• Korean Journal of Pharmacognosy
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• 제7권4호
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• pp.237-240
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• 1976

To investigate the constituents of following plants, Valeriana fauriei species, which are V. fauriei var. fauriei $H_{ARA}$, V. fauriei form. coreana $H_{ARA}$ and V. fauriei var. dasycarpa $H_{ARA}$, we carried out gas-liquid chromatographical analysis of the volatile oils of these plants and found that camphene, l-bornylacetate, ${\alpha}-pinene,\;{\beta}-pinene$, d,l-limonene, l-borneol and ${\alpha}-kessylacetate$ were common components in their volatile oils. However, their terpenoidal composition was considerably different from ${\alpha}-kessylacetate$ in V. faurie var. fauriei, from kessanol, ledol, kessoglycol and nardol in V. fauriei var. dasycarpa, and from kessoglycoldiacetate, ${\alpha}-kessylalcohol$, faurinone and terpineol in V. faurie form. coreana. It was found by gas-liquid chromatography that the terpenoidal patterns of these Korean valerians were similar to those of Japanish valerians.

• Journal of Korean Society for Atmospheric Environment
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• 제34권1호
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• pp.120-143
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• 2018

The analytical methods and their ambient levels of organic nitrogenous compounds such as nitrosamines, nitramines (nitroamines), imines, amides and nitro-polycyclic aromatic hydrocarbons (nitro-PAHs) in the atmosphere are summarized and discussed. Sampling for the analysis of organic nitrogenous compounds was mostly conducted using high volume air sampler. The direct liquid extraction (DLE) using sonification and the pressurized liquid extraction (PLE) using the accelerated solvent extraction (ASE) have been frequently employed for the extraction of organic nitrogenous compounds in the atmospheric samples. After extraction, clean-up via filtration and the solid phase extraction (SPE) and concentrations using nitrogen and rotary evaporator have been generally conducted but in some studies the clean-up and concentration steps have been omitted to prevent the loss of analyte and improve the recovery rate of the analytical procedure. Instrumental analysis was mainly carried out using gas chromatography (GC) or the high performance liquid chromatography (HPLC) coupled with the single quadrupole mass spectrometer or tandem mass spectrometer in the electron ionization (EI), positive chemical ionization (PCI) and negative chemical ionization (NCI) mode and analysis sensitivity of nitrosamines and nitramines were higher in NCI mode. Desirable sampling and analysis methods for analyzing particulate organic nitrogenous compounds are suggested.

• Korean Journal of Food Science and Technology
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• 제16권1호
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• pp.51-58
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• 1984

Grains of naked barley (Baekdong cultivar) were polished, powdered and subjected to the successive extraction into free and bound liquid fractions. These were further fractionated into lipid classes and quantified by means of thin layer chromatography, column chromatography and gas-liquid chromatography. Contents of free and bound lipids in barley flour were 2.27% and 1.01%, which were decreased to 2.12% and 0.76%, respectively, after purification. Free and bound lipids were consisted of monoglycerides, diglycerides, triglycerides, free sterols, sterol esters, free fatty acids and polar lipids. Major constituents of free lipids were 56.2% triglycerides, 14.9% free fatty acids and 13.4% sterols while those of bound lipids were 73.8% polar lipids, 8.4% free fatty acids and 5.2% triglycerides. The content of non-polar lipids in free lipids was 93.6% as compared with 26.2% in bound lipids. However, phospholipids content in bound lipids was 55.5% as compared with 2.5% in free lipids, and glycolipids content in bound lipids was 19.4% as compared with 3.9% in free lipids. Major fatty acids in the free and bound lipid fractions were linoleic acid 52.1%, 54.8%, palmitic acid 24.8%, 30.0% and oleic acid 15.6%, 8.8%, respectively, showing similar patterns in both fractions. The amount of unsaturated fatty acids in free lipids was 72.8% as compared with 68.0% in bound lipids. In comparing the fatty acid composition of non-polar lipids, glycolipids and phospholipids, no difference was observed between free and bound lipid fractions while a slight difference was found among the lipid constituents.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• 제15권7호
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• pp.563-571
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• 2003

The forty vapor-liquid equilibrium data of the binary system, HFC125＋Propane, were measured between 273.15 and 313.15 K at 10 K interval and the composition range 0.2∼0.75, respectively. Experiments were performed in a circulation type apparatus in which the vapor phase was forced through the liquid phase. The composition at equilibrium were mea-sured by gas chromatography, and its response was calibrated using gravimetrically prepared mixtures. Vapor-liquid equilibrium data were calculated by using CSD equation of state and compared with the experimental data.

• Korean Journal of Environmental Agriculture
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• 제1권1호
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• pp.14-21
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• 1982

Analytical methods for residues of six N-methylcarbamate insecticides were investigated to compare the minimum detectability, recovery from several crops and feasibility of multiple residue analysis. Those methods studied in this work included spectrophotometry by diazotization and gas chromatography by N-trifluoroacetylation(TFA), pentafluorobenzylether(PFB) and dinitrophenylether (DNP) derivatization. Maximum absorbed wavelength of the diazotized MIPC, XMC, BPMC, propoxur and carbofu ran was around 460 ㎚, while that of carbaryl recorded 510 ㎚. Recovery from brown rice and apple by diazotization method ranged from 80 to 120% and minimum detectable limits were 0.03 to 0.05 ppm in 50 g of the sample. Minimum detectability of PFB derivatives by gas chromatography was superior to TFA and DNP derivatives. DNP derivatives showed the longest retention time among the given derivatives. Recovery from crops by gas chromatographic met hod ranged 74 to 94%, 78 to 93%, and 85 to 99% in brown rice, rice straw and apple, respectively. Limit of detection was 0.01 ppm for TFA, 0.005 ppm for PFB and 0.02 ppm for DNP derivatives in 50 g of the crop samples.

• Journal of the Korean Chemical Society
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• 제29권5호
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• pp.503-509
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• 1985

Sixteen organochlorine pesticides extracted out from the crops and cleaned by solvent-solvent partitioning and Florisil column chromatography were determined by gas-liquid chromatography. The majority of the pesticides were well separated by being eluted through 5% QF-1 column and some of them through 3% OV-17 column and 2.596 DC-200/2.5% QF-1 column, and the eluted pesticides were detected by $^{63}Ni$ electron capture detector. The linear calibration curves were obtained for the most of pesticides while some curves were slightly deviated from the linearity. In the determination of 16 pesticides added to thirteen kinds of crops, the recoveries were showed over 85% for the most cases and the relative standard deviations of 5 analyses were less than 12.1%. The results were within the criteria of the AOAC method.

• Microbiology and Biotechnology Letters
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• 제41권3호
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• pp.272-277
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• 2013

In this study, the tar compounds derived from the plant cell cultures of Taxus chinensis were first identified and then quantified via gas chromatography/mass spectrometry (GC/MS) and gas chromatography (GC). 2-Picoline, 2,5-xylenol, acenaphthene, 1-methylnaphthalene and o-xylene were found to be the major tar compounds by biomass. These compounds were identified and confirmed by comparing their retention times with those of authentic compounds. Each compound also spiked with the pure standard. The contents of 2-picoline, 2,5-xylenol, acenaphthene, 1-methylnaphthalene, and o-xylene in biomass were 0.2512, 0.1586, 0.1240, 0.0942 and 0.0525 wt%, respectively. Liquid-liquid extraction and adsorbent treatment were able to remove 42% and 94% of the tars from biomass, respectivly. After hexane precipitation, all of the tars were perfectly removed.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• 제9권1호
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• pp.23-40
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• 1999

The analysis of thiodiglycolic acid in urine has been used as an index of biological exposure to vinyl chloride. Unfortunately thiodiglycolic acid has a strong hydrophilic character, because it has two carboxylic groups, so that it can only be extracted with organic solvent with a great difficulty. Underivatized thiodiglycolic acid tends to tail because of non-specific interaction with the inert support. Therefore, esterification is the obvious first choice for derivatization of thiodiglycolic acid, particularly for gas chromatography. In this study, the focus of interest is to compare two method of esterifications (methylation and silylation). Methylation is to make the methyl ester of thiodiglycolic acid by reaction with diazomethane. Silylation is to make the trimethylsilyl ester of thiodiglycolic acid by reaction with N-trimethylsily-ldiethylamine. The results and conclusions are as the following: 1. The detection limit (sensitivity) of methylated thiodiglycolic acid was $5.00{\mu}g/m{\ell}$ and silylated thiodiglycolic acid was $3.07{\mu}g/m{\ell}$ by gas chromatography with flame ionization detector. 2. The optimal liquid-liquid extraction of thiodiglycolic acid was as following: To each of the tubes, $15m{\ell}$ of urine, concentrated sulfuric acid (pH 1 - 2) and 5 gsodium sulfate were added. The samples was extracted three times with $5m{\ell}$ ethylacetate each time. 3. The methylated thiodiglycolic acid was more stable than silylated thiodiglycolic acid in extractional solvent which contained humidity. 4. The precision (pooled coefficient of variation for 4 days) of the analysis was 0.07324 in methylated thiodiglycolic acid with external standard calibration, and 0.07033 in methylated thiodiglycolic acid with internal standard calibration. 5. The precision (pooled coefficient of variation for 4 days) of the analysis was 0.10914 in silylated thiodiglycolic acid with external standard calibration, and 0.13602 in silylated thiodiglycolic acid with internal standard calibration. From the above results, the analysis of methylated thiodiglycolic acid was more sensitive (limit of detection) than silylated thiodiglycolic acid by gas chromatography. However, the methylated thiodiglycolic acid was stable in the humidity and was separated sharply on chromatogram. Also, analysis of methylated thiodiglycolic acid was more precise (pooled coefficient of variation for 4 days) than silylated thiodiglycolic acid. In conclusion, it is established that the analysis of methylated thiodiglycolic acid is appropriate for biological monitoring of exposure to vinyl chloride.

• Analytical Science and Technology
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• 제7권1호
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• pp.11-15
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• 1994

From the aerial parts of Saururus chinensis growing in Korea, four flavonoids (hyperin, isoquercitrin, quercitrin and rutin) were isolated and identified by high performance liquid chromatography, gas chromatography and thin layer chromatography. However, avicularin, which was known as one of the main constituents of flavonoid, was not detected.

• Journal of Plant Biology
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• 제32권1호
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• pp.41-49
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• 1989

Phenolic compounds such as gallic acid, ferulic acid, p-hydroxybenzoic acid, vanillic acid, salicylic acid, tannic acid, and hydroquinone were identified from the aqueous extracts and volatile substances of tomato plant by paper chromatography, high performance liquid chromatography and gas chromatography. The seed germination and seedling growth of the experimental species, lettuce and egg plant, were severely inhibited in 5$\times$10-3M of phenolic reagents identical to those identified from tomato plant. Germination and growth rate of test species in 5$\times$10-4M and 5$\times$10-5M were higher than that of 5$\times$10-3M. Therefore, 5$\times$10-3M of phenolic compounds would be assumed to be threshold concentration for allelopathic effects.