• Journal of the Korean Chemical Society
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• v.10 no.1
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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.

• 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.

• Bulletin of the Korean Chemical Society
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• v.19 no.1
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• pp.50-56
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• 1998

A solvent sublation was studied for the determination of trace Cd, Co, Cu and Ni in water samples. Ammonium pyrrolidine dithiocarbamate (APDC) was used as a complexing agent. Experimental conditions such as pH of solution, amounts of APDC, the type and amount of surfactant, the type of solvent, etc. were optimized for the effective sublation of analytes. After metal-PDC complexes were formed in sample solutions of pH 2.5, the precipitate-type complexes were floated in a flotation cell with an aid of sodium lauryl sulfate as a surfactant and by bubbling with nitrogen gas. The precipitates were dissolved and separated into the surface layer of methyl iso-butyl ketone (MIBK). The analytes preconcentrated were determined by a graphite furnace atomic absorption spectrophotometry (GF-AAS). Extractability of each element was 88% for Cd(Ⅱ), 86% for Co(Ⅱ), 95% for Cu(Ⅱ) and 76% for Ni(Ⅱ), respectively. And this procedure was applied to the analysis of real samples. From the recoveries of more than 92%, it was concluded that this method could be simple and applicable for the determination of trace elements in various water samples of a large volume.

• YAKHAK HOEJI
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• v.5 no.1
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• pp.24-26
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• 1960

Micro-determination of Lead by Dithizone Method was studied as follows: 1) Max. absorption wave length of Dithizone-pb complex in CC $l_{4}$ soln. is 510m.mu., 2) at the range of 5.gamma.-120.gamma. pb content, Bourguer-Beer's law hold good, 3) co-existence of F $e^{++}$ Z $n^{++}$, and C $u^{++}$ interfere.rfere.

• Journal of Environmental Health Sciences
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• v.24 no.3
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• pp.1-5
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• 1998

A spectrophotometric method was developed for the acidic solution stripped after an extraction of 0.5 to 2.5 ppm of Lead(II) from 50 mL of $Na_2S_2O_3$ solution into chloroform as the ion-pairs formed between their thiosulfate complexes and alkylamine, Aliquat336. Pb(II) in the stripped solution forms an complex with DDTC in pH 7.3 buffer solution, and was developed in yellow by copper replacement. The ydlow-colored solution have the maximum absorbance at 435 nm in the measurement of absorbance by UV-Visible spectrophotometer. The interference ions such as Fe(III), Hg (II), Al(III), Co, Cu, Ni, Zn, Ca, Sn, have great effects on the extraction, but they were overcomed by the usage of adequate masking agents before an extraction. At last, a good result was obtained in applying this method to synthetic water.

• Bulletin of the Korean Chemical Society
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• v.32 no.2
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• pp.444-450
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• 2011

A novel method that utilizes poly(5-methyl-2-thiozyl methacrylamide-co-2-acrylamido-2-methyl-1-propanesulfonic acid-co-divinylbenzene) [MTMAAm/AMPS/DVB] as a solid-phase extractant was developed for simultaneous preconcentration of trace Cd(II), Co(II), Cr(III), Cu(II), Fe(III), Mn(II), Ni(II), Pb(II), and Zn(II) prior to the measurement by flame atomic absorpiton spectrometry (FAAS). Experimental conditions for effective adsorption of the metal ions were optimized using column procedures. The optimum pH value for the simultaneously separation of the metal ions on the new adsorbent was 2.5. Effects of concentration and volume of elution solution, sample flow rate, sample volume and interfering ions on the recovery of the analytes were investigated. A high preconcentration factor, 100, and low relative standard deviation values, $\leq$1.5% (n = 10), were obtained. The detection limits (${\mu}gL^{-1}$) based on the 3s criterion were 0.18 for Cd(II), 0.11 for Co(II), 0.07 for Cr(III), 0.12 for Cu(II), 0.18 for Fe(III), 0.67 for Mn(II), 0.13 for Ni(II), 0.06 for Pb(II), and 0.09 for Zn(II). The validation of the procedure was performed by the analysis of two certified reference materials. The presented method was applied to the determination of the analytes in various environmental samples with satisfactory results.

• Analytical Science and Technology
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• v.8 no.3
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• pp.285-292
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• 1995

Uranium has variable oxidation states(${UO_2}^{+2}$, $UO^{+2}$, $U^{+4}$, $U^{+3}$) and 1-(2-Pyridylazo)-2-naphthol forms a very stable chelate with Uranium(${UO_2}^{+2}$). The determination method of Uranium(${UO_2}^{+2}$) in 0.1M Borate buffer(pH 7.10) has been investigated by adsorptive stripping voltammetry. The optimum conditions were PAN concentration of $5{\times}10^{-7}M$, accumulation potential of 0.00V(vs. Ag/AgCl) and accumulation time of 120sec. The calibration curve was linear over the range of $5{\sim}60{\mu}g/L$ and the various metal ions did not interfere with the determination Uranium(${UO_2}^{+2}$) except Cu(II) and Co(II).

• Membrane and Water Treatment
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• v.9 no.5
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• pp.363-371
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• 2018

In this work, it was investigated the usability of artificial bee colony (ABC) and genetic algorithm (GA) in modeling adsorption of Co(II) onto drinking water treatment sludge (DWTS). DWTS, obtained as inevitable byproduct at the end of drinking water treatment stages, was used as an adsorbent without any physical or chemical pre-treatment in the adsorption experiments. Firstly, DWTS was characterized employing various analytical procedures such as elemental, FT-IR, SEM-EDS, XRD, XRF and TGA/DTA analysis. Then, adsorption experiments were carried out in a batch system and DWTS's Co(II) removal potential was modelled via ABC and GA methods considering the effects of certain experimental parameters (initial pH, contact time, initial Co(II) concentration, DWTS dosage) called as the input parameters. The accuracy of ABC and GA method was determined and these methods were applied to four different functions: quadratic, exponential, linear and power. Some statistical indices (sum square error, root mean square error, mean absolute error, average relative error, and determination coefficient) were used to evaluate the performance of these models. The ABC and GA method with quadratic forms obtained better prediction. As a result, it was shown ABC and GA can be used optimization of the regression function coefficients in modeling adsorption experiments.

• Bulletin of the Korean Chemical Society
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• v.27 no.9
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• pp.1293-1296
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• 2006

In this study, a solid phase extraction method has been developed for the preconcentration and separation of the elements Cr(III), Fe(III), Co(II) and Pb(II) at trace levels by using a column packed with Amberlite XAD-1180 resin loaded with 4-(2-pyridylazo)-resorcinol (PAR) reagent. After preconcentrating, the metals retained on the column were eluted with 20 mL of 3 mol/L $HNO_3$ and then determined by flame atomic absorption spectrometry (FAAS). The factors affecting the recovery of the elements, such as pH, type and concentration of eluent, volume of sample and elution solution, and matrix components, were also ascertained. The recoveries of Cr(III), Fe(III), Co(II) and Pb(II) were found to be $99\;{\pm}\;4,\;97\;{\pm}\;3,\;95\;{\pm}\;3$ and $98\;{\pm}\;4$%, respectively, under the optimum conditions at 95% confidence level and the relative standard deviations found by analyzing of nine replicates were $\leq4.4$%. The preconcentration factors for Cr(III), Fe(III), Co(II) and Pb(II) were found as 75, 125, 50 and 75 respectively. The detection limits (DL, 3s/b) were 3.0 $\mu g/L$ for Cr(III), 1.25 $\mu g/L$ for Fe(III), 3.3 $\mu g/L$ for Co(II), and 7.2 $\mu g/L$ for Pb(II). The recoveries achieved by adding of metals at known concentrations to samples and the analysis results of Buffalo river sediment (RM 8704) show that the described method has a good accuracy. The proposed method was applied to tap water, stream water, salt and street dust samples.

• Bulletin of the Korean Chemical Society
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• v.25 no.7
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• pp.1019-1024
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• 2004

The present paper is focused on simultaneous sorption concentration of gold (III) and silver (I) from thiocyanate solutions using high-selective anion exchanger AN-25 and subsequent separation of these ions at various concentrations of thiocarbamide (eluent). As a result, silver (I) ions are completely eluted from AN-25 and gold (III) ions remain in the resin phase and can be determined directly in the solid phase by diffuse reflection spectroscopy. It is proposed to use the sorption-spectroscopic method for Au(III) determination in aqueous solutions. The calibration curve is linear in the concentration range of 1-19 mg/L (sample volume is 10.0 mL) and the detection limit is 0.05 ${\mu}g/mL$. The presence of Cu(II), Co(II), Fe(II) do not hinder this determination. Au(III) was determined in industrial solutions.