• Journal of the Korean Society of Tobacco Science
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• v.13 no.2
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• pp.20-26
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• 1991

This study was carried out to develop the method of alkaloids analysis and investigate the kinds and contents of alkaloids in flue-cured, burley and oriental tobacco leaves using developed analytical method. The developed analytical method of alkaloids was as followed : Tobacco sample was treated with acid(pH 2∼3) and extracted with chloroform to remove chemical components except alkaloids. Sample solution was treated with alkali(pH 12∼ 13) and was extracted with chloroform to obtain alkaloids from sample solution. After extraction of alkaloids from tobacco leaves, alkaloids were separated and identified by GC, GC/MS using SE-54 fused silica capillary column. Nicotine, nornicotine, myosmine, 9-nicotyline, anabasine, anatabine, 2, 3-bipyridyl, cotinine, formyl nornicotine, acetyl nornicotine and formal anatabine were isolated and identified from the extracts of tobacco leaves. The contents of alkaloids were burley > flue-cured > oriental tobacco leaves, but oriental tobacco leaves were higher nornicotine, cotinine, formyl nornicotine and acetyl nornicotine contents than those of flue-cured tobacco leaves. The burley tobacco harvested in Korea was higher nornicotine contents by 2-6 times in the portions of cutter, leaf and tips position than that of burley tobacco(B3F) harvested in V. S. A.

• Journal of Korean Society for Atmospheric Environment
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• v.20 no.2
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• pp.195-204
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• 2004

In this study, the concentrations of major reduced sulfur compounds (H$_2$S, $CH_3$SH, DMS, and DMDS) were determined from ambient air in a monitoring station located in the mid-eastern area of Seoul. Measurements of sulfur species were conducted by the combination of on -line air sampling, thermal desorption, and capillary GC/PFPD analysis. A total number of 143 hourly samples were collected in the two time periods set between June and July 2003. The mean concentrations of four sulfur species measured in the whole study period were found on the order: DMS (535$\pm$183) > H$_2$S (47$\pm$10) > DMDS (35$\pm$22) > $CH_3$SH (6.19$\pm$29.4 pptv). The results of this study show that the concentrations of DMS at the study area are generally higher than those reported previously in the oceanic environments, while those of other sulfur species are not easy to compare with due to the lack of data. The H$_2$S concentrations were generally higher during the daytime than the nighttime, whereas those of others generally exhibited a reversed diurnal pattern. The overall results of our study suggest that the distribution of major reduced S compounds should be controlled by diverse processes in the urban area.

• Applied Biological Chemistry
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• v.36 no.6
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• pp.424-427
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• 1993

The chloroform extract of mustard leaves (Brassica juncea Cosson) reduced mutagenicity of $AFB_1$ in bacterial assay (Salmonella typhimurium TA100). 4-Decanol was one of major compounds in the chloroform extract when analyzed by GC-MS on HP-5 capillary column. The authentic compound of 4-decanol dissolved in DMSO (0.5%) inhibited mutagenic activities of $AFB_1$ and MNNG in Salmonella typhimurium TA100 at a rate of 99% and 93%, respectively. This result indicates that 4-decanol is an antimutagenic compound present in chloroform extract of mustard leaves.

• YAKHAK HOEJI
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• v.38 no.4
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• pp.389-393
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• 1994

Eight aromatic acids in Panax ginseng were determined by GC. Ultra-1 $(25\;m{\times}0.2\;mm{\times}0.33\;{\mu}M)$ capillary column was employed with temperature programming from $150^{\circ}C$ to $240^{\circ}C$ at a rate of $3^{\circ}C/min$. The mean contents of eight aromatic acids in 8 white ginseng samples were as follows; salicylic acid: 4.30 ppm, cinnamic acid: 18.2 ppm, vanillic acid: 4.22 ppm, gentisic acid: trace, syringic acid: 6.69 ppm, p-coumaric acid: 13.3 ppm, ferulic acid : 21.9 ppm, caffeic acid: 24.3 ppm, respectively.

• Journal of the Korean Society of Tobacco Science
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• v.14 no.1
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• pp.66-78
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• 1992

The essential oil of Korean valerian root ( Valeriana fauriei roar. dasycarpa Hara) was isolated by simultaneous distillation Sl extraction. The oil content of fresh root was 0.7% (wb) and that of dried root was 2.1 5 (db) and sensory analysis of the oil indicated sweet-balsamic, woody and floral characteristic aroma notes. The oil was fractionated into one hydrocarbon fraction and three oxygenated hydrocarbon fractions by using silica gel column chromatograpy. Each fraction was analyzed by capillary GC and GC-MS. Out of 81 characterized compounds, the major compounds were a-pinene, camphene, $\beta$-pinene, bornyl acetate, borneol , bornyl iso-valerate and sesquiphellandrene and the characteristic floral and woody aroma of neutral fraction of Korean valerian root could be due to be the presence of oxygenated compounds such as borneol, bornyl acetate, bornyl iso-valerate, p-ionone ana $\beta$-ionone epoxide. Comparing the yield of Korean valerian root with those from other origins reported, oil content of Korean valerian root was higher than those of European and Indian origins.

• Journal of the Korean Society of Tobacco Science
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• v.19 no.1
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• pp.57-63
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• 1997

The composition of leaf surface lipid in Flue-cured tobacco and their changes during curing was investigated. The flue-cured variety, Nicotiana tabacum cv. NC 82 was cultivated at Eumsung experiment station in 1996. The samples of riced leaves with different stalk Position(Lugs, Cutter, Leaf and Tips) and different curing stage at half yellowing(24hr), yellowing(48 hr) , color axing(72 hr), midrib drying(96 hr) and cured(120 hr) were collected for analysis of leaf surface lipid. $\alpha$ - and $\beta$ - 4, 8, 13-Duvatriene-1, 3-diol($\alpha$, $\beta$-DVT) were major components in leaf surface lipid extracted with methylene chloride and sugar ester was detected slightly DVT content was increased with ascending stalk position, but increasing trend of total hydrocarbon was not observed. While DVT was decreased throughout curing of tobacco leaves, hydrocarbon content did not show significant change during curing process. Twenty-two duvane compounds were detected by capillary GC in duvane fraction isolated from leaf surface lipid and of which 11 compounds were identified by GC-MS. These compounds were decreased with curing in all stalk position.

• Toxicological Research
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• v.25 no.1
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• pp.41-45
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• 2009

This study was conducted to monitor the level of bifenthrin residues in pear sprayed with 2% bifenthrin wettable powder (WP) at the recommended rate at four different schedules prior to harvest. The target analyte was extracted with acetone, partitioned into dichloromethane, and then purified by florisil chromatographic column. The residue determination was performed on a DB-5 capillary column using GC with electron capture detector (ECD). Linearity of this method was quite good ($r^2$ = 0.9951) in the concentration ranged from 0.2 mg/kg to 10 mg/kg. Recovery test was carried out at two concentration levels, 0.2 mg/kg and 1.0 mg/kg, in three replicates, and their rates were from 82.9% to 107.2%. No quantitative bifenthrin was detected in pear of all kinds of treatments including the treatment sprayed 4 times until 7 days before harvest. This sensitive and selective method can be used to monitor the trace residual amounts of bifenthrin in pear in a quite low concentration level.

• The Korean Journal of Food & Health Convergence
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• v.7 no.6
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• pp.1-8
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• 2021

Premna foetida is a woody plant with short and twisted trunk. P. foetida is a scandent, erect shrub or small tree, thorny on the trunk and large branches. Leaves are opposite or whorled and entire or serrate. Premna foetida is a wild plant locally known as "Daun Sebuas". P. foetida is used for it nutritive and as traditional treatment. The fruit and leaves of P. foetida are prepared for salad. The study aimed at the hydrodistillation and antioxidant activity of leaves, stem-bark and fruits essential oil from Premna foetida Linn, they were analysed by capillary GC and GC-MS. Ninety eight compounds representing 81.68±0.02, 37.31±0.05 and 93.45±0.03 of the isolates of leaves, stem-bark and fruits respectively were identified, the most abundant were α -Duprezianene (77.27±0.03, leaves, α-Gurjunene (36.06±0.05) fruits and Hinesol acetate (77.19±0.03) stem-bark. Components among which sesquiterpenoids dominated. The total volatiles were assayed for antioxidant potentials using 2, 2-diphenyl-1-picrylhydrazyl (DPPH). The total volatiles showed strong activity with IC₅₀ of 11.74±0.82㎍/ml, 9.63±0.34 ㎍/ml and 49.73±1.12 ㎍/ml for leaves fruits and stem-bark respectively.

• The Korean Journal of Pesticide Science
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• v.4 no.1
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• pp.1-10
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• 2000

The purpose of this study is to establish the assessment techniques of hazardous chemicals by the development of analytical method of biological samples. In this study, we have developed an extraction method of nine pesticides used for rice paddy that resulted in high recovery from the spiked human urine by the liquid-liquid extraction with diethyl ether at pH 7.0. Calibration curve obtained from each pesticide standard using by gas chromatography/mass spectrometry/selected ion monitoring has shown good linearity and detection limits were the range of $0.4{\sim}2.0$ ng/mL in urine. As a biological monitoring, urine samples of local farmers exposed directly to nine pesticides in the field were collected and analyzed by GC/MS. Of the tested pesticides, metabolites of phenthoate assumed were identified by GC/MS analysis. No parent compound was detected.

• Journal of Food Hygiene and Safety
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• v.36 no.1
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• pp.34-41
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• 2021

The purpose of this research is to improve analysis methods of determining the contents of fatty acids in infant formulas and follow-up formulas. A gas chromatography (GC) method was performed on a GC system coupled to flame ionization detector, with a fused silica capillary column (SP2560, 100 m×0.25 mm, 0.20 ㎛). The method was validated using standard reference material (SRM, NIST 1849a). Performance parameters for method validation such as specificity, linearity, limits of detection (LOD) and quantification (LOQ), accuracy and precision were examined. The linearity of standard solution with correlation coefficient was higher than 0.999 in the range of 0.1-5 mg/mL. The LOD and LOQ were 0.01-0.06 mg/mL and 0.03-0.2 mg/mL, respectively. The recovery using standard reference material was confirmed and the precision was found to be between 0.8% and 2.9% relative standard deviation (RSD). Optimized methods were applied in sample analysis to verify the reliability. All the tested products had acceptable contents of fatty acids compared with component specification for nutrition labeling. The result of this research will provide efficient experimental information and strengthen the management of nutrients in infant formula and follow-up formula.