• 한국지하수토양환경학회:학술대회논문집
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• 한국지하수토양환경학회 2004년도 총회 및 춘계학술발표회
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• pp.370-375
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• 2004

KMnO$_4$에 의한 TCE 용액의 분해에서 Headspace를 가진 반응 용기는 liquid sample을 headspce의 관측값으로 반응의 특성을 나타낼 수 없다. 이런 특성에 의해 in-situ KMnO$_4$ 이용은 TCE의 제거 효율에서 자연적인 휘발을 고려해야한다. 1:2.45 몰비에서 liquid sample의 결과 반감기는 약 80분이고 160분에 약 67%의 제거율을 보인다. 1:12.27 몰비의 경우 반감기는 10분이고 90분에 95%의 제거효율을 보인다.

• Asian Journal of Atmospheric Environment
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• 제11권1호
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• pp.54-60
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• 2017

Quantifying the trace elements in infinitesimal ambient liquid samples (e.g., single raindrop, cloud/fog water, and the soluble fraction extracted from the particles collected for a short time) is an important task for understanding formation processes, heating/cooling rates, and their health hazards. The purpose of this study is to employ an in-air micro PIXE system for quantitative analysis of the trace elements in a thimbleful of reference liquid sample. The bag type liquid sample holder originally designed with $10{\mu}m$ thick $Mylar^{(R)}$ film retained the original shape without any film perforation and apparent peaks of film blank by the end of the analysis. As one of tasks to be solved, the homogeneity of the elemental distribution in liquid reference species was verified by the X-ray line profiles for several references. It was possible to resolve the significant peaks for whole target elements corresponding to the channel number of micro-PIXE spectrum. The calibration curves for the six target elements (Si, S, Cl, Fe, Ni, and Zn) in standard solutions were successfully plotted by concentration (ppm) and ROI of interest net counts/dose (nC).

• Bulletin of the Korean Chemical Society
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• 제26권6호
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• pp.947-951
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• 2005

Rotating compensator multichannel spectroscopic ellipsometry has been employed to determine the optical functions of various liquids used in chemistry. We attempted three different measurement configurations: (1) air-liquid interface, (2) prism-liquid interface, and (3) liquid-sample interface. In prism-liquid interface, we found that the prism surface had roughness and it should be considered in analysis for accurate results. In liquidsample interface, we had much higher reflection, better sensitivity, and less limitation compared to the other two configurations when crystalline silicon was used as reference sample. We discuss the merit of each configuration and present the optical functions of various liquids. Also we demonstrate Bruggeman effective medium theory to determine the optical properties of mixed liquid.

• Mass Spectrometry Letters
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• 제7권1호
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• pp.26-29
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• 2016

Simultaneous determination of three corticosteroids (clobetasol propionate, betamethasone dipropionate, fluticasone propionate) in moisturizers was performed by using liquid chromatography (LC) coupled with tandem mass spectrometry (MS/MS). Sample preparation was conducted by the liquid-liquid extraction (LLE). Moisturizers include emulsifying agent and it forms micelles. In order to improve the extraction efficiency of corticosteroids trapped in micelle, newly developed-optimized extraction conditions which can remove the matrix effect from moisturizers was applied with various pH conditions in LLE extraction stage of sample preparation. Thus, the addition of 10 μL of 1 M HCl into moisturizers sample before extraction could improve the extraction efficiency. For the quantitative analysis, SRM table that contained specific transition of all of target corticosteroids was created. The developed method was validated for linearity, accuracy, precision, limit of detection (LOD), limit of quantization (LOQ) and recovery. Over the 0.99 r² value was obtained in calibration standard range. Effective accuracy and precision were also obtained. LODs were below 31 ng/mL and LOQs were estimated below 94 ng/mL for all corticosteroids tested.

• 분석과학
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• 제29권1호
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• pp.29-34
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• 2016

염소로 소독된 음용수에서 수백 ng/L의 농도까지 검출되는 3-chloro-4-(dichloromethyl)-5-hydroxy-2(5H)-furanone(MX)를 시료 농축 후 액-액 추출(LLE), 메틸 유도체화 및 GC-MS로 정량 분석하였다. 4 L의 물 시료를 감압회전증발기를 사용해 30 ℃에서 0.4 L로 농축하였다. 물 중의 MX는 ethyl acetate(100 mL × 2)를 용매로 사용하여 추출하였으며, 추출액 중 MX는 10 % H₂SO₄ in methanol로 methyl 유도체를 만들었다. MX의 회수율은 73.8 %이었으며, 이는 수지 흡착법의 38.1 %보다 높았다. 정량한계와 반복성(RSD)은 각각 10 ng/L와 2.2 %로 추정되었다. 이 결과는 시간이 더 많이 소요되는 수지 흡착법의 대체 방법으로 LLE가 사용될 수 있다는 것을 보여 주었다.

• Bulletin of the Korean Chemical Society
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• 제27권2호
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• pp.231-236
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• 2006

A novel sample pretreatment technique, headspace hanging drop liquid phase microextraction (HS-LPME) was studied and applied to the determination of flavors from solid clove buds by gas chromatography-mass spectrometry (GC-MS). Several parameters affecting on HS-LPME such as organic solvent drop volume, extraction time, extraction temperature and phase ratio were investigated. 1-Octanol was selected as the extracting solvent, drop size was fixed to 0.6 $\mu$L. 60 min extraction time at 25 ${^{\circ}C}$ was chosen. HS-LPME has the good efficiency demonstrated by the higher partition equilibrium constant ($K_{lh}$) values and concentration factor (CF) values. The limits of detection (LOD) were 1.5-3.2 ng. The amounts of eugenol, $\beta$-caryophyllene and eugenol acetate from the clove bud sample were 1.90 mg/g, 1.47 mg/g and 7.0 mg/g, respectively. This hanging drop based method is a simple, fast and easy sample enrichment technique using minimal solvent. HSLPME is an alternative sample preparation method for the analysis of volatile aroma compounds by GC-MS.

• Bulletin of the Korean Chemical Society
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• 제31권10호
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• pp.2813-2818
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• 2010

A novel method was developed for the speciation of chromium in natural water samples based on homogeneous liquid-liquid extraction and determination by flame atomic absorption spectrometry (FAAS). In this method, Cr(III) reacts with a new Schiff's base ligand to form the hydrophobic complex, which is subsequently entrapped in the sediment phase, whereas Cr(VI) remained in aqueous phase. The Cr(VI) assay is based on its reduction to Cr(III) by the addition of sodium sulfite to the sample solution. Thus, separation of Cr(III) and Cr(VI) could be realized. Homogeneous liquid-liquid extraction based on the pH-independent phase-separation process was investigated using a ternary solvent system (water-tetrabutylammonium ion ($TBA^+$)-chloroform) for the preconcentration of chromium. The phase separation phenomenon occurred by an ion-pair formation of TBA and perchlorate ion. Then sedimented phase was separated using a $100\;{\mu}L$ micro-syringe and diluted to 1.0 mL with ethanol. The sample was introduced into the flame by conventional aspiration. After the optimization of complexation and extraction conditions such as pH = 9.5, [ligand] = $1.0{\times}10^{-4}\;M$, [$TBA^+$] = $2.0{\times}10^{-2}\;M$, [$CHCl_3$] = $100.0\;{\mu}L$ and [$ClO_4$] = $2.0{\times}10{-2}\;M$, a preconcentration factor (Va/Vs) of 100 was obtained for only 10 mL of the sample. The relative standard deviation was 2.8% (n = 10). The limit of detection was sufficiently low and lie at ppb level. The proposed method was applied for the extraction and determination of chromium in natural water samples with satisfactory results.

• 대한수의학회지
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• 제43권3호
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• pp.393-398
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• 2003

Simple and rapid sample preparation method for trace elements in foods of animal origin using ultra high pressure microwave digestion system (UHP/MDS) and inductively coupled plasma atomic emission spectrometer (ICP/AES) were developed. 1. For the digestion of sample using UHP-MDS, 20% nitric acid (v/v) was the most suitable solvent for the determination of trace elements in foods of animal origin. 2. The optimal digestion conditions for UHP-MDS were as follows: final temperature $180^{\circ}C$, final pressure 400 PSI, and magnetic power 900 W in the solid sample. For the liquid sample final temperature $170^{\circ}C$, final pressure 300 PSI and magnetic power 700 W were optimal conditions. 3. As result of interlaboratory test, the average recovery rate of the for solid sample were 88.3~99.1% for As, 82.4~93.3% for Cd, 89.2~101.2% for Hg and 86.5~93.8% for Pb, respectively. In liquid sample, it were 87.0~96.8% for As, 80.9~96.6% for Cd, 87.5~91.2% for Hg and 91.4~95.5% for Pb, respectively. 4. The average coefficient variation rate were 3.3~15.9% for solid sample and 2.9~10.8% for liquid sample.

• 한국동물위생학회지
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• 제36권4호
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• pp.273-281
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• 2013

This study investigated the effects of the alkaline detergent and acid rinse used for cleaning milking machines on the eight commercially available teatcup liner materials. The sample liners prepared for use in the clean-in-place process were analyzed by ultraviolet spectrophotometer, ion chromatography and liquid chromatography. Among the eight liner materials, the ultraviolet spectra of 3 sample liners were shown to have a similar peak shape after cleaning, but the ultraviolet spectra peak shape of 5 sample liners was noticeably changed. No products were detected by ion chromatography in any of the liner materials used in this study. When the liner materials were only treated with alkaline detergent, some additional peaks were observed using liquid chromatography which indicate the creation of molecular substance and elution from liner materials, however, these peaks disappeared when the liner materials were cleaned with the acid rinse. Therefore, we propose that an acid rinse should be applied, after cleaning the milking machine with the alkaline detergent.

• 한국조리학회지
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• 제22권5호
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• pp.95-105
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• 2016

본 연구는 인디언시금치 열매를 이용한 건강 기능성 젤리 개발을 위해 인디언 시금치 열매 착즙액 20~80%를 첨가하여 젤리를 제조한 다음, 이화학적 및 관능적 특성을 평가하여 새로운 젤리 제품 개발 가능성을 살펴보았다. 당도는 인디언시금치 착즙액 $3.4^{\circ}Brix$로 나타났다. 색도는 첨가량이 증가할수록 명도 L값은 감소하였고, 적색도 a값과 황색도 b값도 첨가량이 증가할수록 감소하는 경향을 보였다. 인디언시금치 열매 착즙액의 DPPH radical 소거활성 측정 결과, 인디언시금치 열매 착즙액은 15.67 mg/mL로 나타났고, 총 폴리페놀 함량은 7.00 mg/g이었다. 인디언시금치 열매 착즙액 첨가량이 증가할수록 DPPH radical 소거활성과 총 폴리페놀 함량이 대조군보다 높게 나타났다. 텍스쳐에서 견고성은 인디언시금치 열매 착즙액 20% 첨가군에서 4.27%로 높은 값을 보였고, 점착성에서는20% 첨가군에서 2.48%로 높게 나타났으며, 80% 첨가군에서 0.91%로 낮게 나타났다. 관능검사 결과 색, 향, 단맛, 씹힘성, 촉촉한 정도, 전체적인 기호도 등에서 인디언시금치 열매 착즙액 40% 첨가군이 가장 높게 평가되었다. 이상의 결과로 인디언시금치 열매 착즙액 첨가 젤리 제조 시 인디언 시금치 열매 착즙액은 40%가 가장 적합하리라 사료되었다.