• Mass Spectrometry Letters
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• 제5권4호
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• pp.104-109
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• 2014

Nonmedical use of prescription stimulants such as methylphenidate (MPH) and amphetamine (AP) by normal persons has been increased to improve cognitive functions. Due to high potential for their abuse, reliable analytical methods were required to detect these prescription stimulants in biological samples. A direct injection liquid chromatography-tandem mass spectrometric (LC-MS/MS) method was developed and implemented for simultaneous determination of MPH, AP and their metabolites ritalinic acid (RA) and 4-hydroxyamphetamine (HAP) in human urine. Urine sample was centrifuged and the upper layer ($100{\mu}L$) was mixed with $800{\mu}L$ of distilled water and $100{\mu}L$ of internal standards ($0.2{\mu}g/mL$ in methanol). The mixture was then directly injected into the LC-MS/MS system. The mobile phase was composed of 0.2% formic acid in distilled water (A) and acetonitrile (B). Chromatographic separation was performed by using a Capcell Pak MG-II C18 ($150mm{\times}2.0mm$ i.d., $5{\mu}m$, Shiseido) column and all analytes were eluted within 5 min. Linear least-squares regression with a 1/x weighting factor was used to generate a calibration curve and the assay was linear from 20 to 1500 ng/mL (HAP), 40-3000 ng/mL (AP and RA) and 2-150 ng/mL (MPH). The intra- and inter-day precisions were within 16.4%. The intra- and inter-day accuracies ranged from -15.6% to 10.8%. The limits of detection for all the analytes were less than 4.7 ng/mL. The suitability of the method was examined by analyzing urine samples from drug abusers.

• Nuclear Engineering and Technology
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• 제7권3호
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• pp.213-222
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• 1975

알카리로 처리한 국산 blown asphalt를 사용해서 방사성 폐액을 180-20$0^{\circ}C$ 범위 내에서 고화처리한 것이 산처리 한것보다 좋은 결과를 얻었으며, 방사선 조사선량이 4.0$\times$$10^{7}$ rad까지도 안정된 고화체로 존재하고 있다. 한편 40wt%의 고형분이 함유되어 있는 $^{137}$Cs-asphalt 고화체의 증류수에 의한 $^{137}$Cs의 용출율이 8.27$\times$$10^{-4}$ g/$\textrm{cm}^2$-day 인데 반하여 $^{90}$ Sr은 낮았으며, 일반적으로 증류수보다 해수때가 또한 pH가 증가함에 따라 용출율은 낮아진다.

• 한국작물학회:학술대회논문집
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• 한국작물학회 2017년도 9th Asian Crop Science Association conference
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• pp.212-212
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• 2017

This experiments were conducted to evaluate the influence of Chlorella culture solution on seed germination of perennial ryegrass seeds. Chlorella are known to contain different bioactive compounds. In present research work, Chlorella culture solution using liquid manure as medium have been used to study their effects on germination and root length. The study conducted a germination experiment in petri-dishes. Four treatments were compared: non-treated control treated with distilled water, Chlorella culture solution and Chlorella culture filtrate, and liquid manure. The germination percentage of perennial ryegrass seeds was highest in the Chlorella culture solution treatment. Days required for 50, 70% seed germination was the fast in Chlorella culture solution and the Chlorella culture filtrate treatment. Root length of perennial ryegrass seeds was long by 1~2cm in the Chlorella culture solution compared with no treated control. The germination index of perennial ryegrass seeds was high by 180~202% in the Chlorella culture solution treatment compared to no treatment. Chlorella culture solution and the Chlorella culture filtrate have shown stimulatory effects in germination and development of root. Use of Chlorella culture solution and the Chlorella culture filtrate can be recommended to farmers as a ecofriendly practice for better germination and growth. Present research work reveals that Chlorella contain certain growth promoting substances which enhances seed germination.

• 분석과학
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• 제36권1호
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• pp.53-58
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• 2023

2'-Hydroxy-3',4'-methylenedioxy-3,4,5-trimethoxychalcone (HMTC) is a newly synthesized chalcone that affects proliferation, cytotoxic potential and apoptosis in human leukemia cells. However, no validated determination method has been described so far for HMTC in biological samples. Thus, we developed a liquid chromatographic method using a tandem mass spectrometry to determine HMTC in rat plasma. Liquid-liquid extraction with ethyl acetate was used for the clean-up procedure. The analyte was separated on a reversedphase column with mobile phase of distilled water and acetonitrile (2:8, v/v, including 0.1 % formic acid). The ion transition of the precursor to the product ion was principally deprotonated ions [M-H]^- at m/z 356.8 → 327.2 for HMTC. This analytical method was successfully applied in pharmacokinetic study of HMTC after intravenous administration in rats.

• 농업과학연구
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• 제47권1호
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• pp.11-18
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• 2020

Eggs are likely to be used in agriculture because they can provide enough nutrients for crop growth. Statistics show that a large number of eggs are lost due to breakage before reaching the final consumer. The purpose of this study was to make a natural liquid fertilizer as a substitute for chemical fertilizers using broken eggs as a resource and to evaluate the efficiency of the formulated fertilizer. To make the liquid fertilizer, the broken eggs and distilled water were mixed at ratios of 6 : 4 and 4 : 6. Then, effective micro-organisms (EM) and sugar were added, and the mixture was fermented. The temperature and electrical conductivity (EC) increased gradually with the fermentation while the pH decreased. When evaluated following the seed germination index method of the compost, it was found that the fertilizer matured 10 days after the beginning of the experiment. The growth experiment was conducted with lettuce in which the fermented liquid fertilizer was compared with a commercial liquid fertilizer. The 6 : 4 treatment produced plants with the densest fresh shoot and roots weighing 41.6 and 4.6 g, respectively. The number of leaves (12.3 per plant) was also the highest for the 6 : 4 treatment. Soil analysis showed that the soil pH was improved, and the soil organic matter was increased in the fermented liquid fertilizer treatment.

• 한국세라믹학회지
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• 제51권2호
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• pp.121-126
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• 2014

The influence of a liquid medium duringa wet-milling process in the grinding and oxidation of silicon powder was investigated. Distilled water, dehydrated ethanol and diethylene glycol were used as the liquid media. The applied grinding times were 0.5, 3, and 12 h. Ground silicon powder samples were characterized by means of aparticle size analysis, scanning electron microscopy(SEM), x-ray powder diffraction (XRD), FT-IR spectroscopy and by a chemical composition analysis. From the results of the characterization process, we found that diethylene glycol is the most efficient liquid medium when silicon powder is ground using a wet-milling process. The FT-IR results show that the Si-O band intensity in an unground silicon powder is quite strongbecause oxygen becomes incorporated with silicon to form $SiO_2$ in air. By applying deionized water as a liquid medium for the grinding of silicon, the $SiO_2$ content increased from 4.12% to 31.7%. However, in the cases of dehydrated ethanol and diethylene glycol, it was found that the $SiO_2$ contents after grinding only changed insignificantly, from 4.12% to 5.91% and 5.28%, respectively.

• Bulletin of the Korean Chemical Society
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• 제31권5호
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• pp.1192-1198
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• 2010

Pharmaceuticals and personal care products (PPCPs) are emerging contaminants in the aquatic environment. Many pharmaceuticals are not completely removed during wastewater treatment, leading to their presence in wastewater treatment effluents, rivers, lakes, and ground water. Here, we developed analytical methods for monitoring ten pharmaceuticals from surface water by LC/ESI-MS/MS. For sample clean-up and extraction, MCX (mixed cation exchange) and HLB (hydrophilic-lipophilic balance) solid-phase extraction (SPE) cartridges were used. The limits of detection (LOD) in distilled water and the blank surface water were in the range of 0.006 - 0.65 and 1.66 - 45.05 pg/mL, respectively. The limits of quantitation (LOQ) for the distilled water and the blank surface water were in the range of 0.02 - 2.17 and 5.52 - 150.15 pg/mL, respectively. The absolute recoveries for fortified water samples were between 62.1% and 125.4%. Intra-day precision and accuracy for the blank surface water were 2.9% - 24.1% (R.S.D.) and -16.3% - 16.3% (bias), respectively. In surface wastewater near rivers, chlortetracycline and acetylsalicylic acid were detected frequently in the range of 0.017 - 5.404 and 0.029 - 0.269 ng/mL, respectively. Surface water near rivers had higher levels than surface water of domestic treatment plants.

• 한국전기전자재료학회논문지
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• 제25권10호
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• pp.824-829
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• 2012

Zn wires have been electrically exploded in methanol or distilled water using the pulsed power technologies. The nanopowders produced by the explosions have been observed by using SEM and TEM, and analyzed its phase by using EDS and XRD. The nanopowders produced in distilled water showed ZnO phase only. On the other hands, the nanopowder produced in methanol showed mixed phases with Zn and ZnO. The HR-TEM images of the nanopowders produced in methanol showed that the some particles have been coated with carbon like materials. It is considered that the carbon coatings could be depended on the positions of the particles during the plasma state formed by explosion.

• 생약학회지
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• 제34권3호통권134호
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• pp.201-205
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• 2003

This paper is intended as an investigation of the analysis of high-performance liquid chromatography and the method of extraction of decursin and decursinol angelate in Angelica gigas roots. There are three kinds of extraction methods: distilled water, 50% EtOH and 100% EtOH. The condition of HPLC was obtained on a reversed-phase column $(Polarity\;dC_{18},\;4.6{\times}250 mm,\;5\;{\mu}m)$ using a phosphate buffer-acetonitrile-sodium lauryl sulfate as the mobile phase. Under these chromatographic conditions, UV detector was 230 nm, column temperature $30^{\circ}C$ and the speed of a current 1.0 ml/min, respectively. The results of extraction with distilled water, 50% EtOH and 100% EtOH in Angelica gigas roots were as follows. The concentrations of decursin and decursinol angelate were 182 and 153 ppm (distilled water), 3,142 and 2,547 ppm (50% EtOH) and 3,341 and 2,778 ppm (100% EtOH). There were high positive correlations between the concentrations of decursin and EtOH (r=0.8928, p<0.01) and decursinol angelate and EtOH (r=0.9009, p<0.01).

• 한국식품영양과학회지
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• 제26권4호
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• pp.582-587
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• 1997

AsA 수용액 또는 당근즙액 또는 당근을 첨가한 채소즙들에서 반응시간과 온도에 따른 ascorbic acid(AsA) 와 dehydroascorbic acid(DHAA)의 함량 변화를 HPLC를 이용하여 정 량분석 하였다. 당근즙액에 있는 AsA가 물에 있는 AsA보다 더 안정한 것으로 나타났고, AsA 수용액과 AsA+당근즙액에 있는 AsA의 함량은 반응 시간과 저장온도의 증가에 의해 점차로 감소되는 것으로 나타났다 또한 냉장온도(4$^{\circ}C$)에서 2시간,24시간 보관된 당근즙액과 당근+채소즙액의 AsA 함량도 시간 경과에 따라 점차로 감소함을 알 수 있었다. 당근즙액 또는 당근을 첨가한 채소즙의 AsA, DHAA, 총 비타민 C 함량은 냉장온도에서 2,24시간 보관함에 따라, 모든 시료의 AsA 함량은 시간경과에 따라 점차적으로 파괴되었지만, DHAA 함량은 서서히 증가하는 것으로 나타나 총 비타민 C(AsA+DHAA)의 값은 2시간 저온에서 방치시 90~97%의 높은 비타민 C의 잔존율을 가졌으며, 24시간 방치 시에도 총 비타민 C 함량에 대한 큰 변화는 없었다. 결국 저온 보관시 당근 첨가에 의한 채소즙액의 총 비타민 C의 손실은 거의 없는 것으로 확인 되었다.