• Proceedings of the Korean Environmental Sciences Society Conference
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• 2005.05a
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• pp.419-421
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• 2005

• Journal of Environmental Science International
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• v.29 no.2
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• pp.201-207
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• 2020

A new chemosensor based on a self-assembled system has been devised to detect Hg²⁺ions efficiently. We demonstrated that the amphiphilic building blocks consisting of pyrene and boronic acid (1) aggregate in aqueous solutions and provide an outstanding sensing platform for sensitive detection. The self-assembled 1 exhibited high selectivity and sensitivity for Hg²⁺ion detection via fluorescence quenching, where the Hg²⁺ion detection ensued from a fast transmetallation of 1. The Stern-Volmer (SV) quenching constant for its fluorescence quenching by Hg²⁺ions was approximately 1.58 × 10⁸ M^-1. In addition, self-assembled 1 exhibited excellent sensing abilities at nano-molar concentration levels when tap water and freshwater samples were contaminated with of Hg²⁺ ions.

• Journal of Sensor Science and Technology
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• v.14 no.5
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• pp.308-312
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• 2005

We present a microfluidic chip designed for the detection of antibody by using quantum dots fluorescence and a microbead-based assay. A custom designed PDMS microfluidic chip with multi-layer channel is utilized for capturing microbeads; antibody injection into each micro-well; QD injection; and fluorescence detection. The experiment using the fabricated microfluidic chip has been performed on solutions with various concentrations of antibody and has shown correlated fluorescent intensities.

• 한국생물공학회:학술대회논문집
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• 2005.04a
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• pp.93-94
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• 2005

• Journal of Sensor Science and Technology
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• v.31 no.4
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• pp.266-270
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• 2022

Owing to the rising volume of seaborne trade, oil spills damage the marine environment for over 250 yearly. Thus, various analysis methods such as the Fourier-transform infrared (FTIR), Raman spectroscope, and gas chromatography are used to monitor oil spills at sea, but these methods are expensive. Recently, to reduce operational costs, an underwater fluorometer was adopted. However, this approach is not ideal for the remote sensing of oil spills because the device gets submerged in the sea. In this study, we have designed and developed a monitoring system that uses ultraviolet fluorescence to detect spilled oil or water from a distance, as well as proposed an analyzing method defining based on water Raman signal and QF535. Each fluorescence spectrum of water, oil (crude oil), and Bunker A was obtained using the system, and was calculated and analyzed from the spectrum individually. Based on the results of the analysis, we could successfully identity water and oil at a long distance.

• Bulletin of the Korean Chemical Society
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• v.34 no.12
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• pp.3681-3689
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• 2013

This study explored a direct SET-photochemical strategy to construct a new family of thioene conjugated-naphthalamide fluorophore based lariat-crown ethers which show strong binding properties towards heavy metal ions. Irradiations of designed nitrogen branched (trimethylsilyl)methylthio-terminated polyethylenoxy-tethered naphthalimides in acidic methanol solutions have led to highly efficient photocyclization reactions to generate naphthalamide based lariat type thiadiazacrown ethers directly in chemo- and regio-selective manners which undergo very facile secondary dehydration reactions during separation processes to produce their corresponding amidoenethio ether cyclic products tethered with electron donating diethyleneoxy- and diethyenethio-side arm chains. Fluorescence and metal cation binding properties of the lariat type enamidothio products were examined. The photocyclized amidoenethio products, thioene conjugated naphthalamide fluorophore containing lariat-thiadiazacrowns exhibited strong fluorescence emissions in region of 330-450 nm along with intramolecular exciplex emissions in region of 450-560 nm with their maxima at 508 nm. Divalent cation $Hg^{2+}$ and $Pb^{2+}$ showed strong binding to sulfur atom(s) in side arm chain and atoms in enethiadiazacrown ether rings which led to significant enhancement of fluorescence from its chromophore singlet excited state and concomitant quenching of exciplex emission. The dual fluorescence emission responses towards divalent cations might provide a new guide for design and development of fluorescence sensors for detecting those metals.

• Membrane Journal
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• v.31 no.2
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• pp.87-100
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• 2021

With a striking increase in the level of contamination and subsequent degradations in the environment, detection and monitoring of contaminants in various sites has become a crucial mission in current society. In this review, we have summarized the current research areas in membrane-based colorimetric sensors for trace detection of various molecules. The researches covered in this summary utilize membranes composed of cellulose fibers as sensing platforms and metal nanoparticles or fluorophores as optical reagents. Displaying decent or excellent sensitivity, most of the developed sensors achieve a significant selectivity in the presence of interfering ions. The physical and chemical properties of cellulose membrane platforms can be customized by changing the synthesis method or type of optical reagent used, allowing a wide range of applications possible. Membrane-based sensors are also portable and have great mechanical properties, which enable on-site detection of contaminants. With such superior qualities, membrane-based sensors examined in the researches were used for versatile purposes including quantification of heavy metals in drinking water, trace detection of toxic antibiotics and heavy metals in environmental water samples. Some of the sensors exhibited additional features like antimicrobial ability and recyclability. Lastly, while most of the sensors aimed for a detection enabled by naked eyes through rapid colour change, many of them investigated further detection methods like fluorescence, UV-vis spectroscopy, and RGB colour intensity.

• KSBB Journal
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• v.20 no.4
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• pp.291-298
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• 2005

Two-dimensional (2D) spectrofluorometer is often used to monitor various fermentation processes. The change in fluorescence intensities resulting from various combinations of excitation and emission wavelengths is investigated by using a spectra subtraction technique. But it has a limited capacity to classify the entire fluorescence spectra gathered during fermentations and to extract some useful information from the data. This study shows that the self-organizing map (SOM) is a useful and interpretative method for classification of the entire gamut of fluorescence spectral data and selection of some combinations of excitation and emission wavelengths, which have useful fluorometric information. Some results such as normalized weights and variances indicate that the SOM network is capable of interpreting the fermentation processes of S. cerevisiae and recombinant E. coli monitored by a 2D spectrofluorometer.

• Journal of the Korean Society for Marine Environment & Energy
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• v.18 no.4
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• pp.304-309
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• 2015

To evaluate the degree of contamination caused by oil spill accident in the sea, the in-situ sensors which are based on the scientific method are needed in the real site. The sensors which are based on the fluorescence detection theory can provide the useful data, such as the concentration of oil. However these kinds of sensors commonly are composed of the ultraviolet (UV) light source such as UV mercury lamp, the multiple excitation/emission filters and the optical sensor which is mainly photomultiplier tube (PMT) type. Therefore, the size of the total sensing platform is large not suitable to be handled in the oil spill field and also the total price of it is extremely expensive. To overcome these drawbacks, we designed the fluorimeter for the oil spill detection which has compact size and cost effectiveness. Before the detail design process, we conducted the experiments to measure the excitation and emission spectrum of oils using five different kinds of crude oils and three different kinds of processed oils. And the fluorescence spectrometer were used to analyze the excitation and emission spectrum of oil samples. We have compared the spectrum results and drawn the each common spectrum regions of excitation and emission. In the experiments, we can see that the average gap between maximum excitation and emission peak wavelengths is near 50 nm for the every case. In the experiment which were fixed by the excitation wavelength of 365 nm and 405 nm, we can find out that the intensity of emission was weaker than that of 280 nm and 325 nm. So, if the light sources having the wavelength of 365 nm or 405 nm are used in the design process of fluorimeter, the optical sensor needs to have the sensitivity which can cover the weak light intensity. Through the results which were derived by the experiment, we can define the important factors which can be useful to select the effective wavelengths of light source, photo detector and filters.

• Textile Coloration and Finishing
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• v.30 no.2
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• pp.63-69
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• 2018

In this study, we report on successful attempt towards the synthesis of sulfur self-doped $g-C_3N_4$ by directly heating thiourea in air. The synthesized materials were characterized using UV-vis spectral technique, FT-IR, XRD and TEM analysis. Further, the obtained material shows an excellent detection of carcinogenic TNP(Tri nitro phenol) in the presence of 10-fold excess of various other common interferences. The strong inner filter effect and molecular interactions(electrostatic, ${\pi}-{\pi}$, and hydrogen bonding interactions) between TNP and the $S-g-C_3N_4$ Nano sheets led to the fluorescence quenching of the $S-g-C_3N_4$ Nano sheets with an excellent selectivity and sensitivity towards TNP compared to that of other nitro aromatics under optimal conditions and the detection limit calculated was found to be 6.324 nM for TNP. The synthesized nanocomposite provides a promising platform for the development of sensors with improved reproducibility and stability for ultra-sensitive and selective sensing of TNP.