• 한국수산과학회지
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• 제53권2호
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• pp.174-180
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• 2020

The mouse bioassay has been used widely for the monitoring of paralytic shellfish toxins (PSTs) in many countries. However, this method shows low sensitivity and high limit of detection (LOD), as well as it cannot confirm toxic profiles. Recently, LC-MS/MS method was studied for the quantitative of PSTs, however, the method has any problems with unstable retention times by ionization suppression caused by high salt concentration in shellfish extracts. To establish an alternative method for PSTs analysis, we tried to original LC-MS/MS methods adding desalting operation using amorphous graphitized polymer carbon solid-phase extraction cartridges. The method validation was conducted to determine linearity, limit of detection, limit of quantification (LOQ), accuracy, and precision in quantifying PSTs. The correlation coefficients for all tested PSTs maintained over 0.999. The LODs and LOQs for all PSTs were about 0.19-1.05 ㎍/kg and 0.58-3.18 ㎍/kg, respectively. The accuracies for PSTs were 95.4-107.7% for saxitoxin group, 97.1-100.9% for gonyautoxin group, 99.0-100.8% for N-sulfocarbamoyl toxin group, and 96.8-104.6% for decarbamoyl toxin group. These results indicate that the modified LC-MS/MS method was appropriate for analyzing the PSTs in shellfish and tunicates.

• Journal of Microbiology and Biotechnology
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• 제25권11호
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• pp.1782-1786
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• 2015

A new improved PCR method has been developed for the rapid, reliable, and sensitive detection of Venturia nashicola, a destructive pathogen of scab disease in Japanese pear. The translation elongation factor-1 alpha gene-derived PCR primers specifically amplified a 257-bp-sized DNA band of the target gene from the genomic DNA of V. nashicola. No amplicon was produced from the genomic DNA of other Venturia spp. and reference fungal species tested. With the high detection limit of 10 fg DNA content, our real-time method could be used for the quarantine inspection and field monitoring of V. nashicola.

• Journal of Electrochemical Science and Technology
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• 제5권1호
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• pp.19-22
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• 2014

Here we report a highly sensitive and stable detection of $NAD^+$ and NADH by the electrode on which diaphorase (DI) is covalently immobilized in viologen polymer network. The network is prepared by the covalent formation of the structure by mixing propylamine viologen (PAV), poly(ethylene glycol)(400) diglycidyl ether (PEGDGE), an diaphorase (DI). The PAV/PEGDGE/DI modified electrode has the sensitivity of $0.02nA{\cdot}{\mu}M$ and the detection limit of $3{\mu}M$ with a response time of 2 s ($t_{90%}$) for NADH sensing.

• Journal of the Optical Society of Korea
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• 제20권6호
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• pp.669-677
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• 2016

A miniaturized FTIR spectrometer based on lamellar grating interferometry is being developed for passive remote-sensing. Consisting of a pair of micro-mirror arrays, the lamellar grating can be fabricated using MEMS technology. This paper describes a method to compute the optical field in the interferometer to optimize the design parameters of the lamellar grating FTIR spectrometer. The lower limit of the micro-mirror width in the grating is related to the formation of a Talbot image in the near field and is estimated to be about $100{\mu}m$ for the spectrometer to be used for the wavelength range of $7-14{\mu}m$. In calculating the far field at the detection window, the conventional Fraunhofer equation is inadequate for detection distance of our application, misleading the upper limit of the micro-mirror width to avoid interference from higher order diffractions. Instead, the far field is described by the unperturbed plane-wave combined with the boundary diffraction wave. As a result, the interference from the higher order diffractions turns out to be negligible as the micro-mirror width increases. Therefore, the upper limit of the micro-mirror width does not need to be set. Under this scheme, the interferometer patterns and their FT spectra are successfully generated.

• 대한화학회지
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• 제61권4호
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• pp.139-142
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• 2017

Ethene ($C_2H_4$), which is produced in plants as they mature, was used to study its photoacoustic properties using photoacoustic spectroscopy. Detection of trace amounts, with $N_2$ gas, of $C_2H_4$ gas was also applied. The gas was tested in various conditions-temperature, concentration of the gas, gas cell length, and power of the laser- to determine their effect on the photoacoustic signal, the ideal conditions to detect trace gas amounts, and concentration of $C_2H_4$ produced by an avocado and a banana. A detection limit of 10 ppm was determined for pure $C_2H_4$. A detection of 5% and 13% (by volume) concentration of $C_2H_4$ was produced for a ripening avocado and banana, respectively, in closed space.

• Bulletin of the Korean Chemical Society
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• 제34권2호
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• pp.595-599
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• 2013

The coordination of pyridyl-N to pentacyanoferrate for the detection of small organic antigens in solution is presented. The unique contribution of this paper is the direct conjugation of pyridyl-N in small organic antigens to pentacyanoferrate. Pentacyanoferrate is promising as an electrochemical label owing to its good electro-chemical properties, which can be utilized to generate an electrical signal in homogeneous electrochemical immunoassays. The facilely synthesized pyridyl-N to pentacyanoferrate was characterized by the electrochemical and spectroscopic methods. Hippuric acid (HA) has been detected competitively on the interaction of free HA and pentacyanoferrate-(4-aminomethylpyridine-hippuric acid) (Fe-HA) to its antibody, with the detection limit of 0.50 ${\mu}g\;mL^{-1}$. While pentacyanoferrate-based immunoassay is in its simplicity and infancy, the proposed immunoassay offers attractive opportunities for developing pyridyl-N-based the electrochemical detection of small organic antigens in the health care area.

• 한국식품위생안전성학회지
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• 제22권4호
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• pp.370-374
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• 2007

본 논문에서는 테트라사이클린(TCs)계 항생물질 4종(옥시테트라사이클린, 테트라사이클린, 클로르테트라사이클린, 독시사이클린)에 대하여, 액-액 추출 과정을 거쳐서 자외선검출기가 장착된 액체크로마토그래피를 이용하여 계란 중에서 TCs를 효율적으로 분석하는 방법을 확립하였다. 컬럼은 Zorbax Eclipse XDB-C8$(150mm{\times}4.6mm,\;5{\mu}m)$, 이동상 용매는 20 mM oxalic acid(pH 1.5), acetonitrile로 기울기 용리를 사용하였으며, 검출파장은 360 nm로, 그리고 유속은 1.0 ml/min, 주입량은 10 ml로 설정하여 분석하였다. 확립된 분석조건으로, TCs 4종에 대한 표준검정 곡선은 $50-800{\mu}g/kg$의 농도범위에서 상관계수가 0.994이상의 양호한 직선성을 나타내었다. 회수율은 $50-800{\mu}g/kg$의 농도범위에서 79.6-109.3%로, 향상된 추출효율을 나타내었으며, 검출한계는 $30{\mu}g/kg$이었고, 정량한계는 $50{\mu}g/kg$으로서 MRL/4 수준 이하까지는 충분히 검출 가능하였다. 또한, 일내(intra-day)와 일간(inter-day) 정밀도(RSD)는 0.1-10.9%, 1.1-13.7%이었다. 따라서, 확립된 분석방법은 계란 중의 TCs을 효과적으로 분석하는데 이용될 수 있을 것으로 사료된다.

• Corrosion Science and Technology
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• 제10권4호
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• pp.151-155
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• 2011

The iron oxide particles could be resulted from the corrosion of the circulating water system of a power plant. Because it may be one of the trouble materials which affect the power generation efficiency due to the deposition on steam generator tube and turbine blade, the continuous observation of its concentration is very important. The laser induced break-down detection (LIBD) technology was applied to monitor continuously the concentration of corrosion products with the detection limit of ppb level. The measurement system consists of a Nd:YAG pulsed laser, a polarizing beam splitter, a flow-type sample cell, an acoustic emission sensor, a high speed data acquisition board, a personal computer, etc.. The performance test results confirmed that this technology can be effective to monitor the corrosion product concentration of the circulating water system of a power plant.

• 분석과학
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• 제36권4호
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• pp.161-169
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• 2023

In this study, a straightforward and precise nitrogen/sulphur-codoped carbon dots (N/S-CD) was produced using a microwave irradiation approach. The N/S-CD was formulated from succinic acid (SA), bis-(3-aminopropyl)-amine (BAPA), and sodium thiosulphate (STS) as sources of carbon, nitrogen, and sulphur, respectively. The synthesized N/S-CD established a valuable quantum yield (QY) of 70 % and was sensitive to aluminium ion (Al³⁺) with a detection limit of 0.21 µM and a linear concentration range of 0-100 µM. When detecting Al³⁺ in real water samples, the N/S-CD resulted in a satisfactory recovery in the range of 91.14 %-103.37 %. Thus, the proposed study is very promising for Al³⁺ detection in environmental water samples.

• Fisheries and Aquatic Sciences
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• 제4권1호
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• pp.32-38
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• 2001

Several molecular biological techniques have been used to detect virus rapidly and accurately, but these methods have limitations in the early stage of viral infection with very low concentration of virus. We compared the detection limits of IMS-PCR, Western blot and ELISA with infectious hematopoietic necrosis virus OHNV). Four antibodies, rabbit anti-IHNV polyclonal antibody, anti-IHNV nucleocapsid protein monoclonal antibody, anti-IHNV nucleocapsid protein polyclonal antibody, and anti-IHNV glycoprotein polyclonal antibody, were tested to find out the most effective antibody for each method. The detection limit with IMS- PCR was $2\times10^6$ pfu when the viral RNA was extracted before RT-PCR. In the western blot with rabbit anti­IHNV polyclonal antibody one pfu of virus could be detected. In ELISA, 10 pfu of virus particles were detected with the same antibody.