• 대한화학회지
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• 제10권1호
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• pp.4-10
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• 1966

A new method of cobalt determination has been developed by employing ethylenediamine tetrabutyl acetate(EDTA-butyl ester) synthesized from EDTA and Butyl alcohol. The synthesized EDTA ester dissolved in butyl alcohol extracts various metal ions from aqueous solutions. Cobaltous ion extracted into organic phase containing EDTA ester to form Co (II)-EDTA butyl ester complex is back extracted into alkaline aqueous phase forming a stable pink colored complex of Co (III). The optimum condition for spectrophotometric determination of cobalt via the new complex has been established. The absorption peak occurs at 540$m{\mu}$ and Beer's law was obeyed over the concentration range of 0∼50 ${\mu}g/ml$ of cobalt.

• 분석과학
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• 제24권3호
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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.

• 한국환경보건학회지
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• 제26권4호
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• pp.110-114
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• 2000

Determination of mercury(II) using Nafion-EDTA-modified glassy carbon electrodes is proposed. it is based on the chemical reactivity of an immobilized modifier, Nafion-EDTA. Differential pulse voltammetry is employed, and the oxidation of complexes, at +0.43V vs. Ag/AgCl, is observed. For a 5-min preconcentration period, a linear calibration curve is obtained for mercury(II) concentrations ranging from 1.0$\times$ 10$^{-8}$ to 1.0$\times$10$^{-6}$ M. Further, when an approximate amount of copper(II) is added to the test solution, We demonstrate that at a preconcentration time of 5 min the Nafion-EDTA-modified glassy carbon electrode has a dynamic range of 2 orders of magnitude(from 10$^{-10}$ to 10$^{-8}$ M) and the detection limit is as low as 0.5$\times$ 10$^{-10}$ M(0.01 ppb). This method is applied to the determination of mercury(II) in sea water(4.0$\times$10$^{-10}$ M, 0.08ppb). The result agrees satisfactorily with the value(below 0.1 ppb) measured by using ICP/MS.

• 대한화학회지
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• 제13권4호
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• pp.313-316
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• 1969

모나자이트 중의 납함량을 신속하고 간편하게 결정하는 방법을 기술하였다. 즉 모나자이트 시료를 황산에 녹여 200ml가 되겠끔 희석하였다. 스트론튬으로 납을 정량적으로 분리한 후 3N 수산화나트륨에 녹였다. 여분의 Zn-EDTA를 가한 다음 남은 아연 이온을 0.01M EDTA표준용액으로 적정하였으며 이때 가리움제 (masking agent)러서 시안화칼륨 및 아세틸 아세톤을 가하였고 pH 5에서 자이렌을 오렌지(Xylenol orange)를 지시약으로 사용하였다.

• 한국환경보건학회지
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• 제28권5호
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• pp.53-58
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• 2002

A method for the determination of lead(II) ion using a nafion-EDTA(ethylene diamine tetraacetic acid)-glycerol modified glassy carbon electrode was proposed. Lead(II) ion is accumulated at the electrode by complexation and electrostatic attraction with nafion-EDTA-glycerol and detected at -0.560$\pm$0.015V (vs. Ag/AgCl) by differential pulse voltammetry. For the determination of lead(II) ion, a standard calibration curve if obtained from 10$^{-9}$ M lead(II) ion to 10$^{-7}$ M, and the detection limit(3s) is as low as 5.0$\times$10$^{-10}$ M.

• Environmental Analysis Health and Toxicology
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• 제15권3호
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• pp.99-106
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• 2000

Ethylenediaminetetraacetic acid (EDTA) and nitrilotriacetic acid (NTA) are various applied as chelating agents for metal ions, then they are widely used in many industrial processes and domestic products. A method is described for the determination of EDTA and NTA in water samples by GC/MS . The reaction temperature, reaction time and pH for esterification of EDTA and NTA were investigated using 10% sulfuric acid-methanol, ethanol and propanol. Optimum conditions were obtained by the esterification in 80$\^{C}$ for 1hr with ethanol. Method detection limits of ethylated EDTA and NTA in the 200 ml of water samples were 0.05 ng/ml, respectively, EDTA and NTA could be determined in the range of 0.05∼23.6 and 0.05∼7.0 ng/ml in treated water, and in the range of 0.06∼25.0 and 0.05∼6.40 ng/ml in raw water respectively. Risk assessments with EDTA and NTA exposure by drinking water ingestion were carried out. Based on the results of analysis, chronic daily intakes of EDTA and NTA would be less than the value of acceptable daily intake or tolerable daily intake.

• 대한화학회지
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• 제5권1호
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• pp.76-79
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• 1961

The nickel has been separated and precipitated with dimethylglyoxime in the usual manner and dissolved the precipitates with hydrochloric acid. To the nickel solution, 0.2g of Murexide as an indicator and 5 ml of 20 percent tri-ethanol amine solution were added and titrated with a standard solution of EDTA. At the end point the color changes from yellow to deep purple. In this paper, the purpose is that conditions for titration and for separation from the interfering substances were investigated and a suitable procedure was found and applied on the determination of nickel in Korean nickel ores.

• 대한화학회지
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• 제6권1호
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• pp.61-63
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• 1962

The polarographic behaviors of Tl(I) was investigated in EDTA and NTA as supporting electrolytes for determination of Tl(I). A base solution containing 0.005 % gelatine, 0.1 M EDTA, and 0.05 M NTA was used. The halfwave potential of Tl(I) determined is -0.495 V v.s. S.C.E. in 0.1 M EDTA at pH 4.1 and -0.520V v.s. S.C.E. in 0.05 M NTA at pH 6.3. In this paper, the effects of gelatine concentration and pH values was investigated. The half-wave potentials of common elements was determined and compared with the half-wave potential of Tl(I).

• 대한화학회지
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• 제6권1호
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• pp.10-13
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• 1962

Polarograph에 依한 分析方法을 利用하여 Ilmentite 鑛石에서 Titanium을 定量함에 있어서 鑛石을 酸처리하여 그 溶液을 器機에 提供함으로써 長時間 所要되는 在來의 分析方法을 避하여 迅速定量을 試圖하였다. 먼저 各種의 支待電解質에 對하여 檢詩하였으며 그 電解質에 對한 Titanium波의 定量感度와 共存하는 여러 Ion이 Titanium 波에 미치는 영향에 對하여 살폈다. 本實驗에서의 支待電解質로서는 근래에 Chelatometry$^{1)}$에서 많이 쓰이는 EDTA(Disodium etylenediamine tetraacetate)를 擇하였다. 支待電解質로서의 EDTA의 기초액 組成은 0,2M EDTA(pH=6)가 最適임을 알았다. 本支待電解質에서 Titanium의 Polarograph波가 大端히 良好하고 pH 6.3에서 $E_{1/2}$=-0.61V v.s. S.C.E.이면 또한 이 境遇에 濃度의 따라 波高가 比例하여 定量分析의 可能性을 보여 주었다.

• 한국산업보건학회지
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• 제4권2호
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• pp.189-197
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• 1994

Analytic methods for Cr(VI) level in industrial hygienic field were suggested by the National Institute for Occupational Safety and Health(NIOSH method 7600, 7604). There were growing needs for measurement of Cr(III) and Cr(VI) levels simultaneously. Two analytical methods were suggested to determine Cr(III) and Cr(VI) levels simultaneously. The one is method by using reversed phase high peformance liquid chromatography(HPLC) and the other is by using ion exchange HPLC. The purpose of this work was to evaluate the usefulness of these two analytic methods. For the difference of ionic charges of Cr(III)-ethylendiamine tetraacetic acid(EDTA) chelate and $CrO_4{^-2}$, we could detect them simultaneously by ion exchange HPLC. Also, we attempted to determine the levels of Cr(III) and Cr(VI) chelated with sodium diethyldithiocarbamate(NaDDTC) by using reversed phase HPLC. The confirmation of Cr(III) and Cr(VI) were checked by fraction collector and nameless atomic absorption spectrometer. The optimal conditions for the formation of Cr(III)-EDTA chelate were two hours incubation period with pH 5. Cr(III)-EDTA and Cr(VI) in EDTA solution were successfully separated by anion exchange column using $Na_2CO_3/NaOH$ mixture as mobile phase. Peaks of Cr(III)-EDTA and Cr(VI) in EDTA were identified at 5 minutes and 7 minutes of retention time respectively by the ion exchange HPLC. The formation of Cr(III)-NaDDTC and Cr(VI)-NaDDTC chelates were twelve hours incubation period. Cr(III)-NaDDTC and Cr(VI)-NaDDTC chelates were separated by reversed phase column using methanol and water mixture as mobile phase. Peaks of Cr(VI)NaDDTC and Cr(III)-NaDDTC chelates were identified at 13 minutes and 26 minutes of retention time respectively by the reversed phase HPLC. Due to reduction of Cr(VI) to Cr(III), it seems to be not suitable for simultaneous determination of Cr(III)-NaDDTC and Cr(VI)-NaDDTC chelates by reversed phase HPLS. Simultaneos determination of Cr(III) and Cr(VI) by ion exchange HPLC was more accurate and simple method.