• Title/Summary/Keyword: 코발트 정량

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Direct and Derivative Spectrophotometric Determination of Cobalt (II) in Microgram Quantities with 2-Hydroxy-3-methoxy Benzaldehyde Thiosemicarbazone (2-Hydroxy-3-methoxy Benzaldehyde Thiosemicarbazone를 사용하여 마이크로 그램 코발트(II)의 직접 및 유도 분광광도법에 의한 정량)

  • Kumar, A.Praveen;Reddy, P.Raveendra;Reddy, V.Krishna
    • Journal of the Korean Chemical Society
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    • v.51 no.4
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    • pp.331-338
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    • 2007
  • A rapid, simple and sensitive spectrophotometric method was developed for the determination of cobalt(II) using 2-hydroxy-3-methoxy benzaldehyde thiosemicarbazone (HMBATSC) as a analytical reagent. The metal ion in aqueous medium forms a brown coloured complex with HMBATSC at pH 6.0. The complex has two absorption maxima at 375 nm and 390 nm. At 375 nm, the reagent shows considerable absorbance, while at 390 nm the reagent does not shows appreciable absorbance. Hence, analytical studies were carried out at 390 nm. Beer's law is obeyed in the range of 0.059-2.357 μg ml-1 of Co(II). The molar absorptivity and Sandall's sensitivity of the method are 2.74×104 l mol-1 cm-1 and 0.0024 μg cm-2 respectively. The interference of various diverse ions has been studied. The complex has 1:2 [Co(II)- HMBATSC] stoichiometry. A method for the determination of cobalt(II) by second order derivative spectrophotometry has also been proposed. The proposed methods were applied for the determination of cobalt(II) in alloy steels, vitamin B12 and in some biological samples.

Use of High Molecular Alkylamines in the Simultaneous Determination of Copper and Cobalt by Spectrophotometry (구리와 코발트의 분광광도법에 의한 정량에 있어서 고분자량 알킬아민의 이용)

  • Chon Han Kim;Chan Ho Jee;Ki Tae Sung;Chang Ung Joung
    • Journal of the Korean Chemical Society
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    • v.33 no.2
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    • pp.208-214
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    • 1989
  • A method for the simultaneous determination of copper and cobalt by spectrophotometry has been described. The procedure involves the co-extraction of Cu(Ⅱ) and Co(Ⅱ) from 0.3M HCl into methyl isobutyl ketone as the ion-pairs formed between their thiocyanate complexes and high molecular alkylamines such as Amberlite LA1, Alamine 336, and Aliquat 336. The extract shows the color development to have the maximum absorbances at two different wavelengths i.e., 480 nm for copper and 625 nm for cobalt. Since the spectra of the ion-pairs overlap each other, two simultaneous equations are used to obtain the concentrations from absorbances. Even small amount of Fe(Ⅲ) and Ni(Ⅱ) interferes with the determination of copper. The results of the analysis of samples are in good agreement with the results determined by separate methods within RSD 5.9%.

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New Analytical Method for Separation and Identification of Heavy Metals (I) (중금속의 분리 및 검출을 위한 분석화학적 연구 (제 1 보). 새로운 분리방법의 개발)

  • Kim, Youn-Doo;Bae, Jun-Heon;Shin, Young-Kook
    • Journal of the Korean Chemical Society
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    • v.31 no.3
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    • pp.231-235
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    • 1987
  • In 10M chloride (4M HCl + 6M LiCl) solution, cobalt, but not nickel, formed complex anion (${CoCl_3}^-$), and this anion was extracted by a liquid anion exchanger with Amberlite LA-2. The ion exchange capacity was 2.175meq of cobalt complex per unit ml of Amberlite LA-2. Upon eluting the resin with 0.4M nitric acid, the cobalt complex was stripped and transfered into eluate quantitatively. By using this separation method in the chloride solution dissolved with 50mg of cobalt (II) and 500mg of nikel(II), recovery of cobalt were 99.6 percent.

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Flow Injection Spectrophotometric Determination of Cobalt with 2-(5-Bromo-2-pyridylazo)-5-(N-propyl-N-sulfopropylamino)aniline (2-(5-브로모-2-피리딜아조)-5-(N-프로필-N-슬포프로필아미노)아닐린을 사용하여 흐름주입법에 의한 코발트의 분광광도법적 정량)

  • Kang, Sam Woo;Kim, In Yong;Han, Hong Seok;Lee, Seung Seok
    • Analytical Science and Technology
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    • v.6 no.1
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    • pp.57-63
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    • 1993
  • Spectrophotometric determination of cobalt by flow injection method is described. 2-(5-Bromo-2-pyridylazo)-5-(N-propyl-N-sulfopropylamino) aniline rapidly forms a water-soluble complex with cobalt in $NH_3-NH_4Cl$ buffer solution at pH 10.5. The absorption maxima of this complex is at 545 nm with molar absorptivity of $58000L\;mol^{-1}\;cm^{-1}$. The calibration curve of cobalt is linear over the range of 0.1 to 0.6ppm and the detection limit is 25ppb. The relative standard deviation is ${\pm}0.72%$ for 0.5ppm and the sampling rate is $60samples\;hr^{-1}$. The interfering effect of some cations and anions was investigated. Ni(II), Cu(II), Fe(III) and $CN^-$ interfered severely. The interfering effect of these matallic ions could be decreased by adding $1.0{\times}10^{-3}M$ EDTA solution to the carrier stream.

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Separation and Determination of Co(II) and Ni(II) Ion as their 4-(2-Pyridylazo) resorcinol Chelates by Reversed-Phase Capillary High-Performance Liquid Chromatography (역상 모세관-고성능 액체 크로마토그래피에 의한 코발트와 니켈 이온의 4-(2-피리딜아조)레조루신올 킬레이트로서의 분리 및 정량)

  • Chung, Yong-Soon;Chung, Won-Seog
    • Journal of the Korean Chemical Society
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    • v.47 no.6
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    • pp.547-552
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    • 2003
  • Separation and determinations of Co(II) and Ni(II) ions as their 4-(2-pyridylazo)resorcinol(PAR) chelates by reversed-phase capillary high-performance liquid chromatography(RP-CpHPLC) were performed. Among many capillary columns, Vydac C4 column was selected and acetonitrile solution was used as mobile phase. The effect of pH and MeCN concentration(%) on the retention factor, k and peak intensity was examined and discussed. As a results, it was found that 22.5% MeCN and pH 5.60 was adequate as mobile phase for the separation of the two metal ions and determination of Co(II) ion, but the mobile phase condition for Ni(II) ion determination was 22.5% MeCN of pH 7.20. Detection limit(D.L., S/N=3) of Co(II) and Ni(II) ions were $2.0{\times}10{-7}$ M(14.9 ppb) and $1.0{\times}10{-6}$ M(59.2 ppb), respectively.

Preparation of Cobalt-Substituted Iron Oxide Powder from Organometallic Precursors (Ⅱ) (유기금속 전구체로부터 코발트 치환 산화철 분말 제조 (Ⅱ))

  • Kim, Jeong Su;Gang, Han Cheol;Hong, Yang Gi
    • Journal of the Korean Chemical Society
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    • v.38 no.2
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    • pp.92-100
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    • 1994
  • Ultrafine cobalt-substituted iron oxide particles were prepared by the thermal decomposition and oxidation of the new organometallic precursor, $Co_xFe_{1-x}(N_2H_3COO)_2(N_2H_4)_2$ (x = 0, 0.01, 0.02, 0.03, 0.05, 0.10, 1.00). The organometallic precursors were synthesized by the reaction of Co(II) and Fe(II) ion in a mole ratio of x : 1-x with hydrazinocarboxylic acid, and characterized by quantitative analysis, elemental analysis and infrared spectroscopy. The mechanistic study on the thermal decomposition of the organometallic precursors was performed by TG-DTG and DSC. The cobalt-substituted iron oxide particles were obtained by the heat treatment of the precursors at $350^{\circ}C$ and $450^{\circ}C$ for six hours in air. The prepared iron oxide was found to have two phases such as ${\gamma}-Fe_2O_3$ and a mixture of ${\gamma}-Fe_2O_3\;and\;{\alpha}-Fe_2O_3$ at $350^{\circ}C$ and $450^{\circ}C$ respectively. The particle shape was equiaxial and the particle size was less than 0.05 ${\mu}m.$ The coercivity and squareness of the cobalt substituted iron oxide particles increased with increasing cobalt content. Both coercivity and squareness showed higher values at $450^{\circ}C.$

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Studies on X-Ray Fluorescence Analysis of Sulfide Ores by Solution Technique (II). Analysis of Iron, Copper and Cobalt (용액법을 이용한 황화광석의 X-선 형광분석에 관한 연구 (제2보). 철, 구리 및 코발트의 분석)

  • Young-Sang Kim;Kee-Chae Park
    • Journal of the Korean Chemical Society
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    • v.26 no.5
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    • pp.320-325
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    • 1982
  • Utilyzing the solution prepared for the sulfur determination, the amounts of iron, copper and cobalt in the sulfide ore were determined by X-ray fluorescence spectrometry. The samples were dissolved with the mixed solutions of ,$Br_2\;and\;HNO_3$ and a major constituent of $SiO_2$was repelled from the solution by HF treatment several times. The analytical results agreed with the data obtained by conventional methods within ${\pm}$1.5% for Fe of the range of 20 to 50%, ${\pm}$1.0% for Cu of 10 to 15%, and ${\pm}$0.4% for Co of 1 to 5%. The present method was tolerably found to be reproducible.

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Preconcentration and Determination of Trace Cobalt and Nickel by the Adsorption of Metal-PDC Complexes on the Anion-Exchange Resin Suspension (금속-PDC 착물의 음이온교환 수지 상 흡착에 의한 흔적량 코발트와 니켈의 동시 예비농축 및 정량)

  • Han, Chul-Woo;In, Gyo;Choi, Jong-Moon;Kim, Sun Tae;Kim, Young-Sang
    • Analytical Science and Technology
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    • v.13 no.5
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    • pp.608-615
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    • 2000
  • A determination method of trace nickel and cobalt in water samples was studied and developed by adsorbing their complexes on ion exchange resin suspension. The analytical ions were formed as complexes with a ligand of APDC (ammonium pyrrolidinedithiocarbamate) and adsorbed on anion exchange resin of Dowex 2-X8. After the suspension was filtered out with membrane filter, the complexes were dissolved in HCl solution by an ultrasonic vibrator for ET-AAS determination. Several conditions were optimized as followings. pH of sample solution: 5.0, amount of ligand APDC: more than 430 times in mole ratio, the type and concentration of acid: 0.1 M HCl, and vibration time: 7 minutes. The addition of palladium in the HCl solution could improve the reproducibility and sensitivity by a matrix modification in the absorbance measurement. This procedure was applied for the analysis of three kinds of real water samples. The detection limits equivalent to 3 times standard deviation of blank were Co 0.36 ng/mL and Ni 0.27 ng/mL and recoveries in spiked samples were 99-102% for cobalt and 100-105% for nickel.

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Precipitation of Cu as the sulphide from Sulphate solution containing Cu, Ni and Co (구리, 니켈, 코발트 혼합용액으로부터 침전법에 의한 구리의 분리)

  • Park Kyung-Ho;Jung Sun-Hee;Park Jin-Tae;Nam Chul-Woo;Kim Hong-In
    • Resources Recycling
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    • v.14 no.6 s.68
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    • pp.16-20
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    • 2005
  • The selective sulphide precipitation of copper from sulphate solution containing nickel and cobalt was studied with adding $Na_{2}S$ solution. Precipitation efficiency of copper increased with raising pH of solution and increasing the amount of $Na_{2}S$ added and lowing its concentration. The increase in reaction time and temperature also improved the precipitation of copper. However, attempts to selectively precipitate copper met with limited success because of co-precipitation of nickel and cobalt. With adding $20\%$ $Na_{2}S$, 3 times equivalent of Cu, at pH 1.0 of solution, $25^{\circ}C$ and 30 minutes of reaction time, precipitation efficiencies of copper, nickel and cobalt were $94.1\%$, $4.3\%$ and $4.5\%$ respectively.

Organic Precipitate Flotation of Trace Metallic Elements with Ammonium Pyrrolidinedithiocarbamate(Ⅰ). Determination of Bismuth, Cadmium, Cobalt and Lead in Water Samples by Coprecipitation-Flotation with Cu-pyrrolidinedithiocarbamate (Ammonium Pyrrolidinedithiocarbamate에 의한 극미량 금속원소의 유기침전 부선에 관한 연구(제1보) Cu-pyrrolidinedithiocarbamate 공침부선에 의한 물시료중 비스무트, 카드뮴, 코발트 및 납의 정량)

  • Jung, Yong June;Choi, Jong Moon;Choi, Hee Seon;Kim, Young Sang
    • Journal of the Korean Chemical Society
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    • v.40 no.12
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    • pp.724-732
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    • 1996
  • The organic precipitate flotation using Cu(II)-pyrrolidinedithiocarbamate complex as a coprecipitant was studied for the preconcentration and determination of trace Cd, Pb, Bi and Co in several water samples. Experimental conditions such as pH of solution, amounts of Cu(II) and ammonium pyrrolidinedithiocarbamate(APDC), stirring time, the type and amount of surfactant, etc. were optimized for the effective flotation of analytes. After 3.0 mL of 1,000 ${\mu}g/mL$ Cu(II) solution was added to 1.00 L water sample, the pH of the solution was adjusted to 2.5 with HNO3 solution. Trace amounts of analytes were coprecipitated by adding 2.0% APDC solution. And the precipitates were flotated onto the surface of solution with the aid of nitrogen gas and sodium lauryl sulfate. The floats were collected from mother liquor, and filtered through the micropore glass filter by suction. The precipitates were dissolved with 4 mL conc. HNO3, and then diluted to 25.00 mL with deionized water. The analytes were determined by graphite furnace atomic absorption spectrophotometry. This flotation technique was applied to the analysis of some water samples, and the 90 to 120% of recoveries were obtained from the spiked samples, this procedure could be concluded to be simple and applicable for the trace element analysis in various kinds of water.

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