• Analytical Science and Technology
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• v.16 no.1
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• pp.70-77
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• 2003

The optimum conditions for the residue analysis of hydroxyanilide fungicide fenhexamid on cucumber, strawberry and grape were investigated by gas chromatography equipped with electron capture detector (GC-ECD) and the residual amount was determined by sprayed days before harvest. Each samples were extracted with acetone, filtered and concentrated to 50 mL. The concentrated extracts were transferred to dichloromethane and then thoroughly concentrated. The concentrated phase was loaded on the filtration column stuffed with silica gel and purified with acetone:hexane (5:95, 15:85, v/v) mixed solvent. The regression equation and linearity of the standard calibration curves between 0.05~2.00 ng were as follows : cucumber; Y=312.40X+10.26, $R^2=0.9996$, strawberry; Y=313.33X+5.54, $R^2=0.9998$, grape; Y=253.27X-2.23, $R^2=0.9994$. From the standard additional experiments with 0.10 mg/L and 0.40 mg/L, the average recoveries of cucumber, strawberry and grape were 94.8%, 88.1% and 93.7%, respectively and the detection limits were all the same as 0.01 mg/L. Residual amounts in crops were ranged from 0.01 to 0.58 mg/L.

• Applied Chemistry for Engineering
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• v.23 no.2
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• pp.176-182
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• 2012

The methane dry reforming has received the considerable attention in recent years, mainly as an attractive route to produce synthesis gas (CO, $H_2$) from green-house gases ($CH_4$, $CO_2$) for resources. However, this process has not been commercialized due to the high temperature and catalyst deactivation. In this study, Co-Ru-Zr catalysts supported on $SiO_2$ were studied for the characterization of methane dry reforming reaction and the preliminary data for process development were achieved. The crystal structure of catalysts was measured by XRD, the surface area and pore size were analyzed by BET, and the element composition of catalyst were analyzed by EDS. Conversions of methane and carbon dioxide were analyzed by GC. In addition, reaction rate constants were obtained from the reaction kinetic study and the optimum catalyst size that does not affect mass transfer from reactants was also determined. The selected pellet-type catalyst maintained activation for 720 h at $850^{\circ}C$.

• Journal of Food Hygiene and Safety
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• v.27 no.4
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• pp.332-338
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• 2012

A simple and sensitive analytical method was developed using gas chromatography with electron capture detector (GC-ECD) and gas chromatography-mass spectrometry (GC-MS) for determination of Picoxystrobin in agricultural products (apple, hulled rice, mushroom, pepper, soybean, and mandarin). Picoxystrobin residues were extracted with acetonitrile, partitioned with saline water, and then they were cleaned up on a florisil solid-phase extraction (SPE) cartridge to obtain an extract suitable for analysis by GC-ECD and GC-MS. The method was validated using 6 agricultural product samples spiked with Picoxystrobin at different concentration levels (0.02, 0.05 and 0.5 mg/L). Average recoveries of Picoxystrobin (using each concentration three replicates) ranged 64.0~98.3% with relative standard deviations less than 10%, calibration solutions concentration in the range 0.1~5 mg/L, and limit of detection (LOD) and limit of quantification (LOQ) were 0.005 and 0.02 mg/L, respectively. The result showed that the developed analytical method is suitable for Picoxystrobin determination in agricultural products.

• Journal of Environmental Health Sciences
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• v.47 no.5
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• pp.384-397
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• 2021

Background: With volatile organic compounds (VOCs) containing aromatic and halogenated hydrocarbons such as benzene, toluene, and xylene that can adversely affect the respiratory and cardiovascular systems when a certain concentration is reached, it is important to accurately evaluate the source and the corresponding health risk effects. Objectives: The purpose of this study is to provide scientific evidence for the city of Seoul's VOC reduction measures by confirming the risk of each VOC emission source. Methods: In 2020, 56 VOCs were measured and analyzed at one-hour intervals using an online flame ionization detector system (GC-FID) at two measuring stations in Seoul (Gangseo: GS, Bukhansan: BHS). The dominant emission source was identified using the Positive Matrix Factorization (PMF) model, and health risk assessment was performed on the main components of VOCs related to the emission source. Results: Gasoline vapor and vehicle combustion gas are the main sources of emissions in GS, a residential area in the city center, and the main sources are solvent usage and aged VOCs in BHS, a greenbelt area. The risk index ranged from 0.01 to 0.02, which is lower than the standard of 1 for both GS and BHS, and was an acceptable level of 5.71×10^-7 to 2.58×10^-6 for carcinogenic risk. Conclusions: In order to reduce the level of carcinogenic risk to an acceptable safe level, it is necessary to improve and reduce the emission sources of vehicle combustion and solvent usage, and eco-car policies are judged to contribute to the reduction of combustion gas as well as providing a response to climate change.

• Journal of Food Hygiene and Safety
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• v.30 no.1
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• pp.81-86
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• 2015

The purpose of our paper was to investigate the migration level of 4,4'-MDA(4,4'-methylenedianiline), 2,4-TDA(2,4-toluenediamine), aniline, acrylonitrile and methylmeth acrylate from plastic cookwares into food simulants and to evaluate the safety of each monomers. The test articles for monomers were PA (polyamide) items for 4,4'-MDA, 2,4-TDA and aniline, PU (polyurethane) items for 4,4'-MDA, ABS (acrylonitrile-butadiene- styrene) items for acrylonitrile, and acrylic resin items for methylmethacrylate. All the article samples of 321 intended for contact with foods were purchased in domestic market. 4,4'-MDA, 2,4-TDA and aniline were analyzed by LC-MS/MS (liquid chromatography -tandem mass spectrometer), acrylonitrile by GC-NPD (gas chromatography-nitrogen phos phorus detector) and methyl methacrylate by GC-FID (gas chromatography-flame ionization detector). The migration level of monomers were within the migration limits of Ministry of Food and Drug Safety (MFDS). As a result of safety evaluation, our results showed that the estimated daily intake (EDI, mg/kg bw/day)s were $2.39{\times}10^{-9}$ and $1.20{\times}10^{-9}$ for 4,4'-MDA and 2,4-TDA of PA, $4.32{\times}10^{-9}$ for acrylonitrile of ABS and $2.27{\times}10^{-7}$ for methylmethacrylate of acrylic resin. Reference Dose (RfD, mg/kg bw/day) of acrylonitrile and tolerable daily intake (TDI, mg/kg bw/day) of methacrylate were established respectively as 0.001 by EPA (US Environmental Protection Agency) and as 1.2 by WHO (World Health Organization). When comparing with RfD and TDI, the EDIs of acrylonitrile and methylmethacrylate accounted for $4.32{\times}10^{-4}%$ and $1.89{\times}10^{-5}%$ respectively.

• Journal of Korean Society of Forest Science
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• v.88 no.4
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• pp.490-497
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• 1999

The objectives of this study were to identify aroma characteristics of Tricholoma matsutake(S. Ito et Imai) Sing. growing in different geograghic ranges in South Korea. Mushrooms were collected from 11 major sites which included four sites(Bonghwa, Uljin, Goryung and Chungdo) in Kyongbuk Province, three sites(Changnyung, Hadong and Hamyang) in Kyongnam Province, two sites(Yangyang and Inje) in Kangwon Province, one site(Goisan) in Choongbuk Province, and one site(Namwon) in Chonbuk Province. One of three mushrooms from each site were used for measurements of aromatic characteristics. Aromatic compounds were identified using a dynamic headspace trap method at $40^{\circ}C$ and GC-MSD(gas chromatograph-mass spectrometric detector) method. A total of 25 aromatic compounds were identified. Large variations in the composition and amount of aromatic compounds were noticed. Major aroma compound was 1-octen-3-ol, while methyl cinnamate known as the major aroma compound in matsutake was not detected at all. The total amount of aromatic compounds was highest in Bonghwa, and decreased in the order of Chungdo, Inje, Hamyang, Uljin, and Yangyang. Based on the total amount, kinds and amounts of individual aromatic compounds, the mushrooms from 11 major sites were grouped into following four types : 1) Bongwha Type : the total amount of aromatic compounds was highest, with major compound being 3-methyl 1-butanol. 2) Hamyang Type including Chungdo, Yangyang and Inje : 1-octen-3-of comprised 2/3 of total aromatic compounds, with second major being 3-methyl butanal. 3) Uljin Type : 1-octen-3-ol comprised 94% of total aromatic compounds, with other compounds being almost nothing. 4) Goisan Type including Goryung, Namwon, Changnyung, and Hadong : the total amount of aromatic compounds was lower than other three types.

• Journal of the Korean Chemical Society
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• v.63 no.4
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• pp.246-252
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• 2019

In the system of GC-OTC/FID (Gas chromatography-Open Tubular Column/Flame Ionization Detector), DMSO (Dimethyl sulfide) solvent was used to separate the polar solvents (Alcohols). In this system DMSO was eluted later than the separated polar solvents. At this system to calculate chromatographic factors [adjusted retention time ($t_R^{\prime}=t_R-t_O$), capacity factor{$k^{\prime}=(t_R-t_O)/t_O$} and separation factor {${\alpha}=(t_{R2}-t_O)/(t_{R1}-t_O)$}], dead time($t_O$) is necessary, but the method to calculate it has not been reported yet. Therefore, we have tried to develop $t_O$. To calculate $t_O$, we conversed DMSO retention time (DMSO $t_R$) to logarithm ($f(x)={\log}\;t_{R(DMSO)}{\rightarrow}t_O$, $t_O={\log}$ 9.551=0.980). To confirm the optimization of the developed method, we compared with $CH_4\;t_R$ and ${\ln}\;t_{R(DMSO)}$. Both of the values calculated by $CH_4\;t_R$ and ${\ln}\;t_{R(DMSO)}$ were not suitable in the calculation k' and ${\alpha}$. The developed method in this study{${\log}\;t_{R(DMSO)}$} has satisfied both of the values k' criteria (1${\alpha}(1<{\alpha}<2)$. The developed calculation method in this study was easy and convenient, therefore it can be expected to be applied to these similar systems.

• Journal of Food Hygiene and Safety
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• v.34 no.1
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• pp.65-72
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• 2019

This study was aimed at investigating the levels of the natural preservatives of benzoic, sorbic and propionic acids in cereal grains, nuts and seeds. Benzoic and sorbic acid were analyzed by high-performance liquid chromatography with a diode-array detector (HPLC-DAD) and further confirmed by liquid chromatography-tandem mass spectrometry (LC-MS/MS), whereas propionic acid was analyzed using a gas chromatography-flame ionization detector (GC-FID) and further confirmed by gas chromatography-mass spectrometry (GC-MS). Benzoic, sorbic and propionic acids were found in 44, 22, and 550 samples out of 702 samples, respectively. From the total of 702 samples. The concentrations of benzoic, sorbic and propionic acid were ranged from not detected (ND) to 23.74 mg/L, from ND to 7.90 mg/L, and from ND to 37.39 mg/L in cereal grains, nuts and seeds, respectively. The concentration ranges determined in this study could be used as standard criteria in the process of inspecting cereal grains, nuts and seeds for preservatives as well as to address consumer complaints or trade disputes.

• Journal of the Society of Disaster Information
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• v.11 no.1
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• pp.135-147
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• 2015

Recent underground common utility tunnels are underground facilities for jointly accommodating more than 2 kinds of air-conditioning and heating facilities, vacuum dust collector, information processing cables as well as electricity, telecommunications, waterworks, city gas, sewerage system required when citizens live their daily lives and facilities responsible for the central function of the country but it is difficult to cope with fire accidents quickly and hard to enter into common utility tunnels to extinguish a fire due to toxic gases and smoke generated when various cables are burnt. Thus, in the event of a fire, not only the nerve center of the country is paralyzed such as significant property damage and loss of communication etc. but citizen inconveniences are caused. Therefore, noticing that most fires break out by a short circuit due to electrical works and degradation contact due to combustible cables as the main causes of fires in domestic and foreign common utility tunnels fire cases that have occurred so far, the purpose of this paper is to scientifically analyze the behavior of a fire by producing the model of actual common utility tunnels and reproducing the fire. A fire experiment was conducted in a state that line type fixed temperature detector, fire door, connection deluge set and ventilation equipment are installed in underground common utility tunnels and transmission power distribution cables are coated with fire proof paints in a certain section and heating pipes are fire proof covered. As a result, in the case of Type II, the maximum temperature was measured as $932^{\circ}C$ and line type fixed temperature detector displayed the fire location exactly in the receiver at a constant temperature. And transmission power distribution cables painted with fire proof paints in a certain section, the case of Type III, were found not to be fire resistant and fire proof covered heating pipes to be fire resistant for about 30 minutes. Also, fire simulation was carried out by entering fire load during a real fire test and as a result, the maximum temperature is $943^{\circ}C$, almost identical with $932^{\circ}C$ during a real fire test. Therefore, it is considered that fire behaviour can be predicted by conducting fire simulation only with common utility tunnels fire load and result values of heat release rate, height of the smoke layer, concentration of O2, CO, CO2 etc. obtained by simulation are determined to be applied as the values during a real fire experiment. In the future, it is expected that more reliable information on domestic underground common utility tunnels fire accidents can be provided and it will contribute to construction and maintenance repair effectively and systematically by analyzing and accumulating experimental data on domestic underground common utility tunnels fire accidents built in this study and fire cases continuously every year and complementing laws and regulations and administration manuals etc.

• Food Science of Animal Resources
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• v.27 no.4
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• pp.531-537
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• 2007

Small amounts of trans fatty acids exist naturally in beef and dairy foods. Also, they can be produced in the process of partial hydrogenation to manufacture shortning or margarine. They can provide a better palatability and shelf life. According to the recently studies, trans fatty acids can raise health risk such as heart diseases and coronary artery diseases. They can also increase low-density lipoprotein (LDL) cholesterol and decrease high-density lipoprotein (HDL) cholesterol in the blood plasma, therefore increasing the risk of atherosclerosis and diabetes. The aim of this study was to determine total lipids and trans fatty acids (TFAs) content in processed foods and meat products. The analysis of trans fatty acids was performed in 28 samples of donuts, 18 samples of bakeries, 4 samples of frozen doughs, 2 samples of popcorns, and 4 samples of meat products (ham, sausage, nuget, and bacon). Total lipids in processed foods and meat products were extracted by chloroform-Methanol method and acid digestion, respectively. They were analyzed by gas chromatography using a SP-2560 column and flame ionization detector. The amounts of TFAs per 100 g of foods were 0-3.3% (0.74% on average) in donuts, 0.2-5.8% (1.18% on average) in bakeries, 0.2-6.3% (1.93% on average) in frozen doughs, and 0-5.8% in popcorns. Meat products such as ham, sausage, and nuget analyzed 0.1% of TFAs, respectively and trans fatty acids in bacon were not detected. As a result, the distribution of TFAs in processed foods was widely ranged from O% to 6.3% according to manufacturers and types of products, whereas the content of TFAs in meat products ranged from 0% to 0.1%.