• Korean Journal of Food Science and Technology
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• v.20 no.1
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• pp.100-105
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• 1988

Composition of organic acids and fatty acids in three edible mushrooms, Pleurotus ostreatus, Lentinus edodes and Agaricus bisporus were analyzed by gas-liquid chromatography and compositional differences of these components depending on species, sizes and portions (pileus and stipe) were investigated. Lactic, oxalic. fumaric. citric and pyroglutamic acid were identified in each of the three mushrooms and the major organic acids were malic, citric and pyroglutamic acid, respectively. The total organic acid contents were in the range of 2.4-4.0% in Pleurotus ostreatus, 1.7-3.6% in Lentinus edodes and 1.9-3.1% in Agaricus bisporus. Especially oxalic and pyroglutamic acid in Pleurotus ostreatus, malic and citric acid in Lentinus edodes and fumaric acid in Agaricus bisporus were higher in pileus than stipe. The total organic acid contents decreased as the size of pileus developed and especially the decrease of citric acid were marked. On the other hand, the major fatty acids in three mushrooms were linoleic, palmitic and oleic acid. But fatty arid compositions were not significantly different depending on species, sizes and portions.

• Journal of the Korean Chemical Society
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• v.36 no.6
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• pp.849-856
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• 1992

We prepared a simple, economic and versatile preparative system for an enantiomeric separation. Hydrophobic amino acid enantiomers were resolved in the preparative scale by a centrifugal liquid chromatography on the N-hexadecyl-L-proline coated reversed phase. The factors controlling the retention and resolution of racemic amino acids such as the concentration of Cu(Ⅱ), pH of the eluent, the type and content of organic modifier, and rpm of CLC were examined. Several mg of hydrophobic amino acid enantiomers were separated preparatively. To separate all of different amino acid enantiomers, various coating material will be investigated.

• Bulletin of the Korean Chemical Society
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• v.25 no.10
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• pp.1508-1512
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• 2004

A gas chromatography/mass spectrometric (GC/MS) method has been developed for the determination of trace mono-n-butyltin (MBT), di-n-butyltin (DBT), and tri-n-butyltin (TBT) compounds in sediments. Samples were extracted by 10% acetic acid in methanol containing 0.03% tropolone and were then derivatized for GC/MS analysis. Ethylation by sodium tetraethylborate and phenylation by sodium tetraphenylborate were evaluated as a derivatization reaction of the organotins in sample extract. n-Hexane was added into reaction media in the beginning of the reaction for the continuous extraction of derivatized organotins. Ethylation requires less than 2 hours to get proper derivatization yields for MBT, DBT, and TBT altogether and produces relatively low amounts of side reaction products. Compared to ethylation, phenylation requires much longer time but provides relatively lower yield and produces considerable amounts of side reaction products. Therefore, the ethylation reaction was applied for the analysis of organotin compounds in sediment. An isotope dilution mass spectrometric (IDMS) method based on GC/MS has been applied to the accurate determination of DBT compounds in the sediments. The IDMS results from the analyses of sediment samples showed a reasonable repeatability and a good agreement with the values obtained by IDMS based on liquid chromatography/induced coupled plasma/mass spectrometry.

• Journal of the Korean Wood Science and Technology
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• v.47 no.4
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• pp.509-518
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• 2019

This study analyzed the effect of organic solvent extractives on the classification of wood species via near-infrared spectroscopy (NIR). In our previous research, five species of Korean softwood were classified into three groups (i.e., Cryptomeria japonica (cedar)/Chamaecyparis obtuse (cypress), Pinus densiflora (red pine)/Pinus koraiensis (Korean pine), and Larix kaempferi (Larch)) using an NIR-based principal component analysis method. Similar tendencies of extractive distribution were observed among the three groups in that study. Therefore, in this study, we qualitatively analyzed extractives extracted by an organic solvent and analyzed the NIR spectra in terms of the extractives' chemical structure and band assignment to determine their effect in more detail. Cedar/cypress showed a similar NIR spectra patterns by removing the extractives at 1695, 1724, and 2291 nm. D-pinitol, which was detected in cedar, contributed to that wavelength. Red pine/Korean pine showed spectra changes at 1616, 1695, 1681, 1705, 1724, 1731, 1765, 1780, and 2300 nm. Diterpenoids and fatty acid, which have a carboxylic group and an aliphatic double bond, contributed to that wavelength. Larch showed a catechin peak in gas chromatography and mass spectroscopy analysis, but it exhibited very small NIR spectra changes. The aromatic bond in larch seemed to have low sensitivity because of the 1st overtone of the O-H bond of the sawdust cellulose. The three groups sorted via NIR spectroscopy in the previous research showed quite different compositions of extractives, in accordance with the NIR band assignment. Thus, organic solvent extractives are expected to affect the classification of wood species using NIR spectroscopy.

• Korean journal of food and cookery science
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• v.19 no.1
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• pp.1-10
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• 2003

All optional ingredient, Jasoja(Perillae semen) was adopted to improve Dongchimi in qualify during fermentation. Free sugar, free amino acid, non-volatile organic acid and volatile compounds were determined during fermentation at 10$^{\circ}C$ for 45 days. Free sugar content was slightly higher in 0.5%-Jasoja-treated samples than that of control. The contents of free amino acids in control Dongchimi (without jasoja) increased slowly during fermentation while those in 0.5 %-treated samples began to decrease after reaching their maximum value on the day 11 when Dongchimi became most acceptable. There were 6 non-volatile organic acids, such as lactic, fumaric, succinic, malic, tartaric, and citric acid. Among these, only lactic and succinic acid increased consistently with fermentation while others decreased. Volatile components in Dongchimi were mostly identified as sulfur-containing compounds by gas chromatography. Their numbers and % peak areas in the gas chromatogram decreased slightly with the increase in organic acids and alcohols during fermentation period. On the other hand, Dongchimi prepared with Jasoja maintained its contents of total acids as well as the level of sulfur-containing compounds.

• Journal of Korean Society for Atmospheric Environment
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• v.31 no.5
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• pp.482-492
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• 2015

Ground-based measurements were conducted from January 6 to 12 of 2015 for understanding characteristics of nitrogen containing carbonaceous aerosols as 16 amino acids at the Mokpo National University, Korea. The detailed amino acid components such as Cystine ($(SCH_2CH(NH_2)CO_2H)_2$) and Methionine ($C_5H_{11}NO_2S$) and their sources were analyzed by High-Performance Liquid Chromatography with Fluorescence Detection (HPLC-FLD) for behavior of secondary products in particulate matter. In addition, organic carbon (OC) and elemental carbon (EC) based on the carbonaceous thermal distribution (CTD), which provides detailed carbon signature characteristics relative to analytical temperature, and water soluble organic carbon (WSOC) by total organic carbon (TOC) analyzer were used to understand the carbon compound behaviors. The backward trajectories were discussed for originations of carbonaceous aerosols as well. Different airmasses were classified with the amino acids and OC thermal signatures. The results can provide to understand the aging process influenced by the long-range transport from East Sea area.

• Macromolecular Research
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• v.17 no.11
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• pp.912-918
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• 2009

An optically active diacid containing the L-histidine moiety was prepared by reacting pyromellitic dianhydride (1,2,4,5-benzenetetracarboxylic acid 1,2,4,5-dianhydride) 1 with L-histidine 2 in acetic acid, and was polymerized with several aromatic diamines 5a-g to obtain a new series of optically active poly(amide-imide)s (PAIs) using two different methods, such as direct polycondensation in a medium consisting of N-methyl-2-pyrrolidone (NMP)/triphenyl phosphite (TPP)/calcium chloride ($CaCl_2$)/pyridine (Py) and direct polycondensation in a tosyl chloride (TsCl)/pyridine (Py)/N,N-dimethylformamide (DMF) system as a condensation agent. The resulting new polymers 6a-g with inherent viscosity was obtained in good yield. The polymers were readily soluble in polar organic solvents, such as N,N-dimethyacetamide (DMAc), N,N-dimethyformamide (DMF), and dimethyl sulfoxide (DMSO). The obtained polymers were characterized by FTIR, specific rotation, elemental analysis as well as $^1$H-NMR spectroscopy and gel permeation chromatography (GPC). The thermal stability of the resulting PAIs was evaluated with thermogravimetric analysis techniques under a nitrogen atmosphere.

• Journal of the Korean Chemical Society
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• v.18 no.5
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• pp.358-362
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• 1974

The anion exchange separation of a number of benzoic acid and its derivatives has been studied in various concentrations of $NiCl_2-methanol$ solvent medium. The volume distribution coefficients with Amberlite CG-400, $Cl^-$form have been measured in these medium. Several synthetic mixtures of organic acids were separated quantitatively by elution with a suitable concentration of $NiCl_2-MeOH$ solution suggested by the distribution data. The concentration of organic acids were determined by UV spectrophotometry.

• Korean Journal of Food Science and Technology
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• v.5 no.3
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• pp.178-182
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• 1973

Omija (Schizandra chinmensis Baillon) grown widely in Korea has been used as a traditional drink and as an ingredient in herbal medicine. A determination of the proximate composition, organic acids and major anthocyanins in Omija was made. 1. The proximate composition of Omija showed water to be 84.2%, protein to be 1.1%, fats to be 0.9%, reducing sugars to be 10.9% and total anthocyanins to be 0.2% in terms of weight percent of fresh, ripe Omija 2. Gas chromatography showed citric acid(3.5%), malic acid(1.4%) and succinic acid(0.2%) to be the major organic acids of the fruit. 3. The anthocyanins, the major pigments present in Omija were separated and isolated into 3 fractions using column chromatograph on insoluble polyvinylpyrrolidone. The main anthocyanin was tentatively identified as peonodin 3-glucoside on the basis of its absorptive properties before and after treatments with acid and $AlCl_3$ in the UV and visible ranges.

• Korean Journal of Food Science and Technology
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• v.20 no.3
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• pp.293-302
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• 1988

This study was performed to identify detailed informations on the nonvolatile flavor of Chinese quince fruits, Chaenomeles sinensis koehne. About 72% of the free amino acids were shown to be valine, asparagine, ${\gamma}-aminobutyric\;acid$, aspartic acid and serine. Arginine, tyrosine, methionine and tryptophan were not present. Glutamic acid and glutamine as a amino acid for peptides were the major components, whereas cysteic acid, methionine sulfone and tryptophan were not detected. The nucleotides attained were composed of cytosine, uridine-5'-monophosphate and cytidine-5'-monophosphate, and these were proved to be a very small quantity. Guanosine-5'-monophosphate, inosine-5'-monophosphate and adenosine-5'-monophosphate were not present. The major sugars were shown to be glucose, sorbose, sucrose and fructose. Fructose was the most abundant one among them. A total of 11 organic acids were identified by capillary gas chromatography and capillary gas chromatography-mass spectrometry. The major components identified were tartaric acid and α-ketoglutaric acid. The total content of vitamin C determined was 386.6mg%, and those of ascorbic, dehydroascorbic, and 2, 3-diketo-L-gulonic acid were 28.8mg%, 154.5mg% and 197.3mg%, respectively. Calcium and phosphorus were the major components, while heavy metals such as cadmium, copper and lead were determined to be a small amount. In the result of organoleptic test on the natural and synthetic extract of Chinese quince fruits, the principal taste components consisted of free amino acids, sugars, organic acids, vitamin C and minerals. Five groups mentioned would have a favorable influence upon the taste of fresh Chinese quince fruits.