• YAKHAK HOEJI
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• v.44 no.5
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• pp.384-390
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• 2000

Metabolism study of the dye, benzidine, was performed by gas chromatography-mass selective detector (GC/MSD) in the urine of rats orally administered 100 mg/kg benzidine. Urine samples were collected in metabolic cages for 0-24, 24-48, and 48-72 hrs. Ten ml of the urine was extracted with XAD-2 resin and the XAD-2 column was eluted with methanol. After evaporation, benzidine and its metabolites were extracted with diethyl ether (for non-conjugated fraction). For conjugated metabolites, $\beta$-glucu-ronidase was added to the aqueous layer that was incubated for 1 hr at 5$0^{\circ}C$ and the aqueous layer was extracted as in non-conjugated fraction. Aliquot of trimethylsilylated derivatives was applied to the GC/MSD. The mutagenicity of benzidine and its acetylated metabolites was tested by histidine/reversion assay. Five metabolites observed and confirmed either by electron impact and chemical ionization modes of the GC/MSD, or authentic compounds were monoacetyl-, diacetyl-, hydroxyacetyl-, hydroxydiacetyl-, and hydroxy-benzidine. Monoacetyl-benzidine was more potent than benzidine in histidine/reversion assay. This data indicates that monoacetylation of benzidine may be one of the metabolites produced in metabolic activation process.

• Korean Journal of Veterinary Service
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• v.28 no.3
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• pp.285-294
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• 2005

This study was conducted to investigate the extraction method for the determination of organochlorine, organophosphorus and synthetic pyrethroid pesticide residues in beef fat by gas chromatography-mass selective detector(GC-MSD). Twenty one pesticide residues in fat were determined using a simple and rapid procedure based on solid- phase extraction(SPE) clean-up cartridges with octadecyl $(C_{18})-bonded$ porous silica, florisil, $10\%$ deactivated florisil. a tandem $C_{18}$ and florisil and a tandem $C_{18}$ and $10\%$ deactivated florisil. Solvent-solvent extraction using acetonitrile was not satisfied to eliminate fat interference for pesticide residue analysis by GC-MSD, and the recoveries of the method in fat ranged from 16.2 to $57.3\%$ except DDT$(83.2\%)$. The recoveries of SPE methods using a tandem $C_{18}$ and Florisil was $59.6\~123.8\%$ except fenitrothion $(135.2\%)$. the SPE method was verified the satisfactory performance of pre-treatment for pesticide residues analysis in fat by GC-MSD. The efficiency of florisil deactivated with $10\%$ water has been not proved significantly on recoveries of pesticide residues in fat.

• Environmental Analysis Health and Toxicology
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• v.16 no.3
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• pp.121-126
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• 2001

Analytical method of benzophenone (BP) in sediment and soil was developed by gas chromatography/mass selective detector/selected ion monitoring (GC/MSD/SIM). The ultrasonic extraction of US EPA (method 3550B) method and liquid-liquid extraction for sediment and soil samples were used for the analysis of BP from sediment and soil. BP was extracted with n-hexane. Organic layer was washed with 5% sodium chloride solution. 1∼2 l of the concentrated solution of organic layer was applied to GC/MSD. The retention time of BP peak was 11.10 min. Recovery (％) of BP by ultrasonication from sediment and soil samples was 96.0∼100.6％ and 40.0∼83.0％, respectively. Recovery of BP by liquid-liquid extraction was 51∼59％ in soil samples. The detection limit of BP in sediment and soil samples were determined to 0.1 ng/g.

• Korean Journal of Veterinary Service
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• v.29 no.3
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• pp.317-330
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• 2006

This study was conducted to develop the analytical method about simultaneous determination for synthetic antimicrobials in muscle by high performance liquid chromatography - mass selective detector (HPLC- MSD). Solid phase extraction (SPE), matrix solid phase dispersion (MSPD) and liquid-liquid extraction (LLE) have been adapted as pretreatment procedures for HPLC- MSD. Among various solvent tested, methanol was chosen for extraction of synthetic antimicrobials in muscles. For the optimized response, the values of various MS parameters including fragment voltage, drying gas flow, nebulizer pressure, drying gas temperature were verified. The average recovery rates using MSPD and SPE for muscles of bovine and pork were 78.9-127.1% and 78.3-121.7%, respectively. This method was verified the satisfactory performance for fourteen synthetic antimicrobials excepting carbadox in muscle of pork as detection limit of $0.05{\mu}g/g$ on API/ES SIM mode.

• Archives of Pharmacal Research
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• v.27 no.1
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• pp.25-30
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• 2004

Combinatorial homoserine lactone mixtures and individual products were obtained from the methionine-functionalized resin in solid-phase synthesis. The four-step process consisting of a coupling step of an N-Fmoc-L-methionine, deprotection of N-Fmoc group, N-coupling with a carboxylic acid, and cleavage reaction through a polymer supported strategy is described. Gas chromatography-mass selective detector (GC-MSD) techniques provide the most powerful methods for identifying both the combinatorial mixtures and individual products.

• YAKHAK HOEJI
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• v.44 no.5
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• pp.379-383
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• 2000

Stanozolol (STZ, 17$\alpha$-methyl-17$\beta$-hydroxy-5$\alpha$-androstano-(3,2-c) pyrazole), an anabolic steroid, is an abused drug by body-builders or atheletes, as well as medicine for treatment of aplastic anemia and vascular thrombosis. In human volunteers, the major urinary metabolite of STZ was reported to be 3'-hydroxystanozolol that was identified by gas chromatography-mass selective detector (GC/MSD). The objective of this experiment is to investigate the in vitro metabolism of STZ in liver S-9 faction of polychlorinated biphenyl-induced rats. Reaction mixture including STZ as substrate and the S-9 faction was extracted with diethyl ether and quantified by the selected ion monitoring mode of GC/MSD. The selected concentration of substrate STZ is 100 nmole and the selected time for incubation in the reaction mixture was determined to 60 min. The amount of 3'-hydroxystanozolol produced was increased by about 6-fold in the reaction medium including the liver S-9 fraction of polychlorinated biphenyl-induced rats, compared to that of untreated rats. Inhibitors of cytochrome P450, SKF-525A and 7,8-benzoflavone, decreased the production of 3'-hydroxystanozolol by about 89~100% and 65~75%, respectively; In conclusion, hydroxylation of STZ into 3'-hydroxystanozolol is confirmed by GC/MSD and is catalyzed by cytochrome P450.

• KSBB Journal
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• v.18 no.1
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• pp.74-77
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• 2003

A simple, reproducible, and rapid gas chromatographic method for putrefactive metabolite determination in feces was developed. The method involves the direct injection of fecal supernatants into the gas chromatograph, without pretreatment. The mass spectra of these metabolites were obtained using an HP 5971 mass selective detector operated in electron impact (EI) ionization mode. This method produced sharp peaks and allowed the simultaneous determination of fecal putrefactive metabolites.

• Journal of Food Hygiene and Safety
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• v.16 no.1
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• pp.61-65
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• 2001

To investigate the optimum condition of 3-monochloro-1, 2-propanediol(MCPD) analysis, gas chromatography with electron capture detector was used. Determination of MCPD derivatized with phenylboric acid was more effective than that of underivatized MCPD. In derivatization of MCPD with phenyl boric acid, there were no significantly different between boiling for 2min at 9$0^{\circ}C$ and vortexing for 5min at room temperature. Extrelut column was suitable for extraction of MCPD diluted in 20% NaCl solution and recovery rates were higher than direct extraction of MCPD with ethyl acetate. But, the method of direct extraction of MCPD with ethyl acetate was useful for rapid ants qualitative analysis. The sample extracted in soysauce(ganjang) was derivatized with phenylboric acid and analyzed by gas chromatography-mass selective detector. That was confirmed as MCPD-phenylboronate.

• Analytical Science and Technology
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• v.30 no.5
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• pp.240-251
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• 2017

1,1,1,2-Tetrafluoroethane (HFC-134a), which is used as refrigerant in air conditioners, has been recently regulated as a greenhouse gas and is recommended for reuse by refining. It is very important to quantitatively analyze trace impurities present in the refrigerant to evaluate the criteria for reuse. In this study, trace impurities including C, H, Cl, and F, which are difficult to quantify because there are no reference materials, were quantitatively analyzed by a gas chromatograph-atomic emission detector (GC/AED); for this analysis, this was preceded by a qualitative analysis with a GC-mass selective detector (GC/MSD). In addition, the AED response was investigated using a hydrocarbon mixed reference material, which was proportional to the number of atoms in the component. Fifteen refrigerant components were detected as trace impurities in HFC-134a by qualitative analysis of trace impurities including C, H, Cl, and F in the samples. Based on the results of the qualitative analysis, quantitative analysis of trace impurities using AED showed that the highest mole fractions were for the $CHClF_2$ component ($45438.38{\mu}mol/mol$) in one sample and for the $C_2H_2ClF_3$ component ($1311.47{\mu}mol/mol$) in another sample. From this study, it has been shown that it is possible for this analytical method to be applied to the qualitative and quantitative analysis of trace compounds in refrigerants, which are difficult to quantify because of the absence of reference materials.

• Journal of the Korean Society of Food Science and Nutrition
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• v.27 no.4
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• pp.568-573
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• 1998

Volatile compounds in Pinus densiflora were extracted with Likens-Nickerson apparatus for three hours, and were separated and identified by gas chromatography(GC) and mass selective detector(MSD). Twenty six compounds were isolated from Pinus densiflora, identified by GC-MSD and twelve compounds were confirmed by matching retention times of the pure comounds. The main valatile compounds were terpenoids such as limonene(36.2%), $\beta$-pinene(16.9%), $\beta$-myrcene(12.6%) and $\alpha$-pinene(10.9%), and the total amount of these main compounds was 367.9$\mu\textrm{g}$ per 1g of pine twigs.