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온라인 사료주입과 UPLC-Orbitrap 질량분석법을 이용한 수질 조류독소의 고속분석방법 개발 및 환경시료적용
장제헌 ( Je Heon Jang ),김윤석 ( Yun Seok Kim ),최재원 ( Jae Won Choi ) 한국물환경학회 2012 한국물환경학회지 Vol.28 No.6
Due to the fast response to algae bloom issue in drinking water treatment plant, very fast determination methodology for algal toxin is required. In this study, column switching technique based online preconcentration method was combined with high resolution full scan mass spectrometer to save sample preparation time and to obtain fast and accurate result. After parameter optimization of online preconcentration, 1mL filtered sample was directly injected to trap column with switching valve system, Next, target toxins are eluted by 98% acetonitrile and analysed with 150-1,100 amu scan range at 50,000 resolving power. Method detection limit (MDL) for microcystin-LR, the most toxic isomer, was 0.1 ng/mL and others such as microcystin-YR, microcystin-RR and nodularin were 0.08, 0.03 and 0.04 ng/mL, respectively. This is the best improved sensitivities with 1mL volume in the literature. Furthermore, due to the use of ultra pressure HPLC (UPLC), the whole method run was completed in 4 min. Real sample applications for 173 sample including 55 surface water and 118 treatment plant samples for raw and treated water could be done within 16 hours. In our calculation, this methodology is roughly 80% faster than the previous manual solid-phase extraction with LC-MS/MS method.
한강수계 하천수의 카바메이트계 농약 모니터링(2007~2009)
장제헌 ( Je Heon Jang ),김정희 ( Jeong Hee Kim ),최재원 ( Jae Won Choi ),오은정 ( Eun Jeong Oh ),노혜란 ( Hye Ran Noh ) 한국환경분석학회 2010 환경분석과 독성보건 Vol.13 No.1
Simultaneous analytical methods for the nine carbamate families such as aldicarb sulfoxide, aldicarb sulfone, oxamyl, methomyl, 3-hydroxy carbofuran, aldicarb, propoxur, carbofuran and carbaryl were optimized using high performance liquid chromatograph with flouresence detector (HPLC/FLD). All the target compounds including internal standard (4-bromo-3,5-dimethylphenyl-N-methylcarbamate, BDMC) detected within 31 min. Linearity of calibration standards for all compounds between 0.5 and 20 μg/L were above >0.999. The recoveries and the relative standard deviations (RSDs) of spiked samples with 0.5~1.0 μg/L were in the ranges of 83.9~111.3% and 4.8~10.5%, respectively. Method detection limits(MDLs) for nine carbimate and related compounds were 0.07~0.34 μg/L. The optimized method was applied to the surface water samples from Han River during 2007~2009. Carbofuran, methomyl and some family compounds were detected in traceable levels with very low frequencies. Therefore, there seems to be very low exposure risks of carbamate and related pesticides in Han River area.
중집광형 태양광 집광장치 용 선형 프레넬 렌즈의 최적화설계연구
송제헌,유진희,이준호,장원근,이동길,Song, Je Heon,Yu, Jin Hee,Lee, Jun Ho,Jang, Won Keun,Lee, Dong Gil 한국광학회 2013 한국광학회지 Vol.24 No.5
본 논문에서는 25배 태양광 집광장치에 적용될 선형 프레넬 렌즈의 최적화에 대해 서술한다. 이 선형 프레넬 렌즈는 각기 다른 패턴을 가진 $10{\times}10$ mm 크기의 선형 프레넬 렌즈가 $5{\times}5$의 형태로 결합된 렌즈이다. 각 프레넬 렌즈는 같은 크기의 태양전지로 태양광이 입사할 수 있도록 최적화되어 있다. 최적화된 프레넬 렌즈의 설계치는 패턴높이 35 ${\mu}m$, 구배각 $4^{\circ}$, 모서리 라운드 1 ${\mu}m$로 각각의 선형 프레넬 렌즈에 모두 같은 값이 부여되었지만 사면경사각은 $14.1^{\circ}{\sim}31.2^{\circ}$로 각기 다르다. 이렇게 설계된 선형 프레넬 렌즈의 태양광 집광효율은 80%이상이며 기존의 25배 집광용 단일 프레넬 렌즈보다 오정렬 및 제작공차 측면에서 강력한 성능을 가진다. 설계된 선형 프레넬 렌즈의 민감도 분석을 통해 모서리 라운드가 1 ${\mu}m$씩 증가할수록 집광효율이 ~5%씩 저하되는 것을 파악하였고 이에 모서리 라운드가 최소한의 수치로 유지되어야 함을 확인하였다. This paper presents a combination of linear Fresnel lenses optimized for ${\times}25$ solar concentration. The combined lens consists of $5{\times}5$ linear Fresnel lenses. Each Fresnel lens is of $10{\times}10$ mm and optimized to tilt the incoming light onto a solar cell of the same size. All of the optimized Fresnel segments have the same pattern height of 35 ${\mu}m$, draft angle of $4^{\circ}$, and edge groove round of 1 ${\mu}m$ but with different facet angles varying from $14.1^{\circ}$ to $31.2^{\circ}$. The solar concentrating efficiency of the combination is shown to be over 80% and more robust than a conventional single ${\times}25$ circular Fresnel lens in terms of pointing misalignment and manufacturing errors. A sensitivity analysis finds that the edge groove round should be kept as small as machining allows since the concentrating efficiency drops ~5% per 1 ${\mu}m$ increase of the edge groove.
액체크로마토그래피-텐덤질량분석법에 의한 하천수 및 정수 중 남세균기원 독소 실린드로스퍼몹신(Cylindrospermopsin)의 정량분석
최재원,장제헌,이선홍,윤미애 한국환경분석학회 2022 환경분석과 독성보건 Vol.25 No.2
Cylindrospermopsin (CYN) is an emerging freshwater cyanobacterial toxin, and its reports on toxicity toward the human liver and kidney tissues has drawn a lot of attention. An appropriate analytical method is necessary to determine the presence of this emerging cyanobacterial toxin in water resources including drinking water; therefore, it is necessary to develop a sensitive analytical method for CYN detection. In this study, we developed a simple and sensitive analytical method for CYN detection using liquid chromatography-tandem mass spectrometry (LC-MS/MS) using direct injection. The method was validated for linearity of calibration, limit of detection, limit of quantitation, accuracy, and precision. The limit of detection and quantitation were in the range of 0.029 μg/L and 0.091 μg/L, respectively. Accuracy and precision were also obtained within an acceptable range. The optimized method was used to measure the concentrations of CYN in the surface water from each weir areas of the Geum River, Nakdong River. Additionally, this method was applied to samples of drinking water obtained from the treatment plants of the Geum River, Nakdong River for each process.
실시간 이온화 소스(DART) 및 오비트랩 질량분석방법을 연계한 농약류의 신속,정확한 정성 방법
최원석 ( Won Seok Choi ),장제헌 ( Je Heon Jang ),김윤덕 ( Yun Duck Kim ),최재원 ( Jae Won Choi ) 한국환경분석학회 2012 환경분석과 독성보건 Vol.15 No.4
It must be immediate ready for possible chemical terrorism that might range from water or food contamination. In April 2012, there has been real pesticide attack in small scale drinking water facility at Hongsung area. Early detection of any terrorism is dependent on a strong public health system. The objective of this study was to develop a high-speed and accurate analytical method to identify pesticides in water using direct analysis in real time (DART) ionization and accurate mass scanning by Orbitrap mass spectrometry. Ionization temperature and time for DART were set at 300℃ and 30 s, respectively. Resolution, scan range and mass accuracy for Orbitrap mass spectrometry were operated at 50,000, 100∼500 and 5 ppm, calculted parts per million unit of monoisotope, respectively. Xcalibur 2.1 was used for identification and mass accuracy test. Protonated molecular ions and carbon or chlorine isotopes for tested compounds were identified within 1 ppm mass accuracy. Acetochlor (C_14H_20ClNO_2) was randomly selected for sensitivity test. Protonated molecular ion m/z 270.1258 and chlorine isotope for identification m/z 272.1231 were detected with ratio of 3:1 for 100 to 1 ng/mL. This indicated that this approach is a sensitive and available direct analysis without sample preparation in case of urgent accidents.