• 한국식품과학회지
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• 제22권4호
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• pp.461-465
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• 1990

양조간장 중의 항산화료력을 가진 물질을 분리하고 그 특성을 알기위하여 Sephadex G-10, 50, 100을 이용하여 양조간장을 겔여과하고 각 획분에 대한 항산화성과 관련된 특성을 측정하여 다음과 같은 결과를 얻었다. 양조간장을 Sephadex G-10에서 분획한 결과 갈색도가 가장 높은 멜라노이딘 획분(MF-I)에서 항산화효력이 가장 컸고, 이 부분은 질소를 함유하고 있었으며 환원력이 매우 큰 물질이었다. Sephadex G-10에서 항산화 효력이 가장 큰 MF-I을 동결 건조하여 Sephadex G-50에서 재분획 한 결과, 갈색물질은 광범위한 범위에서 분획되었고 저분자의 멜라노이딘 부분(MF-II)에서 항산화성 및 환원력이 가장 크게 나타났다. 이 MF-II 획분을 다시 Sephadex G-100에서 재분획하여 항산화효력이 비교적 크고 환원력이 매우 큰 한 획분(MF-III)을 분리하였으나 환원력을 제외한 갈색도 및 항산화력은 상대적으로 낮았다. 그리고 양조간장의 항산화성 관련 물질의 구조적 특성을 알아보기 위해 분리한 각 획분의 UV-VIS 및 IR spectra를 측정한 결과 항산화성이 큰 각 획분(MF-I, MF-II 및 MF-III)의 UV-VIS spectra는 $260{\sim}320\;nm$에서 완만한 peak를 나타내는 전형적인 멜라노이딘의 특성을 나타내었다. 그리고 IR spectra의 경우 특징적인 OH기 및 amine기 구조를 지니고 있었고 이들이 항산화성을 갖는 기능기로 추정되었다.

• Bulletin of the Korean Chemical Society
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• 제35권11호
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• pp.3275-3279
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• 2014

A mass balance method for purity assessment of thermolabile organic reference materials was established by combining several techniques, including liquid chromatography with UV/VIS detector (LC-UV), Karl-Fischer (K-F) Coulometry, and thermal gravimetric analysis (TGA). This method was applied to three fluoroquinolones like enrofloxacin, norfloxacin and ciprofloxacin. LC-UV was used to analyze structurally related organic impurities based on UV/VIS absorbance spectra obtained in combination with LC separation. For all three organic reference materials, the UV/VIS spectra of the separated impurities were similar to that of the major component of the corresponding materials. This indicates that the impurities are structurally related to the respective reference material sharing common chromophores. Impurities could be quantified by comparing their absorbances at the wavelength of maximum absorbance (${\lambda}_{max}$). The water contents of the reference materials were measured by K-F Coulometry by an oven-drying method. The total inorganic impurities contents were assayed from ash residues in TGA analysis with using air as a reagent gas. The final purities estimated from results of those analytical techniques were assigned as ($99.91{\pm}0.06$), ($97.09{\pm}0.17$) and ($91.85{\pm}0.17$)% (kg/kg) for enrofloxacin, norfloxacin and ciprofloxacin, respectively. The assigned final purities would be applied to the reference materials which will be used as calibrators for the certification of those compounds in matrix CRMs as starting points for the traceability of their certified values to SI units.

• 약학회지
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• 제53권5호
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• pp.235-240
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• 2009

The interaction of cadmium (II) ion with quercetin was investigated in aqueous solution at different pH. The quercetin/cadmium stochiometries for cadmium (II) binding have been determined by UV-vis spectrophotometric method. The complexation of Cd(II) ion with 54.72 ${\mu}M$ quercetin (A=1.00793) was formed in 0.2 M $NH_3-0.2$ M $NH_4Cl$ (pH 8.0) buffer solution. 1:1 Cd(II)-complex had a maximum absorbance and showed the bathochromic shift of the long-wavelength band of the UV-vis spectra in the alkaline pH when interacted with quercetin in buffer solution. These results suggest that Cd(II)-quercetin complex has the optimal condition of chelation in basic buffer solution.

• 약학회지
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• 제53권6호
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• pp.342-350
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• 2009

The interaction of cadmium (II) ion with quercetin and (+)-catechin was investigated in aqueous solution at various pH. The flavonoid/cadmium stochiometries for cadmium (II) binding to quercetin and (+)-catechin have been determined by UV-vis spectroscopy. 1 : 1 Cd (II)-Flavonoid complex had a maximum absorbance and showed the bathochromic shift of the long-wavelength band of the UV-vis spectra in the alkaline pH, that occurs upon complexation, due to a ligandto-metal charge transfer. These results suggest that Cd (II)-flavonoid complex has the optimal condition of chelation in 0.2 M $NH_3$ - 0.2 M $NH_4Cl$ (pH 8.0) solution.

• 한국결정성장학회지
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• 제31권2호
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• pp.69-72
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• 2021

The reaction of ammonium ferric sulfate with sodium borohydride in laponite sol yields nanoiron colloidal solution. This solution in air forms transparent yellow brown solution. The resulting solution reacts with bidentate chelating ligands. The reaction products are characterized by UV-Vis absorption spectroscopy and X-ray diffraction. All compounds show metal to ligand charge transfer band in the region of 400~650 nm in UV-Vis absorption spectra. This indicates the formation of iron-ligand complex by air oxidation of nanoiron. Also, XRD patterns exhibit that the iron-ligand complex is intercalated in the interlayer of laponite.

• 한국세라믹학회지
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• 제52권2호
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• pp.165-170
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• 2015

We employed the high-pressure high temperature (HPHT) process to enhance the colors of natural sapphires to obtain a vivid blue. First, we analyze the content of the coloring agent $Fe_2O_3$ using the wavelength dispersive X-ray fluorescence (WD-XRF) method. The HPHT procedure operates under 1 GPa at various temperatures of 1700, 1750, and $1800^{\circ}C$ for 5 minutes using a cubic press. We determine the color changes using the optical microscopic images, UV-VIS near-infrared (NIR) spectra, micro-Raman spectra, and Fourier transform-infrared (FT-IR) spectra for all sapphire samples before and after the treatment. The optical microscopic results indicate that the HPHT process can enhance the sapphire color to a vivid blue at temperatures above $1750^{\circ}C$. The UV-VIS-NIR spectra identify the color changes explicitly and quantitatively through providing the Lab color scales and color differences. Both results demonstrate that the colors of natural sapphires can be enhanced to a vivid blue using the HPHT process above $1750^{\circ}C$ under 1 GPa for 5 minutes.

• Bulletin of the Korean Chemical Society
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• 제31권5호
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• pp.1204-1208
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• 2010

Anion recognition via hydrogen-bonding interactions could be monitored with changes in UV-vis absorption spectra and in some cases easily monitored with naked eye. Urea receptors 1 and 2 connected with both an azo group and a nitrophenyl group as a signaling group for color change proved to be an efficient naked eye receptor for the fluoride ion. The anion recognition phenomena of the receptors 1 and 2 via hydrogen-bonding interactions were investigated through UV-vis absorption and $^1H$ NMR spectra.

• 한국염색가공학회지
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• 제5권2호
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• pp.91-98
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• 1993

The silk fabrics were treated with color solution extracted from leaf of Camellia. The depression effect of destruction and yellowing of silk treated with color solution, shift of UV-VIS spectra of color solution, color difference of silk fabrics by dyeing with acid dyes and drycleaning fastness of silk treated with color solution were studied. UV-VIS spectra appeared to hypsochromic shift by irradiation. The decrease of tensile strength and the elongation of the silk treated with color solution showed depressed but those of untreated silk increased by irradiation. The yellowness index of silk treated with color solution showed a little change by irradiation. The color difference after dyeing with several acid dyes on treated and untreated silk showed not remarkable changes. Dsrycleaning fastness of silk treated by color solution was excellent.

• Bulletin of the Korean Chemical Society
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• 제35권11호
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• pp.3313-3318
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• 2014

The reaction mechanism of Lead ions catalyzing complexation reactions between TIPP and metal ions was investigated by researching the kinetics of the formation of metalloporphyrins by UV/Vis-spectra, and verified by exploring the formation of metalloporphyrins catalyzed by acetic acid. Kinetics studies suggested that the fluctuations of reaction rate indicated the formation of metalloporphyrin was step-wise, including the pre-equilibrium step (the coordination of the pyrrolenine nitrogens to $Mn^+$) and the rate-controlling step (the deprotonation of the pyrrole proton). In the pre-equalization step, a sitting-atop (SAT) structure formed first with the complexation between larger radius of $Pb^{2+}$ and TIPP, changed the activation, then $Pb^{2+}$ left with the smaller radius of metal ions attacking from the back of the porphyrin ring center. In the rate-controlling step, two pyrrole protons dissociated to restore a stable structure. This was verified by adding acetic acid at different reaction times.

• Bulletin of the Korean Chemical Society
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• 제34권1호
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• pp.231-236
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• 2013

Some cytotoxicity studies for the interpretation of the interaction between nanoparticles and cells are non-mechanistic and time-consuming. Therefore, non-biological screening methods, which are faster and simpler than in-vivo and in-vitro methods, are required as alternatives to current cytotoxicity tests. Here, we proposed a simple screening method for the analysis of the interaction between several AgNPs (bare-, citrate-, and polyvinylpyrrolidone-coating) and dye-containing vesicles acting as a biomimetic cell-membrane. The interaction between AgNPs and vesicles could be evaluated readily by UV-vis spectra. Absorbance deviation in UV-vis spectra revealed a large attraction between neighboring particles and vesicles. This was confirmed by (Derjagin, Landau, Verwey, and Overbeek) theory and DMF (dark-field microscopy) analysis. This proposed method might be useful for analyzing the cytotoxicity of nanoparticles with cell-membranes instead of in vitro or in vivo cytotoxicity tests.