• Analytical Science and Technology
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• v.20 no.5
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• pp.361-369
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• 2007

Uncomfortable odor emitted from air conditioning system is the main cause of indoor air quality deterioration. To solve evaporator odor problems, odor active compounds, have to be identified then the quality of the product can be improved its quality. Because evaporator odor in exhaust gas has low odor intensity and discontinuity, it is very difficult to collect and analyze sample. In this study through the identification of odor compounds in condensed water, the evaluation of the eraporator was tested. Odor compounds were extracted from water by headspace-solid-phase microextraction (HS-SPME) method. The single odor was separated by GC/FID/Olfactometry (GC/FID/O) and odor active compounds were identified by GC/AED and GC/MS. Compared to air sample, result of sensory evaluation and the single odor compound appeared similarly. It was identified that odor active compounds have functional group containing oxygen such as alcohols and acids. Evaluation method of odor active compounds using condensed water in evaporator appeared effective on the side of simplicity of collection, low expanse and rapid analysis.

• Journal of Food Hygiene and Safety
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• v.9 no.1
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• pp.1-13
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• 1994

A Simultaneous determination method was improved for the determination and confirmation of zeranol, zearalenone, as well as their isomers and metabolites, in beef. The analytes were extracted from tissue by CH3CN, hydrolyzed enzymatically(for glucuronide conjugates), cleaned up by a strong basic anion exchange resin combined with a liquid/liquid partitioning, derivatized using MSTFA and confirmed, quantified by GC/MS/SIM with a internal standard, zearalane. The results were as follows : (1) all the estrogens were separated on the GC/MS chromatogram under the extraction method and the chromatographic conditions improved, the retention times of zearalane-TMS2, zearalanone-TMS2, zearalenone-TMS2, zeranol-TMS3, taleranol-TMS3, and $\alpha$-zearalenol-TMS3, $\beta$-zearalenol-TMS3, were 18.49, 19.44, 19.63, 19.71, 19.79 and 19.99, 20.08 minutes, respectively. (2) The calibration curves of residual zeranol, zearalenone and their metabolites showed constantly linear(r=0.99) in the range of 5~20 ng. The minimum detection concentration of residual zeranol, zearalenone and their metabolites was 1 ppb. (3) The total average recovery of residual zeranol, zearalenone and their metabolites from spiked beef was 60.2%(CV=29.7%) at the 1 ppb and 63.5%(CV=26.5) at the 2 ppb, 72.9%(CV=18.2%) at the 4 ppb. (4) The preservation method for 6 estrogens was improved for the fast running time(21 min) and MSTFA was utilized for derivatizing 6 estrogens for improvement of recovery, for good resolution, for characteristic mass spectra unlike Jose's method and Tina's method. The utilization of zearalane as internal standard showed good quantification result for zeranol, zearalenone, as well as their isomers and metabolites, in beef.

• Polymer(Korea)
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• v.39 no.2
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• pp.240-246
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• 2015

Formation of a strong 3-dimensional interfacial network structure via chemical reaction between hydroxyl group on silica surface and NR chain by the addition of bis(triethoxysilylpropyl)tetrasulfide (TESPT) into silica-filled NR compound was observed by using Py-GC/MS and SEM. Addition of TESPT into silica-filled NR compound decreased scorch time ($t_{10}$) due to increased sulfur content, and reduced cure rate index (CRI) via continuous reaction between sulfur atoms in TESPT, which acted as a sulfur donor, and activators and/or accelerators. Addition of TESPT in the compound improved processability and mechanical properties of the compound. Overall, we observed that the addition of TESPT into the silica-filled NR compound formed a silica-TESPT-NR network, and thus the degree of crosslinking was increased resulting in improved mechanical properties.

• Journal of Integrative Natural Science
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• v.1 no.2
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• pp.115-121
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• 2008

This study was performed to examine the effect of ${\gamma}$-irradiation on the volatile organic compounds of Cuscutae Semen (Cuscuta chinensis L.). The volatile organic compounds of non-irradiated and 10 kGy ${\gamma}$-irradiated Cuscutae Semen were isolated using SDE apparatus and analyzed by GC/MS. Limonene, ethanol, (E)-2-decenal, hexadecanol, nonanoic acid and nonanal were detected as dominant compounds. Before irradiation, the total concentration of volatile organic compounds of Cuscutae Semen was approximately 189.90 mg/kg. After irradiation at 10 kGy, total concentrations increased to 299.46 mg/kg, but, the profile of volatile compounds including the essential oils of Cuscutae Semen was not differ from non- and irradiated sample. Therefore it was improved the extraction yield of useful compounds such as limonene, menthol, piperitone and isomenthone by irradiation.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.67 no.9
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• pp.1232-1238
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• 2018

This paper proposes methods for improving mass spectral resolution for a gas chromatograph mass spectrometer. The slope signs of the 1st and 2nd fitting functions for the ion signal block of each mass index are obtained, and the unnecessary element signals in the ion signal block are removed. The spectrum can be obtained by obtaining the second-order fitting function of the reconstructed ion signal block using only the effective ion signals. In addition, the resolution of the mass spectrum can be improved by correcting the error caused by the shift of the spectral peak position. To verify the performance of the proposed methods, computer simulations were performed using the actual ion signals obtained from the GC-MS system under development. Simulation results show that the proposed method is valid.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.24 no.6
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• pp.261-267
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• 2014

In this study, we manufactured melting temperature controllable modified surfur (MS) and studied the properties of sulfur modified cement concrete (SMC). We investigated the effects of sulfur and pyridine content on melting temperature of MS. The reaction is confirmed by measuring Raman spectrophotoscopy. The SMC was produced at Water (W)/Cement (C) = 45 wt%, Sand (S)/Aggregate (A) = 45 wt% and 5, 10, 15 and 20 % of MS on the basis of conventional portland cement, respectively. And then physical properties such as compressive strength, splitting tensile strength and permeability of SMC were measured. As MS added, permeability was decreased, while strength and spalling properties were improved. To confirm the safety of MS and SMC, pyrolyzed gas chromatography (P-GC) and gas hazard test were conducted. The results showed that MS and SMC were relatively safe at an elevated temperature.

• Journal of the Korean Chemical Society
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• v.39 no.8
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• pp.635-642
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• 1995

Improved sample introduction system has been investigated for the determination of volatile organic compounds in water using a purge & trap preconcentration apparatus and a capillary gas chromatography/mass spectrometry. The present limitations associated with the moisture control module and cryorefocusing system suggested by EPA were discussed. To solve the problems such as improper separation of peaks due to the adsorption of water and contamination of purge & trap system, a more efficient connection system between the purge & trap apparatus and the gas chromatograph was introduced and the optimum operational conditions were suggested. A carbopack B/carboxen 1000 and 1001 trap was used for the purge & trap procedure and a custom made crosslinked dimethyldiphenylpolysiloxane capillary column was used for the separation of compounds. Accuracy and precision of the method suggested in this report were examined and the method detection limit of each compound was proposed for the simultaneous determination of 54 volatile organic compounds in water.

• Journal of the Korea Organic Resources Recycling Association
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• v.16 no.4
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• pp.57-63
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• 2008

The characteristics of the bio-oil produced by the pyrolysis process with pig feces was investigated in this paper. The continuous auger-type reactor produced bio-oil was maintained at the temperature range of 400 to $600^{\circ}C$, which was higher than a typical that in a conventional pyrolysis system. The pig feces was used as the feedstock. The bio-oil and its compositions were characterized by water analysis, heating values, elemental analysis, bio-oil compounds, by Gas Chromatography/Mass Spectrometry (GC/MS), and functional group by $^1H$ NMR spectroscopy. It was found that the maximum bio-oil yields of 21% w.t. was achieved at $550^{\circ}C$. This result suggested that this auger reactor might be a potential technology for livestock waste treatment to produce bio-oil because it is able to be improved to reach higher efficiency of bio-oil production in further study. The pyrolysis system reported herein had low heat transfer into the feedstock in the auger reactor so that it needs improve the heat conduction rate of the system in further study.

• Food Engineering Progress
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• v.13 no.1
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• pp.38-43
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• 2009

In this research, the contents of capsaicin and dihydrocapsaicin in various species of red pepper produced in the Goesan-gun County were determined by GC-MS. Further, the contents of capsaicin and dihydrocapsaicin in powdered red pepper products with very hot, hot, normal and mild taste were analyzed to present the degree of hot taste in their products based on contents of capsaicin. The contents of capsaicin in each species of red pepper were from 25.18 mg%(Daetong) to 123.62 mg%(Cheongyang). In the powdered red pepper sold in the market, the contents (mg%) of capsaicin in very hot, hot, normal and mild taste products were 101.98, 67.63, 37.74, and 14.73, respectively. Based on this result, the classification of hot taste by contents of capsaicin was presented in the 7 grades. Namely, the products currently sold in the market were classified into very hot, hot, normal and mild taste. In this research, the degree of hot taste was classified based on contents of capsaicin into 1st grade over 120 mg%, 2nd grade in 100-120 mg%, 3rd grade in 80-100 mg%, 4th grade in 60-80 mg%, 5th grade in 40-60 mg%, 6th grade in 20-40 mg% and 7th grade below 20 mg%. Thus, it is expected that the problem which arises when preparing the products such as kimchi, gochujang and seasoning sauces by using powdered red pepper, namely, the inconsistency of hot taste can be improved and maintained.

• Journal of Microbiology and Biotechnology
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• v.3 no.4
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• pp.270-276
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• 1993

We characterized the character impact compounds of flavors of the fermented Korean soy sauce manufactured with both the traditional and the improved Meju made with different strains. The whole flavor samples were obtained by extracting each volatile flavor phase from both the traditional and the improved soy sauce. To get more detailed information, each whole volatile flavor was further fractionated into the basic, acidic, phenolic and neutral fractions. Each separated peak from the whole and fractionated flavor samples on gas chromatogram was identified by GC/MS and Kovat s retention index, and likewise the aroma of each peak was investigated by a sniffing test with the exercised panel. We were able to identify 15 groups of ingredients with the characteristic soy sauce aroma from the soy sauce made with the traditional Meju and 6 groups from the soy sauce manufactured with the improved Meju made with Aspergillus oryzae. The character impact compounds the two soy sauces were different from each other.