• Applied Biological Chemistry
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• v.34 no.2
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• pp.149-153
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• 1991

Several commercial soybean oils were stored at $20^{\circ}C,\;40^{\circ}C$ and $60^{\circ}C$ with daily exposure of fluorescent light for 12 hours and evaluated their rancidity by headspace gas chromatographic analysis of pentanal and hexanal. The data of gas chromatographic analysis was compared with organoleptic flavor evaluation. For headspace gas chromatographic analysis, the volatile compounds were recovered by porous polymer trap and flushed into a fused silica capillary column at $250^{\circ}C$, The pentanal and hexanal separated were identified by gas chromatography and gas chromatography-mass spectrometric method. The results showed that the contents of pentanal and hexanal were linearly increased during storage for 100 days. A very simple linear relationship was found between organoleptic flavor scores and amounts of two volatile compounds with very high correlation coefficient. A similar linear relationship was also obtained for acid and peroxide value with sensory data. This results suggested the possible implication of pentanal and hexanal as an quality index for rancidity evaluation of soybean oil.

• Journal of Ginseng Research
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• v.15 no.2
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• pp.117-119
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• 1991

In continuation of previous isolation of two lignan components, Gomisin A and -N, from Korean Red Ginseng the presence of the two lignans was identified in the hexane extract of Korean White Ginseng by gas chromatographic analysis.

• Proceedings of the PSK Conference
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• 2001.10a
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• pp.286.3-287
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• 2001

• Archives of Pharmacal Research
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• v.27 no.5
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• pp.539-543
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• 2004

An efficient analytical method was devised for the accurate L-muscone assay in aqueous samples. It involves solid-phase extraction of L-muscone in adsorption mode using XAD-4 as the sorbent and dichloromethane modified with 10% (v/v) methanol as the eluting solvent. The gas chromatographic analysis of the eluate residue dissolved in toluene on a DB-5MS capillary column provided complete resolution of L-muscone from the co-extracted interferences. The overall method showed excellent linearity ($r^2{\geq}$ 0.9994) in the range of 0.1 to 2.0 $\mu\textrm{g}$/mL with good intra- and inter-day precisions (% RSD = 2.5～7.3) and with high extraction recovery rates ($\geq$ 98.1 %). When the present method was applied to a L-muscone herbal drink product, the within-batch RE (%) in the labeled concentration (1.5 $\mu\textrm{g}$/mL) for the three randomly chosen bottles were -2.4, -1.3 and -3.3 with high precision (% RSD $\leq$ 3.1). The present method is considered to be suitable for quality control evaluation on liquid drinks and other complex formulations fortified with L-muscone.

• YAKHAK HOEJI
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• v.30 no.5
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• pp.214-219
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• 1986

A gas chromatographic procedure is described for the quantitative analysis of ephedrine hydrochloride, pseudoephediiiie hydrochloride and norephedrine hydrochloride in pharmaceutical preparations. The procedure was based upon the determination of thioureas formed from amines and phenylisothiocyanate. The recoveries of ephedrine, pseudoephedrine and norephedrine from pharmaceutical preparations were 100.7(S.E. 0.9), 99.5(0.8), 99.1(0.8) and 99.1%(O.9), respectively. The high accuracy and precision of this assay were inherent in the flame photometric detectors normally used in gas chromatography.

• YAKHAK HOEJI
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• v.31 no.6
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• pp.399-401
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• 1987

A gas chromatographic utilizing procedure headspace gas analysis is performed to study effect of malotilate on levels of ethanol and its metabolite acetaldehyde in a blood sample from the rat. The concentrations of ethanol and acetaldehyde were determined simultaneously at 1, 3, and 6h after ethanol administration. Our results would suggest the malotilate could promote clearances of ethanol and acetaldehyde in blood, and could accelerate it, especially, in $CCl_4$ pretreated rats.

• Analytical Science and Technology
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• v.9 no.2
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• pp.123-133
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• 1996

The optimum conditions for the analysis of the difenoconazole fungicide on soil and crops were investigated and the residues of that in apple and soil were identified by using the gas chromatography. The extract with acetonitrile was separated with saturated NaCl and n-hexane solution after filtered, and concentrated. Obtained fungicide residues were transfered to the florisil column and eluted with acetone and n-hexane mixed solution for the analysis by GLC(ECD). From the standard addition experiments with 0.20 and 1.0ppm, the average recoveries were 86~92% and the detection limit was 0.01 ppm. It seems to be safely used when difenoconazole is treated three times until 15 days before harvest of apple. In this case residual amounts of difenoconazole in apple was from 0.037ppm to 0.044ppm. The soil samples extracted with methanol and ammonium hydroxide mixed solution were partitioned with dichloromethane and saturated sodium chloride solution. The organic phase was concentrated and redissolved with toluene and analyzed with GLC(FID) after cleaned with Sep-Pak column. From the standard addition experiments with 0.10, 0.50 and 1.0ppm, the average recoveries were 101.2~103.7% and the detection limit was 0.025ppm.

• Bulletin of the Korean Chemical Society
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• v.20 no.6
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• pp.696-700
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• 1999

A method has been developed for the determination of trace anion impurities in concentrated hydrogen peroxide. The method involves on-line decomposition of hydrogen peroxide, ion chromatographic separation and subsequent suppressed-type conductivity detection. H2O2 is decomposed in Pt-catalyst filled Gore-Tex membrane tubing and the resulting aqueous solution containing analytes is introduced to the injection valve of an ion chromatograph for periodic determinations. The oxygen gas evolving within the membrane tubing escapes freely through the membrane wall causing no problem in ion chromatographic analysis. Decomposition efficiency is above 99.99% at a flow rate of 0.4mL/min for a 30% hydrogen peroxide concentration. Analytes are quantitatively retained. The analysis results for several brands of commercial hydrogen peroxides are reported.

• YAKHAK HOEJI
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• v.37 no.1
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• pp.54-65
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• 1993

A method for the determination of 16 residual pesticides in crude deugs was examined. Crude drug was extracted with acetonitrile/water solution and the extract was partitioned between hexane/CH$_{2}$Cl$_{2}$ and NaCl saturated water. The organic layer was passed through cleanup column and subjected to the GC/ECD or GC/NPD analysis. Essential oil components in crude drug interfere with the analysis, and sulfuric acid treatment was adapted to overcome this interference.

• Korean journal of applied entomology
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• v.16 no.4 s.33
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• pp.221-227
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• 1977

Polychlorinated Biphenyls (PCBs) interfere with gas chromatographic analysis of multiple organochlorine pesticide residues. In the present work, existing Florisil column chromatographic method has been modified as to improve separation of organochlorine pesticides and their metabolites from PCBs. It was amply demonstrated that separation of $\alpha-BHC,\; \gamma-BHC$ Heptachlor epoxide Dieldrin, p.p-DDD, p.p'-DDT from PCBs such as Aroclor 1254 is complete and recovery of the pesticides is found quantitative. Aldrin and Heptachlor in the Aroclor eluant can be separately analyzed by comparison of the chromatographic pattern of standard Aroclor 1254 with that of Aroclor 1254 a dmixed with the two pesticides. The Florsil column technique can be utilized in the routine evaluation of the organochlorine pesticide residues by gas chromatography.