• Journal of Microbiology and Biotechnology
• /
• v.10 no.3
• /
• pp.386-393
• /
• 2000

Recent research on the fatty acyl chains in the membrane lipids in Sarcina ventriculi has shown that unusually long chain bifunctional fatty acyl components are the major components of the total lipid. However, these studies did not yield any information on the complete structures of the lipid species containing these fatty acids. In this study, the structures of a new family of glucolipids containing bifunctional acyl chains are described. These structures were determined using NMR(Nuclear Magnetic Resonance) Spectroscopy, GC (Gas Chromatography)/MS (Mass Spectrometry), FTIR (Fourier Transform Infrared) spectroscopy, and FAB (Fast Atom Bombardment) mass spectrometric studies. One of the major bifunctional acyl components of the $\alpha$-glucolipids was an $\omega$-formylmethyl ester indicating the presence of plasmalogen. The general structure of the lipid components was one in which the two head groups were separated by a membrane-spanning acyl species. One head group component is a glycerol moiety of each head group, and the other is a glyceryl clucoside. Two regular chain fatty acids, one on the glycerol moiety of each head group, are also present and meet in the middle of the membrane, roughly equidistant from each head group.

• BMB Reports
• /
• v.29 no.5
• /
• pp.423-428
• /
• 1996

A superoxide anion radical scavenger isolated from Capsella bursa-pastoris was characterized by infrared (IR) spectroscopy, sugar analysis, ultraviolet (UV) spectroscopy, $^{1}H$ and $^{13}C$ nuclear magnetic resonance (NMR) spectroscopies, and fast atom bombardment (FAB) mass analysis. The compound was assumed to be a flavonoid-O-glycoside from IR spectrum and UV absorption maxima. When the sugar composition of the compound was examined by thin layer chromatography (TLC) and gas chromatography (GC) of the acid hydrolysate, only glucose was detected. According to the results of UV spectrotroscopy by using shift reagents, the compound was supposed to be luteolin (5,7,3',4'-tetrahydroxy flavone) or chrysoeriol (5,7,4'-trihydroxy-3'-methoxy flavone) with glucose. Based on $^{1}H$- and $^{13}C-NMR$ spectroscopies, the compound was deduced as 7,4'-dihydroxy-5,3'-dimethoxy-${\alpha}$-6-c-glucosyl-${\beta}$-2"-o-glucosyl flavone. In FAB mass analysis the compound was finally characterized as 7,4'-dihydroxy-5,3'-dimethoxy-${\alpha}$-6-c-glucosyl-${\beta}$-2"-o-glucosyl flavone ($C_{29}H_{34}O_{16}$, M.W.=638).

• Journal of Sensor Science and Technology
• /
• v.13 no.1
• /
• pp.41-46
• /
• 2004

There is currently much interest in the development of instruments that emulate the senses of humans. Increasingly, there is demand for mimicking the human sense of smell, which is a sophisticated chemosensory system. An electronic nose system is applicable to a large area of industries including environmental monitoring. We have designed a protable electronic nose system using an array of commercial chemical gas sensors for recognizing and analyzing the various odours. In this paper, we have implemented a portable electronic nose system using an array of gas sensors for recognizing and analyzing VOCs (Volatile Organic Compounds) in the field. The accuracy of a portable electronic nose system may be lower than an instrument such as GC/MS (Gas Chromatography/Mass Spectrometer). However, a portable electronic nose system could be used on the field and showed fast response to pollutants in the field. Several different algorithms for odours recognition were used such as BP (Back-Propagation) or LM-BP (Levenberq-Marquardt Back-Propagation). We applied RBF (Radial Basis Function) Network for recognition and quantifying of odours, which has simpler and faster compared to the previously used algorithms such as BP and LM-BP.

• Mass Spectrometry Letters
• /
• v.10 no.1
• /
• pp.1-10
• /
• 2019

Amphetamine-type stimulants (ATS) are a group of ${\beta}$-phenethylamine derivatives that produce central nervous system stimulants effects. The representative ATS are methamphetamine and 3, 4-methylenedioxymethamphetamine (MDMA), and abuse of ATS has become a global problem. Methamphetamine is abused in North America and Asia, while amphetamine and 3, 4-methyle nedioxym ethamphetamine (Ecstasy) are abused in Europe and Australia. Methamphetamine is also the most abused drug in Korea. In addition to the conventional ATS, new psychoactive substances (NPS) including phenethylamines and synthetic cathinones, which have similar effects and chemical structure to ATS, continue to spread to the global market since 2009, and more than 739 NPS have been identified. For the analysis of ATS, two tests that have different theoretical principles have to be conducted, and screening tests by immunoassay and confirmatory tests using GC/MS or LC/MS are the global standard methods. As most ATS have a chiral center, enantiomer separation is an important point in forensic analysis, and it can be conducted using chiral derivatization reagents or chiral columns. In order to respond to the growing drug crime, it is necessary to develop a fast and efficient analytical method.

• Journal of the Korean Wood Science and Technology
• /
• v.40 no.3
• /
• pp.204-211
• /
• 2012

In this study, fast pyrolysis of pitch pine (Pinus rigida) was performed in a fluidized bed reactor under the temperature ranges between 400 and $550^{\circ}C$ at the residence time of 1.9 sec. Essential pyrolytic products (bio-oil, biochar, and gas) were produced and their yield was clearly influenced by temperature. The maximum yield of bio-oil was observed to 64.9 wt% (wet basis) at the temperature of $500^{\circ}C$. As pyrolysis temperature increased, the yield of biochar decreased from 36.8 to 11.1 wt%, while gas amount continuously increased from 16.1 to 33.0 wt%. Water content as well as heating value of bio-oils were obviously sensitive to the pyrolysis temperature. The water contents in the bio-oil clearly decreased from 26.1 ($400^{\circ}C$) to 11.9 wt% ($550^{\circ}C$), with increasing the fast pyrolysis temperature, while their higher heating values were increased from 16.6 MJ/kg to 19.3 MJ/kg. According to GC/MS analysis, 22 degradation compounds were identified from the bio-oils and 10 compounds were derived from carbohydrate, 12 compounds were derived from lignin.

• Journal of Life Science
• /
• v.23 no.7
• /
• pp.933-940
• /
• 2013

The aim of this work was to determine the chemical composition of essential oil from aerial partsof Mentha arvensis L. f. piperascens (MAO) and to evaluate the effect of its fragrant chemicals on electroencephalographic (EEG) activity of human brain. The MAO was obtained by supercritical $CO_2$ extraction. The maximum yield was 2.38% at conditions of $70^{\circ}C$ and 200 bar. There were 32 volatile chemicals with 6 alcohols (67.11%), 13 hydrocarbons (17.05%), 9 esters (11.50%), 2 ketones (7.16%), 1 oxide (2.77%), and 1 aldehyde (0.56%). The major components were (Z,Z,Z)-9,12,15-octadecatrien-1-ol (50.06%), 2-hydroxy-4-methoxyacetophenone (7.50%), and 3,4-dihydro-8-hydroxy-3-methyl-1H-2-benzopyran-1-one (6.60%). Results of the EEG study showed that inhalation of MAO significantly changed the EEG power spectrum values of relative gamma, relative fast alpha, and spectral edge frequency 90%. During the inhalation of MAO, the value of relative fast alpha was significantly increased (p<0.05). On the other hand, the values of gamma and the spectral edge frequency 90% were significantly decreased (p<0.05). The present study suggests that fragrant chemicals of essential oil of M. arvensis reduce the level of mental stress and that they could be used in the treatment of psychophysiological disorders.

• Journal of Food Hygiene and Safety
• /
• v.14 no.4
• /
• pp.339-345
• /
• 1999

The present study was performed to investigate photodegradation rate constants and degradation products of dichlorvos and methidathion by the USEPA method. The two pesticides were very stable in sunlight for 16 days from September 2 to 18, 1998 and humic acid had no sensitizing effect on the photolysis of each pesticide in sunlight. The photolysis rate was fast-est for methidathion, followed by dichlorvos in the presence of UV irradiation. Photodegradation rate constant and half-life of dichlorvos were 0.0208 and 33.3 min, respectively. Photodegradation rate constant and half-life of methidathion were 0.6789 and 1.0min, respectively. The two pesticides were degraded completely in the presence of UV irradiation and UV irradiation with TiO$_2$in about 3 hours. Therefore, it is suggested that UV treatment will be effective for the degradation of pesticides in the process of drinking water purification. In case of dichlorvos and methidathion, UV irradiation with TiO$_2$was more effective for degradation than W irradiation. In order to identify photolysis products, the extracts of degradation products were analyzed by GC/ MS. The mass spectrum of photolysis products of dichlorvos was at m/z 153, those of the photolysis of methidathion were at m/z 198 and 214, respectively. Photolysis products of dichlorvos was Ο, Ο-dimethyl phosphate(DMP), those of methidathion were Ο, Ο-dimethyl phosphorothioate(DMTP) and Ο, Ο-dimethyl phosphorodithioate (DMDTP).

• Microbiology and Biotechnology Letters
• /
• v.35 no.4
• /
• pp.325-333
• /
• 2007

One bacterium with high proteinase production and spore-forming ability was isolated from korean traditional soybean paste(doenjang). The isolated strain was identified as Bacillus subtilis, based on gram-staining, biochemical properties and l6S rRNA gene sequencing, and designated as B. subtilis DJI. Its growth rate was very fast, and it reached its stationary phase within 9 h, and then started to form spores. Bacterial-koji and doenjang were prepared using B. subtilis DJI. Chemical components of the doenjang were determined after 2 months of aging period: amino nitrogen 507 mg%, crude protein 14.3%, crude fat 4.8% and water 54.9%. The composition of total and free amino acids and their ratios of doenjang were changed during the aging period. Among total amino acids in DJI doenjang, glutamic acid, aspartic acid, leucine and arginine were the major amino acids. The fibrinolytic activities of DJI doenjang and traditional doenjangs were 909.7 units/ml and $363.3{\sim}618.6\;units/ml$, respectively. Flavor compounds of DJI doenjang and traditional doenjang were extracted by SDE(simultaneous steam distillation and extraction), and analyzed by GC/MS; DJI doenjang possessed the typically favorable flavor compounds in traditional korean doenjang, with reduced off-flavor compounds.

• Korean Journal of Environmental Agriculture
• /
• v.34 no.4
• /
• pp.294-302
• /
• 2015

BACKGROUND: Chemical accidents have increased owing to chemical usage, human error and technical failures during the last decades. Many countries have organized supervisory authorities in charge of enforcing related rules and regulations to prevent chemical accidents. A very important part in chemical accidents has been coping with comprehensive first aid tool. Therefore, the present research has provided information with the initial applications concern to the rapid analysis of hazardous material using instruments in vehicle of field mode after chemical accidents. METHODS AND RESULTS: Mobile measurement vehicle was manufactured to obtain information regarding field assessments of chemical accidents. This vehicle was equipped with four instruments including gas chromatography with mass spectrometry (GC/MS), Fourier Transform Infrared Spectroscopy (FT-IR), Ion Chromatography (IC), and UV/Vis spectrometer (UV) to analyses of accident preparedness substances, volatile compounds, and organic gases. Moreover, this work was the first examined the evaluation of applicability for analysis instruments using 20 chemicals in various accident preparedness substances (GC/MS; 6 chemicals, FT-IR; 2 chemicals, IC; 11 chemicals, and UV; 1 chemical) and their calibration curves were obtained with high linearity ( r ² > 0.991). Our results were observed the advantage of the high chromatographic peak capacity, fast analysis, and good sensitivity as well as resolution. CONCLUSION: When chemical accidents are occurred, the posted measurement vehicle may be utilized as tool an effective for qualitative and quantitative information in the scene of an accident owing to the rapid analysis of hazardous material.

• The Korean Journal of Mycology
• /
• v.39 no.3
• /
• pp.239-242
• /
• 2011

Eritadenine, a potent compound of hypocholesterolemic activity, was investigated in relation to its content in domestic cultivars and wild types of shiitake (Lentinula edodes). Eighteens strains of shiitake were tested for the quantification of eritadenine by LC-MS/MS analysis. Among the strains, wild type-40 was highest as the content was 3.912 mg/g. Also, Soohyangko was 3.352mg/g, Sanlim No. 9 3.008mg/g, Chunbaegko 2.832 mg/g, Gaeulhyang and KFRI 675 both 2.792 mg/g as high-content strains. Soohyangko and Chunbaegko are applied strains for registration in 2010. Soohyangko is high-temperature type with concentrated fruiting, and 90% of production occurs in the first year, thus, recovery of cost is very fast. Chunbaegko is mid-temperature type with concentrated flushing, and produces "hwago", the best quality, in spring. Wild type-40 is excellent in productivity and is prepared for registration. Wild type-40 could be used as parent strain to make new strain with high eritadenine content.