• Food Science and Biotechnology
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• 제18권6호
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• pp.1430-1434
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• 2009

The present study used the liquid extraction pretreatment method and developed a liquid chromatographyultraviolet detector (LC-UV) for the simultaneous determination of 14 sulfonamides (SAs) residues in porcine and chicken muscle. Linearity within a range of $50-150\;{\mu}g/kg$ was obtained with the correlation coefficient ($r^2$) of 0.9673-0.9997. The mean recovery of SAs was 55.9-109.7% (relative standard deviations; RSDs 1.7-17.3%) in porcine muscle and 52.8-112.4% (RSDs 2.3-16.9%) in chicken muscle. The limits of detection (LODs) and limits of quantification (LOQs) were 2-32 and $7-96\;{\mu}g/kg$ in porcine muscle, and 4-32 and $13-97\;{\mu}g/kg$ in chicken muscle, respectively. These values were lower than the maximum residue limits (MRLs) established by the European Union. The sum of all SAs residues present should be less than $100\;{\mu}g/kg$.

• 한국작물학회지
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• 제50권spc1호
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• pp.228-230
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• 2005

형광 염료와 레이저 겔스캐너 장비를 이용하여 변성아크릴 아마이드 겔에서 전기 영동된 DNA를 신속하고 간편한 방법으로 기존의 은염색법과 비슷한 감도로 검출하고자 하였다. 변성아크릴아마이드 겔을 형광 염료인 SYBR Green (Molecular Probes)이나 Vistra Green (Amersham Bioscience) 0.01 X 희석액 (pH 8)으로 염색한 후 480nm 레이져, 520nm filer 옵션으로 스캔하여 DNA를 검출하였으며, 검출감도는 기존의 은염색법과 비슷하면서 염색 단계를 한 단계로 줄일 수 있었다.

• Journal of Microbiology and Biotechnology
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• 제14권2호
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• pp.284-289
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• 2004

A PCR assay for the rapid detection of Vibrio vulnificus strains was developed using a virulence gene for elastase found in various Vibrio species. The DNA sequences in the elastase gene facilitated the identification of a species-specific probe for pathogenic V. vulnificus strains from both clinical and environmental sources. Using an elastase gene-based PCR reaction, a species-specific 507-bp PCR product was visualized by agarose gel electrophoresis. Three different DNA extraction methods were then compared to improve the simplicity and rapidity of detection. A PCR assay using the conventional DNA extraction or boiling method was able to detect as few as 25 V. vulnificus cells, making the detection limits at least 1-log-scale lower than that for the EDT A-treated DNA extraction method. In particular, the boiling method, which does not require purification of the chromosomal DNA, was very effective in terms of simple and rapid detection. Meanwhile, the detection limit in a mixed bacterial culture that included other bacteria, such as Escherichia coli or Bacillus subtilis, was two V. vulnificus cells, which was 1-log-scale lower than that for the control. Accordingly, when coupled with a new DNA extraction method, the elastase gene-based PCR can provide a rapid, specific, and sensitive method for identifying V. vulnificus in clinical and environmental samples.

• 분석과학
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• 제14권1호
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• pp.64-71
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• 2001

본 논문에서는 검출한계에 대한 기본개념을 기초로 백그라운드 측정시간과 시료측정시간을 고려한 검출한계치 유도과정을 기술하였다. 환경시료 중 Pu의 MDA값 결정에 영향을 미치는 여러인자들 중에서 시료량, 백그라운드 측정시간 및 시료측정시간 변화에 따른 MDA 변동값을 계산하였다. 환경시료에 대한 저준위 방사능 동위원소 측정시 본 연구결과를 통해 도출된 백그라운드 및 시료 측정시간의 적절한 배분에 의한 MDA 계산은 환경방사능 측정결과에 대한 신뢰도 평가에 활용이 가능하다.

• Bulletin of the Korean Chemical Society
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• 제33권7호
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• pp.2224-2228
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• 2012

This study describes the ability of capillary electrochromatography (CEC) for the determination of imidacloprid and carbendazim in tomato samples. A novel liquid crystal crown ether modified hybrid silica monolithic column was synthesized, characterized and developed as separation column for the first time. Baseline separation of imidacloprid and carbendazim could be achieved using a mobile phase containing 90% (v/v) 20 mmol/L phosphate buffer (pH 7.0) and 10% (v/v) acetonitrile. The matrix matched calibration curves were linear with correlation coefficient $r^2$ > 0.9998 in the range of 0.20-10.00 mg/L. The limits of detection for imidacloprid and carbendazim were 0.061 and 0.15 mg/kg, respectively, which were below the maximum residue limits established by the European Union as well as Codex Alimentarius. Average recoveries for imidacloprid and carbendazim varied from 101.6-108.0% with relative standard deviations lower than 6.3%. This method was applied to the analysis of tomatoes collected from local markets.

• Journal of Microbiology and Biotechnology
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• 제33권8호
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• pp.1101-1110
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• 2023

Streptococcus mutans is the primary causative agent of caries, which is one of the most common human diseases. Thus, rapid and early detection of cariogenic bacteria is critical for its prevention. This study investigated the combination of loop-mediated isothermal amplification (LAMP) and microfluid technology to quantitatively detect S. mutans. A low-cost, rapid microfluidic chip using LAMP technology was developed to amplify and detect bacteria at 2.2-2.2 × 10⁶ colony-forming units (CFU)/ml and its detection limits were compared to those of standard polymerase chain reaction. A visualization system was established to quantitatively determine the experimental results, and a functional relationship between the bacterial concentration and quantitative results was established. The detection limit of S. mutans using this microfluidic chip was 2.2 CFU/ml, which was lower than that of the standard approach. After quantification, the experimental results showed a good linear relationship with the concentration of S. mutans, thereby confirming the effectiveness and accuracy of the custom-made integrated LAMP microfluidic system for the detection of S. mutans. The microfluidic system described herein may represent a promising simple detection method for the specific and rapid testing of individuals at risk of caries.

• Natural Product Sciences
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• 제17권4호
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• pp.328-336
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• 2011

A high-performance liquid chromatography (HPLC) with diode array detector (DAD) method was established for the discrimination of a folk medicine Forsythia suspensa and Forsythia viridissima. Five and three representative metabolites of the lignan and phenolic glycoside classes were selected for the analysis from F. suspensa and F. viridissima, respectively. The optimal chromatographic conditions were obtained on an ODS column (5 ${\mu}m$, $4.6{\times}250$ mm) with the column temperature at $40^{\circ}C$. The mobile phase was composed of methanol and 0.3% acetic acid using an isocratic elution with the flow rate 1 mL/min. Detection wavelength was set at 280 nm. All calibration curves showed good linear regression ($r^2$ > 0.996) within test ranges. Limits of detection (LOD) and limits of quantitation (LOQ) values were lower than 0.096 and 0.291 ${\mu}g/mL$, respectively. The developed method provided satisfactory precision and accuracy with overall intra-day and inter-day variations of 0.07-0.63% and 0.14-0.62%, respectively, and the overall recoveries of 97.79-102.46% for all of the compounds analyzed. In addition, effectiveness of diverse extraction methods was compared to each other for the development of standard analytical method. The verified method was successfully applied to the quantitative determination of representative metabolites in fifty-three commercial F. suspensa samples and fifteen commercial F. viridissima samples from diverse sources. The overall analytical results showed the unequivocal differences in bioactive constituents between F. suspensa and F. viridissima.

• 한국추진공학회:학술대회논문집
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• 한국추진공학회 2004년도 제22회 춘계학술대회논문집
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• pp.802-806
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• 2004

For the protection of the local air quality and the global atmosphere, the emissions of trace species including nitric oxides (NO and NO$_2$) from gas turbines are regulated by local governments and by the International Civil Aviation Organization. In-situ measurements of such species are needed not only for the development of advanced low-emission combustion concepts but also for providing emissions data required for the sound assessment of the effects of the emissions on environment. We have been developing a laser absorption system that has a capability of simultaneous determination of NO and NO$_2$concentrations in the exhaust jets from aero gas turbines. A diode laser operating near 1.8 micrometer is used for the detection of NO while a separated visible tunable diode laser operating near 676 nanometers is used for NO$_2$. The sensitivities at elevated temperature conditions were determined for simulated gas mixtures heated up to 500K in a heated cell of a straight 0.5 m optical path. Sensitivity limits estimated as were 30 ppmv-m and 3.7 ppmv-m for NO and NO$_2$, respectively, at a typical exhaust gas temperature of 800K. Experiments using the simulated exhaust flows have proven that $CO_2$ and $H_2O$ vapor - both major combustion products - do not show any interference in the NO or NO$_2$ measurements. The measurement system has been applied to the NO/NO$_2$ measurements in NO and NO$_2$ doped real combustion gas jets issuing from a rectangular nozzle having 0.4 m optical path. The lower detection limits of the system were considerably decreased by using a multipass optical cell. A pair of off-axis parabola mirrors successfully suppressed the beam steering in the combustion gas jets by centralizing the fluctuating beam in sensor area of the detectors.

• 상하수도학회지
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• 제30권6호
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• pp.673-682
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• 2016

In this study, we investigated influent and effluent water pollutants in 53 Public Sewage Treatment Works (PSTWs) where industrial wastewater or landfill leachate is combined four times for two years from 2014 to 2015. Also, we analyzed the characteristics of heavy metals and volatile organic carbons at influent and effluent of these PSTWs caused by sewage treatment combined with industrial wastewater or landfill leachate. As a result, six heavy metals such as barium, copper, iron, manganese, nickel and zinc, and four volatile organic carbons (VOCs) including phenols, di(2-)ethylhexyl phthalate (DEHP), formaldehyde and toluene were observed above detection limits in most of PSTWs. Also, it was revealed that six heavy metals such as hexavalent chromium, mercury, cadmium, chromium, nickel and selenium, and four VOCs including 1,1-dichloroethylene, vinyl chloride, naphthalene, and epichlorohydrin were observed more frequently according to precipitation. As a result of reviewing the monitoring data on "Water Quality Monitoring Networks" in lower watersheds of PSTWs, both heavy metals and VOCs were below detection limits, indicating that the effluent water had little influence on the watershed. Nevertheless for the better management of influent and effluent pollutants in PSTWs, it is necessary to establish the advanced management plans for water pollutants in PSTWs, which include a list of priority substances management, monitoring plans, and guidelines for industrial wastewater and landfill leachate combined in PSTWs.

• 분석과학
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• 제14권2호
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• pp.115-122
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• 2001

우리나라 해안에 인접한 "K"지역 병원에서 구한 44명의 혈액에서 유기주석화합물인 mono-butyltin(MBT), dibutyltin(DBT) 그리고 tributyltin(TBT)을 불꽃광도검출기가 부착한 가스크로마토그라프로 분석하였다. 본 연구의 목적은 일부 주민의 혈액을 대상으로 MBT, DBT, TBT에 대한 분석방법과 농도를 고찰하는 것이다. 본 연구에서 이용한 분석방법에 대한 검출한계(method detection limit, MDL)는 MBT 3.67, DBT 0.91, TBT는 1.09ng Sn/g 습중량 기준으로 나타났다. 또한 일본 국립환경연구소가 제조한 농어중의 $1.3{\mu}g/g$ TBT as chloride의 농도가 가진 표준물질(standard reference material)을 분석한 결과 공인값과 잘 일치하였다. 혈액 중에서 검출된 농도의 범위는 MBT가 3.69-7.93ng Sn/g, DBT 1.15-5.41ng Sn/g이었고, TBT는 검출한계 미만 및 미검출이었다. 혈액중에서 검출된 MBT 및 DBT의 흡수와 축적은 사람들이 유기주석화합물이 생체축적된 수산물의 섭취, 각종 플라스틱류 사용 등에 원인이 있을 것으로 사료된다. 혈액중 유기주석화합물이 인체로 흡수되는 내재용량(internal dose)을 평가할 수 있는 지표서의 신뢰성에 관한 연구가 계속해서 진행되어야 할 것으로 판단된다.