ ion was found to be 6.00${\times}10^{-7}$M.

• Analytical Science and Technology
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• v.12 no.6
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• pp.515-520
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• 1999

The spectrophotometric determination of Al(III) with thorin have been investigated. The optimum condition of pH, concentration of ligand and surfactant, and stability were evaluated. The thorin ligand offers selective separation of Al(III) from sample solution containing Fe(III), Ni(II), Cu(II), Pb(II) and Cu(II). Various surfactants were tested and Triton X-100 showed the best stability and the maximum absorbance in an aqueous solution of Al(III)-Thorin-Triton X-100 complex appears about 526 nm. The method was applied for the determination of Al(III) in mixed sample solution. Separation and preconcentration was performed with a short column filled with resorcinol-formaldehyde resin. Control of the pH during the column operation is essential because the adsorption capacities are very sensitive to change in pH. Their separation was carried out in 0.2 M acetic acid-sodium acetate buffer solution (pH 4.5) and 1.0 M $HNO_3$media.