• Analytical Science and Technology
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• v.34 no.3
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• pp.115-121
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• 2021

Ethyl glucuronide (EtG) and ethyl sulfate (EtS), which are ethanol metabolites, are direct indicators of ethanol intake; they have been studied in a variety of biological samples in forensic science. It is necessary to analyze ethanol metabolites to determine whether the ethanol detected in autopsy cases was due to alcohol consumption before death or due to the ethanol produced from post-mortem decay. In general, EtG and EtS are detected in the blood together with ethanol; however, it may be difficult to secure blood depending on the extent of decay. Therefore, the aforementioned method should be replaced by detecting the ethanol metabolites using tissue biological samples. In this study, we determined the optimal experimental conditions for detecting EtG and EtS from spleen samples using Liquid Chromatography - Tandem Mass Spectrometry (LC-MS/MS). Herein, the test method was validated, and an analysis method was applied to the actual autopsy cases.

• Korean Journal of Agricultural Science
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• v.22 no.2
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• pp.134-142
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• 1995

In order to elevate the efficiency of methane fermentation using the paper mill sludge, this experiment was conducted at two temperature conditions($35^{\circ}C$ and $60^{\circ}C$), and overlooked the addition effects of ethyl acetate as a substrate, nickel as a constituent of $F_430$, and sulfur as a cell growth factor and reductant. The cellulose of paper mill sludge was degraded to lower molecular materials by heating at $60^{\circ}C$ and NaOH treatment. Methane forming rates were 4.8% from NaOH-treated paper mill sludge added with ethyl acetate, 16.5% with sodium sulfide, 19.8% with nickel trioxide, 31.9% with mixture, and 9.6% with control at $60^{\circ}C$, but 0.21% with ethyl acetate, 2.14% with nickel acetate, 3.02% with nickel sulfate, 3.34% with nickel trioxide and 0.62% with control at $35^{\circ}C$. Therefore, methane yield was increased by approximately 10-fold at $60^{\circ}C$ than $35^{\circ}C$, and fermentation liquid added with mixture(nickel trioxide+ethyl acetate+sodium sulfide) at $60^{\circ}C$ showed the medium pH(7.0), higher COD value and lower nitrogen content.

• Journal of the Korean Applied Science and Technology
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• v.26 no.1
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• pp.93-101
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• 2009

Antistatic acrylic resin is made from n-butyl methacrylate, methyl methacrylate, dimethyl amino ethyl methacrylate(DMAEMA), 2-ethyl hexyl methacrylate, hydroxy ethyl methacrylate, 2,2'-azobis iso-butyronitrile by synthesis. To achieve a lowest surface resistance of antistatic acrylic resin was applied to a variety of synthesis processes. The acrylic resin has been determined from the value of surface resistance and -then the antistatic acrylic resin including dimethyl amino ethyl methacrylate of the 10%, 20% and 30% is synthesized. Finally, dimethyl sulfate(DMS) on a variety of weight ratios is added to antistatic acrylic resin. When DMAEMA / DMS weight ratio is 1/1, antistatic acrylic resin isn't haze the lower the surface resistance. Compared to the traditional antistatic agent, all aspects of the physical properties is outstanding.

• Journal of the Korean Society of Food Science and Nutrition
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• v.28 no.3
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• pp.542-546
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• 1999

Uncoated, ethyl cellulose(EC) coated or methacrylic acid copolymer(MAC) coated ferrous sulfate was added to the yoghurt made from whole milk powder and quality changes of those yoghurt were observed. Among treatments uncoated ferrous sulfate added yoghurt showed the lowest quality in the view of pH, total acidity, total counts of lactic acid bacteria, and sensory characteristics. Quality change of MAC comparing to control was lower than that of EC. MAC and EC showed higher TBA value than no iron added or uncoated iron added one during storage. From sensory evaluation, MAC was not signif icantly different from control in color and off flavor after one day storage(p>0.05), however significant difference was observed in off flavor after 7 day storage(p<0.05). From above results, MAC coated ferrous sulfate added yoghurt showed better quality than uncoated or EC coated ferrous sulfate added one during storage.

• Korean Journal of Environmental Agriculture
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• v.21 no.2
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• pp.90-95
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• 2002

A study was carried out to optimize the cleanup step using a solid-phase extraction (SPE) cartridge, $SupelClean^{TM}$ Florisil, for multiresidue analysis of 16 pesticides in cucumber matrix. Eluting efficiencies of two solvent systems including acetone/n-hexane and ethyl acetate/n-hexane mixtures were critically evaluated by recoveries of target anaytes from the SPE Florisil column. Based on the recovery as a measure of eluting efficiency, an acetone/n-hexane (20/80,v/v) mixture provided more than 80% recovery for 15 pesticides except bifenthrin. In case of ethyl acetate/n-hexane, 14 pesticides showed recoveries higher than 75% while those far alachlor and bifenthrin were less than 30%.

• Korean Journal of Microbiology
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• v.30 no.4
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• pp.299-304
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• 1992

An intracellular protease form cells of Pseudomonas carboxydovorans DSM 1227 grown on carbon monoxide was purified 57-fold in six steps to homogeneity with a yield of 4.3% using azocoll as a substrate. The molecular weight of the enzyme was determined to be 150,000. Sodium dodecyl sulfate-gel electrophoresis revealed the purified enzyme to be a dimer with two identical subunits of molecular weight 72,000. The enzyme was stimulated by $Mg^{2+}$ but was inhibited completely by $Cd^{2+}$ $Fe^{2+}$ $Hg^{2+}$, and $^Zn{2+}$ The enzyme activity was also inhibited by EDTA, EGTA, phenylmethylsulfonyl fluoride, and phenyl glyoxal, but was increased by 1-ethyl-3(dimethyl aminopropyl fluoride, and phenyl glyoxal, but was increased by 1-ethyl-3(dimethyl aminopropyl)carbodiimide, iodoacetamide and dithiothereitol. The optimal pH and temperature for the enzyme reaction were found to be 7-8 and 50.deg.C, respectively. Casein and bovine serum albumin were hydrolyzed by the enzyme, but carbon monoxide dehydrogenase was not.

• Bulletin of the Korean Chemical Society
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• v.30 no.1
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• pp.53-56
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• 2009

At room-temperature, a facile, seedless, and environmentally benign green route for the synthesis of star like PbS nanoclusters at 7 min in aqueous solution of 1-ethyl-3-methylimidazolium ethyl sulfate, [EMIM] [$EtSO_{4}$], room-temperature ionic liquid (RTIL), via ultrasonic irradiation is proposed. The X-ray diffraction studies display that the products are excellently crystallized in the form of cubic structure. An energy dispersive X-ray spectroscopy (EDX) investigation reveals the products are extremely pure. The absorption spectra of the product exhibit band gap energy of about 4.27 eV which shows an enormous blue shift of 3.86 eV that can be attributed to very small size of PbS nanoparticles produced and quantum confinement effect. A possible formation mechanism of the PbS nanoparticles using ultrasonic irradiation in aqueous solution of the RTIL is presented.

• Journal of the Korean Chemical Society
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• v.54 no.5
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• pp.567-572
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• 2010

5,10-Methenyltetrahydrofolate synthetase from chicken liver was purified through 30-70% ammonium sulfate fractionation, Q Sepharose Fast Flow anion exchange and Source 15Phe hydrophobic interaction chromatography. Specific activities of cell extract, ammonium sulfate, Q Sepharose Fast Flow and Source 15Phe were 0.0085, 0.031, 0.80 and 1.27 U/mg, respectively. Purification fold activities of cell extract, ammonium sulfate, Q Sepharose Fast Flow and Source 15Phe were 1, 3.7, 94.1 and 149.4, respectively. HPLC gel permeation chromatography and SDS-polyacrylamide electrophoresis experiments indicated that the enzyme is a monomeric protein with a molecular weight of 22.8 kDa. Km for 5-methyl THF and Mg-ATP were $7.1\;{\mu}M$ and $63\;{\mu}M$, respectively. Optimum temperature and pH were $30^{\circ}C$ and 6.0, respectively. The data for metal ion specificity and stoichiometry showed that the maximum activity was obtained with a 1:l. ratio of $Mg^{2+}$. The ATP and Km values increased in the order of MgATP, MgCTP, MgUTP and MgGTP, and the maximum activities also decreased in the same order, indicating MgATP as the most efficient substrate. The enzyme was chemically modified only by tetranitrometane and 1-ethyl-3-(3-dimethyl aminopropyl)-carbodiimide, indicating that tyrosine and carboxylate are present in the active site.

• YAKHAK HOEJI
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• v.29 no.5
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• pp.260-267
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• 1985

A gas chromatography with flame ionization detection was developed to measure tranylcypromine in rat urine. The method involves extraction of the drug and the internal standard, phenylpropylamine from the urine using ethyl acetate and back extraction into 0.5N $H_{2}SO_{4}$. Following final extraction using dichloromethane, both the drug and the internal standard were converted to trifluoroacetyl derivatives and analyzed using a column of 3% SE-30 on 80/100 mesh Chromosorb W(HP). A calibration curve was constructed in the range of $5~50{\mu}g$tranylcypromine sulfate in 0.5ml urine and found to be linear. The detection limit was $2{\mu}g$. The tranylcypromine could be analyzed with the percent recovery of $100.81{\pm}8.13$ (SD) ina concentration range of $8-40{\mu}g$ in 0.5ml urine. When 0.4mmol/kg dose of the drug was administered through, an oral route, excretion percent of tranylcypromine in rat urine over 36hr was found to be $11.90{\pm}6.04$ (SD) for tranyleypromine sulfate and $2.23{\pm}0.63$ (SD) for benzyl trans-2-phenylcyclopropanecarbamate.

• Proceedings of the PSK Conference
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• 2003.10b
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• pp.147.2-147.2
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• 2003

A fast and matrix-assisted laser desorption/ionization-mass spectrometry compatible protein staining method in one- and two-dimensional sodium dodecyl sulfate-polyacrylamide gel electrophoresis is described. It is based on the counterion dye staining method that employs oppositely charged two dyes, Zincon and Ethyl Violet to form an ion-pair complex. It is safe to use since the methanol used previously in staining solution was replaced with ethanol, which is not toxic. The protocol including fixing, staining and quick washing steps can be completed in 1 to 1.5 h depending upon gel thickness. (omitted)