• Bulletin of the Korean Chemical Society
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• v.32 no.11
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• pp.3959-3962
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• 2011

A simple propargylamide-fuctionalized chemodosimeter was prepared for the ratiometric fluorescence detection of mercuric ions in HEPES buffer. The chemodosimeter exhibited $Hg^{2+}$-induced propargyl amide-tooxazole transformation, with a significant accompanying ratiometric change in fluorescence. It afforded high selectivity for mercuric ion detection without any competitive inhibition by common alkali, alkaline earth, or other transition metal ions. The probe showed a $17{\times}10^{-6}M$ detection limit for $Hg^{2+}$ ions and potential applicability for detecting aqueous $Hg^{2+}$ ions.

• Bulletin of the Korean Chemical Society
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• v.35 no.2
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• pp.489-493
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• 2014

A phenylbenzimidazole derivatized sensor (L) that behaves as a ratiometric fluorescent receptor for $Zn^{2+}$ in water has been described. In HEPES buffer at pH 7.4, sensor L displays a weak fluorescence emission band at 367 nm. Upon addition of $Zn^{2+}$, the emission intensity at 367 nm is decreased, concomitantly, a new emission band centered at 426 nm is developed, thus facilitates a ratiometric $Zn^{2+}$ sensing behavior. Sensor L binds $Zn^{2+}$ through a 1:1 binding stoichiometry with high selectivity over other metal cations. Sensor L displays a linear response to $Zn^{2+}$ concentration from 0 to $6.0{\times}10^{-5}M$, sensor L also exhibits high sensitivity to $Zn^{2+}$ with a detection limit of $3.31{\times}10^{-7}M$.

• BMB Reports
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• v.35 no.4
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• pp.384-388
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• 2002

A method for the ratiometric pH sensing using LysoSensor DND-192 is presented in this paper. It works in the physiological pH range. It is based on the use of two fluorophores which differ significantly in their lifetimes. As the discrimination of their emissions is performed through two different frequencies, this method can allow significant overlap of the emission spectra. A simple long-pass filter, or a combination of long-and short-pass filters, was used instead of narrow-bandpass devices. Importantly, the measurements were carried out under strong ambient light. The method could be used in a wide variety of applications, such as intracellular measurements, microscopy, bioprocess monitoring, etc.

• Journal of Microbiology and Biotechnology
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• v.28 no.11
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• pp.1782-1790
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• 2018

Assessment of microorganism viability is useful in many industrial fields. A large number of methods associated with the use of fluorescent probes have been developed, including fluorimetry, fluorescence microscopy, and cytometry. In this study, a microvolume spectrofluorometer was used to measure the membrane potential variations of Escherichia coli. In order to estimate the sensitivity of the device, the membrane potential of E. coli was artificially disrupted using an ionophore agent: carbonyl cyanide 3-chlorophenylhydrazone. The membrane potential was evaluated using two ratiometric methods: a Rhodamine 123/4',6-diamidino-2-phenylindole combination and a JC-10 ratiometric probe. These methods were used to study the impact of freezing on E. coli, and were compared with the conventional enumeration method. The results showed that it was beneficial to use this compact, easy-to-use, and inexpensive spectrofluorometer to assess the viability of bacterial cells via their membrane potential.

• Bulletin of the Korean Chemical Society
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• v.34 no.1
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• pp.63-67
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• 2013

A bottom-modified (4-position) naphthalimide derivative 1 with 1,8-naphthyridine as binding site has been designed and synthesized. Compound 1 is the first 1,8-naphthyridine-modified naphthalimide-based sensor that can detect $Hg^{2+}$ selectively with respect to ratiometric fluorescent change and blue shift in organic aqueous solution. The Job's plot and FAB mass indicate that 1 formed a 1:1 complex with $Hg^{2+}$. A top-modified naphthalimide derivative 2 with 1,8-naphthyridin as binding site has also been synthesized for comparison.

• Rapid Communication in Photoscience
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• v.1 no.2
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• pp.60-60
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• 2012

• 한국가시화정보학회:학술대회논문집
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• 2004.12a
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• pp.91-110
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• 2004

A comprehensive three-dimensional nano-particle tracking technique in micro- and nano-scale spatial resolution using the Total Internal Reflection Fluorescence Microscope (TIRFM) is discussed. Evanescent waves from the total internal reflection of a 488nm argon-ion laser are used to measure the hindered Brownian diffusion within few hundred nanometers of a glass-water interface. 200-nm fluorescence-coated polystyrene spheres are used as tracers to achieve three-dimensional tracking within the near-wall penetration depth. A novel ratiometric imaging technique coupled with a neural network model is used to tag and track the tracer particles. This technique allows for the determination of the relative depth wise locations of the particles. This analysis, to our knowledge is the first such three-dimensional ratiometric nano-particle tracking velocimetry technique to be applied for measuring Brownian diffusion close to the wall.

• Bulletin of the Korean Chemical Society
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• v.30 no.1
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• pp.197-200
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• 2009

A simple dye having phenol and indole moieties was synthesized and its chromogenic signaling behaviors for the determination of water content in organic solvents were investigated. The compound revealed a pronounced chromogenic behavior in response to the variation of water content in water miscible aprotic organic solvents of acetone, acetonitrile, THF, and dioxane. Significant red shifts and changes in absorption spectra allowed a ratiometric analysis of the signaling behavior. The chemosensing behaviors were particularly pronounced in water content in less than 10% that is suitable for the application of the compound as a probe for the determination of water content in binary aqueous organic solutions having lower water content.

• Ocean and Polar Research
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• v.35 no.3
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• pp.229-237
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• 2013

We measured two-dimensional (2-D) oxygen distribution in the surface sediment layer of intertidal sediment using a simple and inexpensive planar oxygen optode, which is based on a color ratiometric image approach. The recorded emission intensity of red color luminophore light significantly changed with oxygen concentration by $O_2$ quenching of platinum(II)octaethylporphyrin (PtOEP). The ratios between the intensity of red and green emissions with oxygen concentration variation demonstrated the Stern-Volmer relationship. The 2-D oxygen distribution image showed microtopographic structure, diffusivity boundary layer and burrow in surface sediment layer. The oxygen penetration depth (OPD) was about 2 mm and the one-dimensional vertical diffusive oxygen uptake (DOU) was 12.6 mmol $m^{-2}d^{-1}$ in the undisturbed surface sediment layer. However, those were enhanced near burrow by benthic fauna, and the OPD was two times deeper and DOU was increased by 34%. The simple and inexpensive oxygen planar optode has great application potential in the study of oxygen dynamics with high spatiotemporal resolution, in benthic boundary layers.

• Bulletin of the Korean Chemical Society
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• v.31 no.1
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• pp.246-249
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• 2010