• Journal of the Korean Chemical Society
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• v.43 no.4
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• pp.423-429
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• 1999

A spectrofluorimetric method for the determination of Fe(III) in aqueous solution with 4,5-dihydroxy-1,3-benzenedisulfonic acid(Tiron) as a fluorimetric reporter was developed. Tiron, which is very soluble in water,is a good fluorimetric reagent. However, when Tiron was complexed with Fe(III), the fluorescent intensity was decreased proportionally with the concentration of Fe(III) by a quenching effect. The excitation and fluorescene wavelength of Tiron showing the quenching effect by Fe(III) at pH 4.5 were 312 nm and 341 nm, respectively. The highest sensitivities were shown at Tiron concentration of $1.0{\times}10^{-2}M$. To enhance the quenching effect, the Fe(III)-Tiron complex solution was heated to 80$^{\circ}C$ for 90 minutes. As for Fe(III), the most interfering ion was Cu(II). The interference effects could be mostly eliminated by pH adjustment or by adding EDTA. The concentration ranges showing the linear response to Fe(III) was from $5.0{\times}10^{-7}M\;to\;6.0{\times}10^{-5}M$ With this proposed method, the detection limits of Fe(III) was $2.8{\times}10^{-6}M$. Recovery of Fe(lII) in a synthetic sample was almost quantitative. Based on experimental results, it is proposed that the above technique can be applied to the practical determination of Fe(III).

• Bulletin of the Korean Chemical Society
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• v.32 no.9
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• pp.3400-3404
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• 2011

A new rhodamine B-coumarin conjugate (1) capable of recognizing both $Cu^{2+}$ and $Fe^{3+}$ using two different detection modes have been designed and synthesized. The metal ion induced optical changes of 1 were investigated in $CH_3CN-H_2O$ (1:1, v/v, HEPES 50 mM, pH = 7.0) solution. Sensor 1 exhibits selective colorimetric recognition of $Cu^{2+}$ and fluorescent recognition of $Fe^{3+}$ with UV-vis and fluorescence spectroscopy, respectively. Moreover, both of the $Cu^{2+}$ and $Fe^{3+}$ recognition processes are observed to be barely interfered by other coexisting metal ions.

• Carbon letters
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• v.24
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• pp.103-110
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• 2017

Carbon-based magnetic nanostructures in several instances have resulted in improved physicochemical and catalytic properties when compared to multi-wall carbon nanotubes (MWCNTs) and magnetic nanoparticles. In this study, magnetic MWCNTs with a structure of $Ni_xZn_xFe_2O_4/MWCNT$ as peroxidase mimics were fabricated by the one-pot hydrothermal method. The structure, composition and morphology of the nanocomposites were characterized with X-ray diffraction (XRD), Fourier transform infrared spectroscopy and transmission electron microscopy. The magnetic properties were investigated with a vibrating sample magnetometer. The peroxidase-like catalytic activity of the nanocomposites was investigated by colorimetric and electrochemical tests with 3,3',5,5'-tetramethylbenzidine (TMB) and $H_2O_2$ as the substrates. The results show that the synthesis of the nanocomposites was successfully performed. XRD analysis confirmed the crystalline structures of the $Ni_xZn_xFe_2O_4/MWCNT$ nanohybrids and MWCNTs. The main peaks of the $Ni_xZn_xFe_2O_4/MWCNT$s crystals were presented. The $Ni_{0.25}Zn_{0.25}Fe_2O_4/MWCNT$ and $Ni_{0.5}Zn_{0.5}Fe_2O_4/MWCNT$ nanocatalysts showed nearly similar physicochemical properties, but the $Ni_{0.5}Zn_{0.5}Fe_2O_4/MWCNT$ nanocatalyst was more appropriate than the $Ni_{0.25}Zn_{0.25}Fe_2O_4/MWCNT$ nanocatalyst in terms of the magnetic properties and catalytic activity. The optimum peroxidase-like activity of the nanocatalysts was obtained at pH 3.0. The $Ni_{0.5}Zn_{0.5}Fe_2O_4/MWCNT$ nanocatalyst exhibited a good peroxidase-like activity. These magnetic nanocatalysts can be suitable candidates for future enzyme-based applications such as the detection of glucose and $H_2O_2$.

• 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.

• Bulletin of the Korean Chemical Society
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• v.31 no.7
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• pp.1976-1980
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• 2010

A simple and reliable method has been developed to selectively separate and concentrate trace amounts of Fe(III) ions from water and food samples by using flame atomic absorption spectrometry. A new reagent, 5-hydroxy-4-ethyl-5,6-di-pyridin-2-yl-4,5-dihydro-2H-[1,2,4] triazine-3-thione, was synthesized and characterized by using FT-IR spectroscopy and elemental analysis. Effects of pH, concentration and volume of elution solution, sample flow rate, sample volume and interfering ions on the recovery of Fe(III) were investigated. The optimum pH was found to be 5. Eluent for quantitative elution was 10 mL of 2 M HCl. The preconcentration factor of the method, detection limit (3s/b, ${\mu}gL^{-1}$) and relative standard deviation values were found to be 25, 4.59 and 1%, respectively. In order to verify the accuracy of the method, two certified reference materials (TMDA 54.4 lake water and SRM 1568a rice flour) were analyzed. The results obtained were in good agreement with the certified values. The method was successfully applied to the determination of Fe(III) ions in water and food samples.

• Corrosion Science and Technology
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• v.17 no.2
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• pp.60-67
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• 2018

The compounds associated with corrosion, in metallic archaeological samples of carbon steel of insular origin were evaluated to establish their degree of deterioration and structural damage against air pollution. The iron phases present in samples of archaeological artifacts were detected by Raman spectroscopy and confocal Raman microcopy. These samples mainly exhibited ing mainly ${\beta}$-FeO(OH) type goethite oxyhydroxides and small amounts of akaganeite ${\alpha}$-FeO(OH) lepidocrocite ${\gamma}$-FeO(OH) due to dominant chloride in a marine environment and non-stoichiometric oxyhydroxides Fe (II + / III +) as indicators of early corrosion. Some parts showed the presence of magnetic maghemite indicating high corrosion. ${\gamma}$-FeO(OH) is a precursor of phases associated with advanced marine corrosion. By studying its decomposition by Raman spectroscopy, it was synthesized with the following sequence: ${\gamma}-FeO(OH){\rightarrow}{\alpha}-FeO(OH)+{\gamma}-FeO(OH)$, ${\rightarrow}{\gamma}-Fe_2O_3+Fe_3O_4$. Ferric compounds provided evidence for the effect of intensity of laser on them, constituting a very useful input for the characterization of oxidation of iron in this type of artifacts. Thus, destructive analysis techniques should be avoided in addition to the use of small amounts of specimen.

• Journal of the Korea institute for structural maintenance and inspection
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• v.28 no.2
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• pp.27-34
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• 2024

This study was conducted to examine the feasibility of using Fe-activated wood-derived biochar as a conductive filler for manufacturing cement-based strain sensor. To evaluate the compressive and electrical properties of cement composite with 3% Fe-activated biochar, three cubic specimens of size 50 x 50 x 50mm³ and three prismatic cement-based sensors of size 40 x 40 x 80mm³ were prepared respectively. The four-probe method of electrical resistance measurement was used for cement-based sensors. For cement-based sensors with FE-activated biochar, the conductive performance such as electrical resistance and impedance under different water content and repeated compression was investigated. Results showed that the fractional changes in the DC electrical resistivity of cement-based sensors increase with increasing time and the maximum fractional changes in the resistivity decrease with increasing the moisture contents during 900s. At moisture content of 7.5% range, the conductive performance of cement composite including 3% Fe-activated biochar as a conductive filler showed the most stable, while the strain detection ability tended to decrease somewhat as the repeated compressive stress increased between repeated compressive strain and fractional change in resistivity (FCR).

• The Bulletin of The Korean Astronomical Society
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• v.37 no.1
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• pp.74.2-74.2
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• 2012

We present [Fe II] 1.64 ${\mu}m$ imaging observations for jets and outflows from young stellar objects over the northern part (-24'${\times}$45') of the Carina Nebula, a typical evolved massive star forming region. The observations were performed with IRIS2 of Anglo-Autralian Telescope and the seeing was -1.5". Several jets and outflows features are detected at seven different regions, and one new Herbig-Haro Object is identified. The [Fe II] features have knotty and elongated shapes, and distribute around the triangular area formed by the star clusters Tr 14, Tr 15, and Tr 16, which contain many massive stars. The [Fe II] feature shows a highest detection rate (3.2 %) for the earliest stage YSOs, and the rate decreases as the stage evolves. The low detection rate (1.5 %) of [Fe II] features from the numerous YSOs seem to be related with the severe radiation environment of the Carina Nebula. The outflow rate shows reasonable relations with the physical parameters of the corresponding YSOs-derived from the SED fitting-such as the accretion luminosity, the stellar mass, the stellar age, the disk accretion rate, etc.

• Biotechnology and Bioprocess Engineering:BBE
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• v.10 no.6
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• pp.505-509
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• 2005

For the purpose of developing a direct label-free electrochemical detection system, we have systematically investigated the electrochemical signatures of each step in the preparation procedure, from a bare gold electrode to the hybridization of label-free complementary DNA, for the streptavidin-modified electrode. For the purpose of this investigation, we obtained the following pertinent data; cyclic voltammogram measurements, electrochemical impedance spectra and square wave voltammogram measurements, in $Fe(CN)_6^{3-}/Fe(CN)_6^{4-}$ solution (which was utilized as the electron transfer redox mediator). The oligonucleotide molecules on the streptavidin-modified electrodes exhibited intrinsic redox activity in the ferrocyanide-mediated electrochemical measurements. Furthermore, the investigation of electrochemical electron transfer, according to the sequence of oligonucleotide molecules, was also undertaken. This work demonstrates that direct label-free oligonucleotide electrical recognition, based on biofunctional streptavidin-modified gold electrodes, could lead to the development of a new biosensor protocol for the expansion of rapid, cost-effective detection systems.

• Journal of the Korea Computer Industry Society
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• v.3 no.7
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• pp.901-914
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• 2002

In this paper, We propose an efficient automatic caption detection and location method, caption recognition using FE-MCBP(Feature Extraction based Multichained BackPropagation) neural network for content based retrieval of video. Frames are selected at fixed time interval from video and key frames are selected by gray scale histogram method. for each key frames, segmentation is performed and caption lines are detected using line scan method. lastly each characters are separated. This research improves speed and efficiency by color segmentation using local maximum analysis method before line scanning. Caption detection is a first stage of multimedia database organization and detected captions are used as input of text recognition system. Recognized captions can be searched by content based retrieval method.