• Bulletin of the Korean Chemical Society
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• v.25 no.1
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• pp.109-114
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• 2004

A sensitive method for quantitation of glimepiride in human plasma has been established using liquid chromatography-electrospray ionization tandem mass spectrometry (LC-ESI/MS/MS). Glipizide was used as an internal standard. Glimepiride and internal standard in plasma sample was extracted using diethyl etherethyl acetate (1 : 1). A centrifuged upper layer was then evaporated and reconstituted with the mobile phase of acetonitrile-5 mM ammonium acetate (60:40, pH 3.0). The reconstituted samples were injected into a $C_{18}$ reversed-phase column. Using MS/MS in the multiple reaction monitoring (MRM) mode, glimepiride and glipizide were detected without severe interference from human plasma matrix. Glimepiride produced a protonated precursor ion ([M+H]$^+$) at m/z 491 and a corresponding product ion at m/z 352. And the internal standard produced a protonated precursor ion ([M+H]]$^+$) at m/z 446 and a corresponding product ion at m/z 321. Detection of glimepiride in human plasma by the LC-ESI/MS/MS method was accurate and precise with a quantitation limit of 0.1 ng/mL. The validation, reproducibility, stability, and recovery of the method were evaluated. The method has been successfully applied to pharmacokinetic studies of glimepiride in human plasma.

• Journal of Korean Society of Water and Wastewater
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• v.18 no.5
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• pp.638-648
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• 2004

In many drinking water treatment plants, chlorination process is one of the main techniques used for the disinfection of water. This disinfecting treatment leads to the formation of haloacetic acid (HAAs). In this study, headspace solid-phase microextraction (HS-SPME) was studied as a possible alternative to liquid-liquid extraction for the analysis of HAAs in drinking water. The method involves direct derivatization of the acids to their methyl esters without methyl tert-butyl ether (MTBE) extraction, followed by HS-SPME with a $2cm-50/30{\mu}m$ divinylbenzene/carboxen/polydimethylsiloxane fiber. The effects of experimental parameters such as selection of SPME fiber, the volume of sulphuric acid and methanol, derivatization temperature and time, the addition of salts, extraction temperature and time, and desorption time on the analysis were investigated. Analytical parameters such as linearity, repeatability and limit of detection were also evaluated. The $2cm-50/30{\mu}m$-divinylbenzene/carboxen/polydimethylsiloxane fiber, sulphuric acid of 1ml, methanol of 3ml, derivatization temperature of $50^{\circ}C$ derivatization time of 2hrs, sodium chloride salt of 10g, extraction time of 30 minutes, extraction temperature of $20^{\circ}C$ and desorption time of 1 minute at $260^{\circ}C$ were selected as the optimal experimental conditions for the analysis of HAAs. The linearities ($r^2$), relative standard deviations (%RSD) and limits of detection (LOD) for HAAs were 0.9978~0.9991, 1.1~9.8% and $0.05{\sim}0.2{\mu}g/l$, respectively.

• Journal of the Korean Chemical Society
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• v.41 no.9
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• pp.471-482
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• 1997

GC/MS was used to find an optimum experimental condition for the screening of organic acids in urine. Urinary organic acids were isolated through the liquid-liquid extraction method (LLE) to examine the influence of pH and the effect of including the back extraction and oximation processes respectively on the extraction. When pH was adjusted to 0.5 during the extraction without oximation process, relatively higher recovery rate and the smallest relative standard deviations (0.3-12.4%) were obtained. By removing the interference, the addition of back extraction made possible surer identification of organic acids with retention time of 15-16 minutes. Under this condition, we obtained the content distribution of urinary organic acids in healthy Korean children (n=16) by establishing the calibration curves for 51 standard organic acids.

• Journal of Radiopharmaceuticals and Molecular Probes
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• v.2 no.2
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• pp.84-95
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• 2016

Considerably increasing interest in using the theranostic isotopes/ isotope pairs of radiometals like $^{44/47}Sc$ and $^{64/67}Cu$ for diagnosis and/or therapeutic applications in the nuclear medicine procedures necessitates its reliable production and supply. Separation and purification of no-carrier-added (NCA) isotopes from macro quantitates of the irradiated target matrix along with other impurities is a cardinal procedure amongst several other steps involved in its production. Multitudinous methods including but not limited to liquid-liquid (solvent) extraction, extraction chromatography (EXC), ion exchange, electrodeposition and sublimation are routinely applied either solitarily or in combination for the separation and purification of radioisotopes depending on their production routes, radioisotope of interest and impurities involved. However, application of EXC though has shown promises towards the numerous separation techniques have not received much attention as far as its application prospects in the field of nuclear medicine are concerned. Advances in the recent past for application of the EXC resins in separation and purification of the several medically important radioisotopes at ultra-high purity have shown promising behavior with respect to their operation simplicity, acidic and radiolytic stability, separation efficiencies and speedy procedures with the enhanced and excellent extraction abilities. In this mini review we will be talking about the recent developments in the application and the use of EXC techniques for the separation and purification of $^{44/47}Sc$ and $^{64/67}Cu$ for medical applications. Furthermore, we will also discuss the scientific and practical aspects of EXC in the view of separation of the NCA trace amount of radionuclides.

• Analytical Science and Technology
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• v.13 no.5
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• pp.636-645
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• 2000

A method is described for the determination of organotins in water samples by GC/MS. Optimized derivatization methods for ethylation and hydrogenation of organotins were surveyed according to various reaction conditions such as time, pH and concentration of reagents. The organotins were extracted with n-hexane in presence of 0.1% tropolone and hydrogenated with sodium borohydride. Extraction recoveries of organotins with hydrogenation were in the range of 61-112%. After ethylation, organotins in water samples were extracted by liquid-liquid extraction (LLE) and solid-phase extraction (SPE). Using LLE, extraction recoveries were in the range of 74-113%. The recoveries ranged from 61-97% in the case of SPE with styrene-divinylbenzene copolymers. Method detection limits of hydrogenated and ethylated organotins ranged from 0.05 to 0.5 ng/ml and from 0.02 to 0.05 ng/ml, respectively.

• Journal of Ginseng Research
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• v.40 no.4
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• pp.415-422
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• 2016

Background: Rare ginsenosides in Panax quinquefolius L. have strong bioactivities. The fact that it is hard to obtain large amounts of rare ginsenosides seriously restricts further research on these compounds. An easy, fast, and efficient method to obtain different kinds of rare ginsenosides simultaneously and to quantify each one precisely is urgently needed. Methods: Microwave-assisted extraction (MAE) was used to extract nine kinds of rare ginsenosides from P. quinquefolius L. In this article, rare ginsenosides [20(S)-Rh1, 20(R)-Rh1, Rg6, F4, Rk3, 20(S)-Rg3, 20(R)-Rg3, Rk1, and Rg5] were identified by high performance liquid chromatography (HPLC)-electrospray ionization-mass spectrometry. The quantity information of rare ginsenosides was analyzed by HPLC-UV at 203 nm. Results: The optimal conditions for MAE were using water as solvent with the material ratio of 1:40 (w/v) at a temperature of $145^{\circ}C$, and extracting for 15 min under microwave power of 1,600 W. Seven kinds of rare ginsenosides [20(S)-Rh1, 20(R)-Rh1, Rg6, F4, Rk3, Rk1, and Rg5] had high extraction yields, but those of 20(S)-Rg3 and 20(R)-Rg3 were lower. Compared with the conventional method, the extraction yields of the nine rare ginsenosides were significantly increased. Conclusion: The results indicate that rare ginsenosides can be extracted effectively by MAE from P. quinquefolius L. in a short time. Microwave radiation plays an important role in MAE. The probable generation process of rare ginsenosides is also discussed in the article. It will be meaningful for further investigation or application of rare ginsenosides.

• Journal of Korean Medicine Rehabilitation
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• v.30 no.4
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• pp.31-39
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• 2020

Objectives Danggwisoo-san and Jakyakgamcho-tang are frequently prescribed for traffic accident patients in Korea. The aim of this study was to examine index compound analysis, antioxidant activity and amount of starch measurement by extraction method. Methods Danggwisoo-san and Jakyakgamcho-tang were extracted with water and 70% ethanol. Antioxidant activity was measured by 2,2-Diphenyl-1-picrylhydrazyl, 2,2-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) and ferric reducing antioxidant power according to the standard protocol. The contents of the indicator components nodakenin, paeoniflorin, and glycyrrhizin were measured by high-performance liquid chromatography, respectively. All starches were hydrolyzed and then total D-glucose was measured and compared. Results Antioxidant activity was excellent in 70% ethanol in all assays. The index component was jagged because its solubility was different depending on the extraction solvent. Starch content was significantly lower in 70% alcohol extract than water extract. Conclusions The results of this study showed that physiological activities and components are different according to extraction conditions. Each herbal medicine has a suitable extraction solvent. Also, the difference in starch content is an object to be considered as it may affect digestion and absorption.

• Korean Journal of Environmental Agriculture
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• v.36 no.1
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• pp.63-66
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• 2017

BACKGROUND: The phenol concentrations in water samples were determined using gas chromatography after derivatization of the analyte to phenyl acetate followed by extraction using a large volume of solvent. However, this procedure requires an additional purification step and is not analytically efficient. METHODS AND RESULTS: In this study, phenol was first extracted from an acidified water sample using ethyl acetate and then acetylated using acetic anhydride in the presence of a small amount of water and $K_2CO_3$. The derivative was extracted using 1mL of n-butyl acetate. One microliter of the extract was analyzed by GC-MS without further purification. The calibration curve showed good linearity with the $r^2$ value of 0.9968. The method detection limit and the limit of quantitation were estimated to be $0.18{\mu}g/L$ and $0.56{\mu}g/L$, respectively. Repeatability (RSD, n=3) and recovery (n=3) were 9.1%-4.3% and 90.6%-110.5%, respectively. The concentrations of phenol in a few samples of stream water were distributed in the range of $2.51-7.51{\mu}g/L$. CONCLUSION: This method is simpler and faster to implement than those currently utilized and shows high analytical reliability. It can be applied to the quantitative determination of phenol concentrations in surface water and groundwater samples.

• Analytical Science and Technology
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• v.23 no.2
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• pp.196-204
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• 2010

In this study, the following concentrations of some PAHs (Polycyclic Aromatic Hydrocarbons) were investigated; [benzo(a)anthracene, chrysene, benzo(b)fluoranthene, benzo(k)fluoranthene, benzo(a)pyrene, dibenzo(a,h)anthracene, benzo(g,h,i)perylene, indeno(1,2,3-c,d)pyrene] in processed foods (n=165) and cooked meats (n=45) and established the analytical method by characteristics of processed foods. The methodology involved extraction (alkali digestion, liquid-liquid extraction, microwave extraction), clean-up on Sep-Pak Florisil Cartridges and determination by HPLC/FLD (High Performance Liquid Chromatography/Fluorescence Detector). The recovery of overall method for 8 PAHs spiked into these products ranged from 92 to 103%. The mean level of detected foods was found to be benzo(b)fluoranthene $0.9\;{\mu}g/kg$ in smoked salmon, benzo(b)fluoranthene $1.0\;{\mu}g/kg$, benzo(k)fluoranthene $0.3\;{\mu}g/kg$, benzo(a)pyrene $0.9\;{\mu}g/kg$ in dried banana, benzo(b)fluoranthene $0.2\;{\mu}g/kg$, benzo(k)fluoranthene $0.1\;{\mu}g/kg$, benzo(a)pyrene $0.2\;{\mu}g/kg$ in smoked chicken, benzo(b)fluoranthene $1.3\;{\mu}g/kg$, benzo(k)fluoranthene $0.3\;{\mu}g/kg$, benzo(a)pyrene $0.9\;{\mu}g/kg$ in charcoal grilled pork, respectively.

• Journal of the Korea Organic Resources Recycling Association
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• v.17 no.3
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• pp.40-47
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• 2009

Coinjection of alcohol and air or alcohol flooding only were evaluated with 3-D soil tank for removal of nonaqueous phase liquid (NAPL) contaminant from soil. 70%-ethanol and 40%-isopropanol were used for non-NAPL-swelling alcohol and NAPL-swelling alcohol, respectively. 729 ml-benzene was placed in the 37 liter soil tank. Alcohols were respectively injected from the injection well placed near the bottom of the tank and mobilized free phase NAPL and aqueous phases were then recovered from the extraction well placed in the upper part of the soil tank. Approximately 50% of removed NAPLs were free-phase in all experiments. The results were completely different to the previous soil column experiment results and also implied that alcohol properties did not affect the NAPL removal efficiency in the 3-D soil tank experiment. Air was also co-injected with alcohol to evaluate co-injection effects on NAPL removal. Enhanced NAPL removal effect of co-injection of 70%-ethanol and air was also found even in the 3-D soil tank evaluation. However, co-injection effect of 40%-iso-propanol and air was less apparent. This study determined that the most important parameter governing alcohol flooding for NAPL removal would be extraction capacity to recover NAPL and aqueous phase flowing in the soil. More researches are required for improving recovery efficiency of extraction well in real soil contamination conditions.