• Korean Journal of Food Science and Technology
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• v.38 no.5
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• pp.621-627
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• 2006

To characterize aroma properties of burnt beef reaction flavor manufactured by extrusion, volatile flavor compounds and aroma-active compounds were analyzed by simultaneous steam distillation and solvent extraction (SDE)-gas chromatography-mass spectrometry-olfactometry (GC-MS-O). Hydrolyzed vegetable protein (HVP) was successfully extruded with precursors (glucose, cystine, furaneol, thiamin, methionine, garlic powder, and lecithin) at $160^{\circ}C$, screw speed of 45 rpm, and feed rate of 38 kg/hr. Sixty eight volatile flavor compounds were found in burnt beef reaction flavor. The number of volatile flavor compounds decreased significantly when HVP was extruded either with furaneol-free precursors or without precursors. Twenty seven aroma-active compounds were detected in burnt beef reaction flavor. Of these, methional and 2-methyl-3-furanthiol were the most intense aroma-active compounds. It was suggested that furaneol played an important role in the formation of burnt beef reaction flavor.

• Archives of Pharmacal Research
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• v.21 no.6
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• pp.698-702
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• 1998

Propentofylline (PPF, 3-methyl-1-(5-oxohexyl)-7-propylxanthine) has been reported to be effective for the treatment of both vascular dementia and dementia of the Alzheimer type. The pharmacological effects of PPF may be exerted via the stimulation of nerve growth factor, increased cerebral blood flow, and inhibition of adenosine uptake. The objectives of this experiment are to determine the kinetic behavior of PPF, to identify, and to quantify its metabolite in human. Blood samples were obtained from human volunteers following oral administration of 200mg of PPF tablets. For the identification and quantification of the metabolite, 3-methyl-1-(5-hydroxyhexyl)-7-propylxanthine (PPFOH), PPFOH was synthesized and identified by gas chromatography/mass spectroscopy (GC/MS) and $^1H$-nuclear magnetic resonance spectroscopy. The molecular weight of synthesized metabolite is 308 dalton. The PPF and PPFOH in plasma were extracted with diethyl ether and identified by electron impact GC/MS. The plasma concentrations of PPF and PPFOH were determined by gas chromatography/nitrogen phosphorus detector in plasma and their pharmacokinetic parameters were determined. The mean half-life of PPF was 0.74 hr. The areas under the curve (AUCs) of PPF and PPFOH were 508 and 460ng.hr/ml, respectively. $C_{max}$ of PPF was about 828.4ng/ml and the peak concentration was achieved at about 2.2 hr ($T_{max}$). These results indicate that PPF is rapidly disappeared from blood due to extensive metabolism into PPFOH.

• The Korean Journal of Food And Nutrition
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• v.17 no.3
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• pp.260-265
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• 2004

Volatile components of pine needle(Pinus densiflora S.) were isolated by purge & trap headspace technique and analyzed by gas chromatography-mass spectrometry(GC-MS). And then volatile components were extracted for 2 hr and 20 hr at the two different temperature settings: room temperature and 60$^{\circ}C$. A total of 61 volatile components were identified by the four different conditions. These compounds are classified into six categories in terms of chemical functionality: 35 hydrocarbons, 16 alcohols, 4 carbonyls, 2 esters, 1 acid and 3 ethers. The major components were ${\alpha}$-pinene(1.5～15.7%), ${\beta}$-myrcene(13.2～15.6%), ${\beta}$-phellandrene(l2.0～16.0%) and cis-3-hexenol(4.0～18.3%). In the comparison of the four extraction conditions, longer extraction can be effective to extract components that have a high boiling point, but proved useless in obtaining low boiling point components. As a result of these experiments under the four different conditions, the 20 hr extraction at room temperature appeared to be the most optimized condition for the analysis of volatile compounds by using the purge & trap headspace technique.

• Bulletin of the Korean Chemical Society
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• v.19 no.2
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• pp.194-196
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• 1998

The metabolism of dromostanolone (2α-methyl-5α- androstan-17β-ol-3-one) was studied in three adult volunteers after oral dose of 20 mg. Solvent extracts of urine obtained after enzyme hydrolysis were derivatized with MSTFA/TMCS and MSTFA/TMIS. The structures of intact drug and its metabolites were determined by gas chromatography/mass spectrometry (GC/MS) in electron impact (EI) mode. The major metabolite (2α-methyl-5α- androstan-3α-ol-17-one), its 3β-epimer, parent compound, and several hydroxylated metabolites including intact drug were detected by comparing total ion chromatograms of control urine with that of the administered sample. Two epimers of 2α-methyl-5α- androstan-3,17β-diol were detected using selected ion monitoring. The maximum excretion of dromostanolone and 2α-methyl-5α- androstan-3α-ol-17-one was reached in 6.2-15 hr. The half-life of intact dromostanolone was 5.3 hr. About 3.0% of the administered amount was found to be excreted within 95 hr as unchanged form.

• Journal of the Korean Applied Science and Technology
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• v.22 no.2
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• pp.136-141
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• 2005

This paper presents applicability of Fenton oxidation to perchloroethylene(PCE) contaminated soil. The initial concentration of PCE was 187mg/kg and Fenton oxidation conditions were 1.0M $H_2O_2$ and 0.5M $Fe^{2+}$. More than 97% of PCE decomposition and 98% of dechlorination were obtained within 5 hrs. It was found that the decomposition of PCE by Fenton oxidation was followed pseudo first order and its reaction coefficient was 0.78 $hr^{-1}$. GC-MS and GC-ECD analysis of reaction intermediates confirmed only the presence of trichloroacetic acid(i.e., 1.0% of initial PCE concentration). Under Fenton oxidation conditions, it was proposed that PCE was decomposed not simultaneously but one by one.

• Journal of Korean Society for Atmospheric Environment
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• v.29 no.6
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• pp.757-772
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• 2013

In this study, a combination of sorbent tube (ST)-thermal desorption (TD)-gas chromatography (GC)-mass spectrometry (MS) was used for quantitative analysis of liquid phase standards of 10 BVOC ((1) (+)-${\alpha}$-pinene, (2) (+)-${\beta}$-pinene, (3) ${\alpha}$-phellandrene, (4) (+)-3-carene, (5) ${\alpha}$-terpinene, (6) p-cymene, (7) (R)-(+)-limonene, (8) ${\gamma}$- terpinene, (9) myrcene, and (10) camphene). The results of BVOC calibration yielded comparatively stable pattern with response factor (RF) of 23,560~50,363 and coefficient of determination ($R^2$) of 0.9911~0.9973. The method detection limit (MDL) of BVOC was estimated at 0.03~0.06 ng with the reproducibility of 1.30~5.13% (in terms of relative standard error (RSE)). Emissions of BVOC were measured from four types of fruit samples ((1) tangerine (TO), (2) tangerine peel (TX), (3) strawberry (SO), and (4) sepals of strawberry (SX)). The sum of BVOC flux (${\sum}flux$ (BVOC) in ng/hr/g) for each sample was seen on the descending order of (1) TX=291,614, (2) TO=2,190, (3) SO=1,414, and (4) SX=2,093. If the results are compared between the individual components, the highest flux was seen from (R)-(+)-limonene (265,395 ng/hr/g) from TX sample.

• YAKHAK HOEJI
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• v.45 no.2
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• pp.220-226
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• 2001

A bioequivalence study of Lovastati $n^{TM}$ tablets (Dong Sung Pharmaceutical Co., Korea) to Mevaco $r^{TM}$ tablets (Choong Wae Pharmaceutical Co., Korea) was conducted according to the guidelines (No. 98-56) of Korea Food and Drug Administration (KFDA). Each tablet contained 20 mg of lovastatin. Eighteen healthy Korean male subjects received each formulation at a lovastatin dose of 80 mg (i.e., four tablets) in a 2 $\times$ 2 crossover study. There was a washout period of a week between the dose of the two formulations. Plasma concentrations of lovastatin acid were monitored by a GC/MS method for over a period of 12hr after each administration. The area under the plasma concentration-time curve from time zero to 12hr (AUC) was calculated by a linear trapezoidal method. The maximum plasma drug concentration ( $C_{max}$) and the time to reach $C_{max}$ ( $T_{max}$) were compiled from the plasma drug concentration-time data. Analysis of variance (ANOVA) of these parameters revealed that there are no differences in AUC and $C_{max}$ between the formulations. The apparent differences between the formulations in these parameters were 4.87 and 8.03% for AUC and $C_{max}$, respectively. Minimum detectable differences (%) at $\alpha$=0.1 and 1-$\beta$=0.8 were 17.84 and 15.36% for AUC and $C_{max}$ respectively. The 90% confidence intervals were -15.30~5.56 and -17.02-0.95% for AUC and $C_{max}$, respective1y. Thus, the criteria of the KFDA guidelines for the bioequivalence was satisfied, indicating Mevaco $r^{TM}$ tablets and Dong Sung Lovastati $n^{TM}$ tablets are bioequivalent.ivalent.ent.alent.ent.

• Korean Journal of Food Science and Technology
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• v.41 no.6
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• pp.603-608
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• 2009

In this study, "Hongro" apples for test samples were selected from a market for aroma analysis. Analysis was done after 1 hr, in a forming headspace while maintaining a temperature of $25^{\circ}C$. First, the complex aroma of the apples was assessed by a Direct Sensory Method. Secondly, the complex aroma was analyzed under individual aroma conditions separated by GC/FID/Olfactometry. Finally, aroma component analysis by GC/MS was performed. Degrees of contribution of aroma components were evaluated by an aroma value calculation considering aroma duration time, frequency, and intensity. The contribution rate (%) of the aroma induction component influencing apple aroma was determined by aroma component analysis and aroma contribution degree. As a result, it was found that the top four components were as follows, by contribution rate (%): acetic acid (23%), 1-hexanol (16%), butyl ethanoate (13%), 4-methoxy-2-methylbutane (9%). These four components constitute the complex aroma tested by the direct sensory method, and was largely recognized by the apple aroma test panel. Consequently, it was found that these components are the key factors in apple aroma. If the mechanism of formation of these components can be found, it could have a significant influence on consumers' acceptance of new varieties of apples.

• Analytical Science and Technology
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• v.22 no.6
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• pp.480-487
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• 2009

The herbicide dicamba (2-methoxy-3,6-dichlorobenzoic acid) in soil and plants was determined by gas chromatography-mass spectrometry (GC/MS). The samples were extracted with diethyl ether at pH 2, and washed with 0.1 N HCl, and then dried. The dried residue was derivatized in 1 mL of 10% $H_2SO_4$-MeOH for 2 hr at $80^{\circ}C$. The reaction mixture was neutralized with 4 mL of sodium bicarbonate solution and reextracted with 5 mL of diethyl ether. After the extract was concentrated, dicamba was determined by GC/MS-SIM mode. There was good linearity above 0.999 in the ranges of the $1.0{\sim}100{\mu}g/kg$. Total 42 sample including 32 soil samples and 10 plants samples were analyzed by developed method. Dicamba was detected in the concentration range of $2.9-123.9{\mu}g/kg$ in 15 samples among 32 soil samples and in the concentration range of $43-33,252{\mu}g/kg$ in 5 samples among 10 plants samples. A cause of the wither and die of the pine trees is suspected to spray dicamba around or directly to them.

• Analytical Science and Technology
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• v.21 no.6
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• pp.510-517
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• 2008

This study has been described the metabolism and excretion in a healthy male urine collected for 26hrs after oral administration of diclofenac. To detect conjugated metabolites of diclofenac, urine sample was acid-hydrolyzed under the conditions of 6M-HCl at over $110^{\circ}C$ for 1hr. During the acidic hydrolysis process, diclofenac and its metabolites were converted into their corresponding lactam-ring through dehydration reaction. As results of chemical conversion by means of hydrolysis, the structures of diclofenac and its metabolites were also changed acidic to basic forms. However, lactam-ring was degraded by hydroxyl ion at basic condition. Thus, the extraction rate of dehydrated diclofenac and its metabolites was not favored at basic condition. For the determination of trace amounts of diclofenac and its metabolites in urine, trimethylsilylation (TMS) with MSTFA was applied and followed by analysis with gas chromatograph-mass spectrometer. In this study, four metabolites that are formed by the hydroxylation of parent drug were mainly detected. Each metabolite was tentatively identified by both interpretation of mass spectra and comparison with previously reported results. In addition, time profile of urinary excretion rate for parent drugs and metabolites was studied. Finally, the metabolic pathway of diclofenac was suggested on the basis of the elucidation of its metabolites and excretion profiles.