• Analytical Science and Technology
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• v.17 no.4
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• pp.322-336
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• 2004

The improved derivatization technique of tamoxifen metabolite in human urine is described for the acylation method that they are substituted by derivatization reagent like acyl anhydride for use of gas chromatography/mass spectrometry. The hydroxyl group of tamoxifen metabolite was derivatized by trifluoroacetic anhydride (TFAA), pentafluoroacetic anhydride (PFPA) and heptaflorobutylic anhydride (HFBA). It was investigated to the gas chromatography/mass spectrometry (GC/MS) technique use negative ion chemical ionization (NCI), positive ion chemical ionization (PCI) and electron impact (EI). In acylation of the metabolites of tamoxifen, the effective reaction temperature and time were shown to be at $50^{\circ}C$ for 30 min. The 4-hydroxytamoxifen, which is known to major metabolite of tamoxifen, was not detected in human urine, whileas the hydroxymethoxytamoxifen was detected. We thought that this result was from the single dose of tamoxifen.

• Journal of Microbiology and Biotechnology
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• v.16 no.12
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• pp.1990-1994
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• 2006

Fusarium proliferatum KGL0401 was previously isolated from Physalis alkekengi var. francheti plant roots and exhibited a high GA productivity. A gas chromatography-mass spectrometry (GC-MS) analysis of extracts of the culture fluid of F proliferatum KGL0401 also revealed the presence of $GA_1$, $GA_3$, $GA_4$, $GA_7$, $GA_{20}$, and $GA_{24}$. Therefore, the present study conducted a proteome analysis of waito-c rice treated with the culture fluid of the isolated F proliferatum KGL0401 to identify the protein expression triggered by the GA-containing culture fluid. The results revealed the overexpression of 180 protein spots in the sample treated with the culture fluid. Among them, 75 induced proteins were selected and analyzed by MALDI-TOF (matrix-assisted laser desorption-iorrization time-of-flight) mass spectrometry, followed by database searching, and 51 proteins were identified.

• Journal of Pharmaceutical Investigation
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• v.36 no.2
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• pp.123-129
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• 2006

A method determining the plasma concentration of clotiazepam was developed by using gas chromatography/mass spectrometry with an ion-trap detector and was validated for applying pharmacokinetics to human volunteers orally taken 5 mg dose of clotiazepam. The detection limit was 1 ng/ml and the limit of quantitation was 5 ng/mt. Intraday reproducibility and accuracy bias % were less than 8.2 and 10.2% with inter-day variations for those being within 7.0 and 13.8%, respectively. The recovery of clotiazepam was higher than 87%. The principal pharmacokinetic parameters were determined from the plasma concentration-time plot by non-compartmental or two-compartmental analysis. In non-compartmental analysis, the elimination half-life of 10.4 hr and the area under the curve of 651.3 ng hr/ml were determined, and the maximal concentration (158.6 ng/ml) in the plasma was obtained at 0.56 hr post-dose. The developed method can be appropriate to apply pharmacokinetics and bioequivalence of clotiazepam.

• Environmental Analysis Health and Toxicology
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• v.17 no.1
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• pp.37-51
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• 2002

Eleven phenols including two chlorophenols, eight alkylphenols and bisphenol A were derivatized with isobutylchloroformate to form their isobutoxycarbonyl derivatives. Standard phenol mixture was concentrated for the isobutoxycarbonyl (isoBOC) derivatization and analysed by gas chromatography/mass spectrometry (GC/MS). The recoveries of the derivatization method of alkylphenols, chlorophenols, and bisphenol A were calculated by gas chromatography/mass spectrometry-selected ion monitoring mode using two work-up methods for comparison; shaking and heating method. The linear detector responses were obtained in the concentration range of 5∼400 ng, with correlation coefficients varying from 0.9755∼0.9981. Recoveries of the alkylphenols, chlorophenols, and bisphenol A were determined by gas chromatography/mass spectrometry-selected ion monitoring mode using two work-up methods for comparison ; the US-EPA method and the isoBOC derivatization method, Eleven phenols in water samples were extracted with dichloromethane and then concentrated. Also, solid-phase extraction (SPE) with XAD-4 and subsequent conversion to isobutoxycarbonyl derivatives for sensitive analysis with the selected ion-monitoring (SIM) mode. The recoveries were 85.1∼109.9％ and 90.3∼126.6％ for the US-EPA method and the isoBOC.

• Archives of Pharmacal Research
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• v.16 no.3
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• pp.213-218
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• 1993

($\pm$)-Higenamine is known as a cardiotonic principle of aconite root (root of Aconitum spp., Ranunculaceae). A simple and sensitive detection method for higenamine was developed by using gas chromatography-mass spectrometry (GC/MS). The recovery of higenamine after extraction and concentration with XAD-2 resin column was around 95% from rat biological fluids such as bile, plasma and urine. The limits of detection of higenamine in these biological fluids were approximately 0.1 ng/ml each. It has well been suggested that tetrahydroisoquinolines possessing catechol moiety such as higenamine should be subjected to the catechol-O-methyl transferase (COMT) activity in vivo. We detected two major peaks of presumed metabolites of higenamine in the total ion chromatogram obtained from the rat urine sample after the oral adminstration of ($\pm$)-higenamine. The scan mass spectrum of one of the metabolties coincided with those obtained from coclaurine $(C_6$-O-methyl higenamine) and those of the other metabolite are suggestive of isococlaurine $(C_7$-O-methyl higenamine).

• Bulletin of the Korean Chemical Society
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• v.25 no.10
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• pp.1489-1494
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• 2004

A gas chromatography/mass spectrometric assay method was developed for the determination of persistent organochlorine pollutants (POPs) in hair. For the exact extraction study was used hair of rat exposed with POPs. Sonication of the hair matrix with 3 M HCl solution in methylene chloride of the extraction methods studied was the most efficient and rapid sample preparation method. After sonication of rat hair was achieved clean up with a solid phase extraction procedure using silica gel-florisil. Elution was performed with 8 mL of methylene chloride. The eluate was concentrated to approximately 100 ${\mu}L$ and analyzed by gas chromatography-mass spectrometry (GC-MS). Detection limits of POPs were in the concentration range of 0.6-1.2 ng/g in rat hair. Aldrin, dieldrin, p,p-DDT and mirex were dosed rat for 4 weeks at concentration of 0.01 mg/L in drinking water and detected in rat hair at concentration of 2.8, 11.3, 7.9 and 15.6 ng/g, respectively. Aldrin and p,p-DDT were metabolized to dieldrin and p,p-DDE, which were detected in concentration of 9.7 and 2.9 ng/g in rat hair, respectively. The developed method may be valuable to be used to analyze POPs in human hair.

• Bulletin of the Korean Chemical Society
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• v.30 no.1
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• pp.61-66
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• 2009

An analytical method based on solid-phase extraction and gas chromatography / mass spectrometry has been developed for measurement of acaricides (amitraz, bromopropylate, coumaphos, cymiazole, and tetradifon) in honey sample. In the stability test of acaricides in honey, amitraz underwent a rapid degradation into 2,4-dimethylaniline (DMA), 2,4-dimethylphenylformamide (DMPF), and N-(2,4-dimethylphenyl)-N'-methylformamidine (DMPMF), whileas other acaricides were found to be stable even for over three months. Extraction of five acaricides from 5g of honey sample was carried out by liquid-liquid extraction using 20mL of ethylacetate. For purification, Florisil-SPE cartridge with elution of 5mL of n-hexane/ acetone (55:45, v/v) was found to remove interferences effectively. Quantification was performed using gas chromatography / mass spectrometry in the selected ion monitoring mode. Spiking experiments were carried out to determine the recovery, precision, and limits of detection (LODs) of the method. The overall recovery values from honey spiked at 0.02 and 0.20 ${\mu}g/g$ levels, respectively, were found to be greater than 75% for all acaricides. The method detection limits for acaricides were ranged from 0.1 to 3 ppb. The developed method in this study was applied for the monitoring of acaricides in honey products collected from urban markets in Korea.

• Journal of the Korean Chemical Society
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• v.41 no.10
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• pp.524-534
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• 1997

Analysis of additives in cured rubber is often a difficult task for analytical chemists because of a wide variety of complex components. Conventional analyses of additives and rubbers have been done in multistep, off-line processes with large sample size and extensive sample preparations. The coumarone-indene resin, resorcinol-formaldehyde resin, and prevulcanization inhibitor have been characterized by their pyrolysis pathways and mass spectra of characteristic pyrolyzates. Pyrolysis Gas Chromatography/Mass Spectrometry (Py-GC/MS) was used in the identification of additives without any sample pretreatment. This result shows that several organic additives in cured rubber can be directly analyzed.

• Korean Journal of Food Science and Technology
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• v.7 no.1
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• pp.15-21
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• 1975

Soong-Neung is a Korean traditional beverage served after meals and is made from cooked and roasted rice produced on the bottom of the container during the rice cooking process. The volatiles from the extract of cooked and roasted rice were separated into pyrazine and carbonyl fractions and qualitatively investigated. The pyrazine fraction was characterized by gas chromatography and combined gas chromatography-mass spectrometry and five pyrazines were positively identified. Pyrazine compounds identified are 2-methylpyrazine, 2,3-dimethylpyrazine, 2,5-dimethylpyrazine, 2-ethyl-5-methylpyrazine and 2-ethyl-3-methylpyrazine. Carbonyls were converted to their 2,4-dinitrophenylhydrazones and identified by gas chromatography, combined gas chromatography-mass spectrometry and thin layer chromatography. Acetaldehyde, propionaldehyde, iso-butyraldehyde and iso-valeraldehyde were positively identified in the carbonyl compounds. The aroma of the fractions indentified as 2,3-dimethylpyrazine and 2,5-dimethylpyrazine had a nut-like or roasted cereal-like flavor, which is one of the characteristic flavors of Soong-Neung.

• Food Science and Biotechnology
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• v.15 no.5
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• pp.688-693
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• 2006

Glucosinolates are hydrolyzed by the enzyme myrosinase and are mainly found in cruciferous vegetables such as Chinese cabbage (Brassica campestris L. ssp. pekinensis). lsothiocyanates (ITCs) are glucosinolate degradation products with reported anticarcinogenic properties. Korean Chinese cabbage in the form of 'kimchi' is a staple part of the Korean diet. In this study, we examined the effects of storage temperature and duration on glucosinolate, ITC, soluble sugar, and organic acid levels in kimchi. Changes in pH and the impact of various parts of the Korean Chinese cabbage being used during the preparation of the dish were also assessed. Extracted ITC levels, analyzed via gas chromatography (GC) and GC/mass spectrometry (GC/MS), were higher in the midrib parts than in the cabbage leaves after storage at both 4 and $20^{\circ}C$. During storage, organic acid levels increased while soluble sugars were depleted. The pH initially increased (after 1 day at $20^{\circ}C$, and 1 week at $4^{\circ}C$), but subsequently decreased over time at both temperatures. Glucosinolate and ITC levels increased in the beginning of storage but then generally fell during further storage. Our data suggest that acidity-related reduction in myrosinase activity during storage may decrease glucosinolate and ITC levels. The changes in these levels depended on the storage conditions and the Korean Chinese cabbage parts used for the kimchi preparation.