• Polymer(Korea)
• /
• v.34 no.4
• /
• pp.376-380
• /
• 2010

Donor-$\pi$-acceptor (D-$\pi$-A) type chromophore-based polymers were newly synthesized. These polymers exhibited absorption peak due to intramolecular charge transfer (ICT) in a visible range as well as absorption peak due to carbonyl group in both solution and film state by measuring UV visible spectra. The addition of $Eu^{3+}$ ion into the polymers induced red-shift in absorption due to ICT and the color changes from yellow to red in the solution and film were observed by naked eyes. The contents of crosslinking agent influenced the features and solubility of the polymers. In addition, the contents of crosslinking agent and the $Eu^{3+}$ ion addition improved film-forming ability.

• Korean Journal of Food Science and Technology
• /
• v.50 no.1
• /
• pp.1-7
• /
• 2018

The MTT [3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide] assay is commonly used for analyzing the cell viability. In this study, effects of various solvents, different lights, and zinc protoporphyrin (ZnPP) on the chemical behavior of MTT formazan were investigated. The color response of MTT formazan in NaOH was highly pronounced; the absorbance of MTT formazan in 0.1 N NaOH at 550 nm was >2-fold higher than that in water, dimethyl sulfoxide (DMSO), methanol, and ethanol. MTT formazan in DMSO and NaOH (>0.1 N) was relatively stable under fluorescent and UV light at 365 nm; its rapid degradation was induced under UV light at 254 nm in all solvents. ZnPP degraded MTT formazan under light in a time- and concentration-dependent manner; MTT formazan in 0.1 N NaOH was the most sensitive to ZnPP, followed by DMSO. These results suggest that NaOH and DMSO might be suitable media for MTT formazan for monitoring photosensitizing properties.

• Korean Journal of Food Science and Technology
• /
• v.10 no.3
• /
• pp.356-360
• /
• 1978

To determine the total saponin extracted by Shibata method, of Ginseng jellies and candies, $vanillin-H_2SO_4$ coloring method, direct drying method and thinchrographic method were compared after samples were treated with methanol to remove sugars. Thinchrographic method was the more reproducible than direct drying method and $vanillin-H_2SO_4$ coloring method was interfered significantly by sugars.

• Applied Chemistry for Engineering
• /
• v.35 no.2
• /
• pp.67-78
• /
• 2024

Light absorption has potential as a signal in biochemical analyses due to its simplicity in measurement and interpretational clarity. Among substances that generate absorption signals, gold nanoparticles possess advantages such as chemical stability, biological compatibility, and unique optical properties from the localized surface plasmon resonance (LSPR) in the visible light range. They also exhibit versatility compared to other colorimetric substances effective only for specific target molecules, as they easily conjugate with various detection active substances like antibodies and aptamers. Particularly due to advantages such as low cost, ease of particle synthesis, and high environmental stability compared to enzyme-based colorimetric methods, gold nanoparticles are extensively researched as signal substances in colorimetric assays. This review summarizes various strategies utilizing gold nanoparticles as absorption signal substances, focusing on recent research. Based on the characteristics of gold nanoparticles, where the optical property is influenced by particle morphology, literature is classified and reviewed based on strategies controlling the shape of gold nanoparticles during signal generation. Through this, it is observed that gold nanoparticles, which have been used as absorption signal substances, continue to be actively researched, affirming their potential for broad and continuous improvement in the future.

• Journal of Food Hygiene and Safety
• /
• v.5 no.4
• /
• pp.237-242
• /
• 1990

This study was conducted to evaluate the usage of TBA method for the analysis of lipid peroxidation induced by streptozotocin. 5 mM streptozotocin and 1 % TBA alone showed the maximum peak at 309 nm and 358 nm respectively, although no peak was observed at 532 nm which was the wavelength to determine the absorbance for TBA method. When 5 mM streptozotocin was mixed together with 1 % TBA in vitro, new peaks at 439 nm and 532 nm had been detected, suggesting TBA did interact directly with streptozotocin forming new colored products. These results suggest that TBA method is not adequate for determination of lipid lperoxidation induced by streptozotocin.

• Journal of Korean Society of Environmental Engineers
• /
• v.38 no.12
• /
• pp.667-675
• /
• 2016

Nanoscale zero-valent iron (nZVI) has been effectively applied for environmental remediation due to its ability to reduce various toxic compounds. However, quantification of nZVI reactivity has not yet been standardized. Here, we adapted colorimetric assays for determining reductive activity of nZVIs. A modified indophenol method was suggested to determine reducing activity of nZVI. The method was originally developed to determine aqueous ammonia concentration, but it was further modified to quantify phenol and aniline. The assay focused on analysis of reduction products rather than its mother compounds, which gave more accurate quantification of reductive activity. The suggested color assay showed superior selectivity toward reduction products, phenol or aniline, in the presence of mother compounds, 4-chlorophenol or nitrobenzene. Reaction conditions, such as reagent concentration and reaction time, were optimized to maximize sensitivity. Additionally, pretreatment step using $Na_2CO_3$ was suggested to eliminate the interference of residual iron ions. Monometallic nZVI and bimetallic Ni/Fe were investigated with the reaction. The substrates showed graduated reactivity, and thus, reduction potency and kinetics of different materials and reaction mechanism was distinguished. The colorimetric assay based on modified indophenol reaction can be promises to be a useful and simple tool in various nZVI related research topics.

• Biomedical Science Letters
• /
• v.4 no.2
• /
• pp.103-112
• /
• 1998

We have developed a simple and accurate strip test that measures the blood glucose level semiquantitatively by visual observation, or qualitatively by using UltraScan spectrocolorimeter. The strip has solid phase reagents, including glucose oxidase, peroxidase, chromogen, affixed to a plastic support. The strip test is capable of measuring blood glucose level in the range of 0∼800 mg/dl and generating the results within 2 to 3 minutes. Human blood specimens obtained from normal individuals and the diabetic patients were evaluated by the new blood glucose strip and by the kit supplied by other commercial products. The test results exhibit the correlation coefficient of 0.964. The new test strip is proven simple and accurate, and it offers an alternative to the commercially available glucose tests.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 2005.11a
• /
• pp.299-300
• /
• 2005

본 연구에서는 $SiO_2$ 판상체 위에 저굴절 및 고굴절 금속 산화물을 다층 교차 증착하여 Pearl Pigment를 sputtering 공법을 이용하여 증착하였다. Pearl Pigment는 Essential Macleod program 을 이용한 색상과 증착된 pigment의 색상이 파장에 따라 blue, violet, pink, red, orange, yellow, green 등(Wave length : 450$\sim$730 nm)으로 동일하게 나타났고, 기존의 제품에 비해 색상효과가 뛰어나고, 표면 morphology가 우수하였다. 주사전자현미경(SEM)으로 막 두께, 표면 조직 및 입자 크기를 측정하였고, 스펙트로미터를 사용하여 각각의 파장을 분석하였으며 EDS, XRD를 이용하여 정성 및 정량 분석을 하였다.

• Proceedings of the Korean Society of Applied Pharmacology
• /
• 1993.04a
• /
• pp.60-60
• /
• 1993

새로운 항생물질을 개발하기 위하여 토양으로부터 분리한 균주를 액체배지에서 배양하여 그 배양액을 여러 검정균에 대하여 종이디스크법으로 항균효력을 측정하였다. 그 결과 G(＋), G(－)균에 강한 항균효력을 보인 토양균 SNUS 9101-55와 C. aibicans와 같은 진균류에 항균력을 보인 토양균 SN-US 9101-68을 선택하여 각각의 배양액에서 항생물질을 분리하고, 분리한 항생물질의 구조를 규명하고자 하였다. 토양균 SNUS 9101-55의 배양액으로부터 항생물질을 분리하기 위하여 양이온 교환수지 관 크로마토그래피와 셀룰로오스 관 크로마토그래피를 수행하여 시료 AMJ-I-212-B를 얻었다. 시료 AMJ-I-212-B의 IR, $^1$H-NMR, FAB-MS 스펙트럼을 얻어 분리한 항생물질의 구조를 분석하고 Sakaguchi test와 같은 정색반응을 통하여 그 발색단을 동정하여 이 항생물질의 구조가 스트렙토마이신과 동일하다는 것을 확인하였다.

• Analytical Science and Technology
• /
• v.13 no.5
• /
• pp.549-557
• /
• 2000

FRIR-ATR spectrometry has been used to monitor the aqueous reactions of compounds without distinct chromophores in ultraviolet and visible regions. For example, hydrolysis reactions of ${\alpha}$-cyclodextrin and ${\gamma}$-cyclodextrin in acidic aqueous solution were studied. FTIR-ATR method has been used for the monitoring of cyclodextrin hydrolysis in 1.0 M. 0.5 M, and 0.1 M HCl solutions, respectively. We also found that the hydrolysis of ${\alpha}$-cyclodextrin produced glucose, but the hydrolysis of ${\gamma}$-cyclodextrin proceeded further to give more fragmented products than glucose.