• Journal of the Korean Society of Food Science and Nutrition
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• v.44 no.7
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• pp.1016-1027
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• 2015

This study collected 120 figs, classified them into six degrees of maturity according to hardness values, and analyzed contents of organic acids and free sugars. Volatile compounds in figs were investigated using the solid-phase microextraction method of gas chromatography/mass spectrometry. For measurement of texture, elasticity increased up to stage 4 and decreased again. Cohesiveness and brittleness increased with maturation. Organic acids in figs were mainly composed of citric acid, malic acid, and tartaric acid in the final stage. Fructose and glucose were the major sugar components of figs. Fructose content decreased from stage 1 to stage 4 and then increased significantly. One hundred and nineteen volatile compounds were identified in figs, and classes were 14 acids, 15 alcohols, 23 aldehydes, 10 esters, 33 hydrocarbons, 11 ketones, four aromatics, six miscellaneous, and five terpenes. The dominant volatile components in figs were hexadecanoic acid, hexane, dodecanal, DL-limonene, 2-hexanal, nonanal, and 6-methyl-5-hepten-2-one.

• Journal of Environmental Science International
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• v.11 no.10
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• pp.1109-1116
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• 2002

This study analyzed concentrations of volatile organic compounds (VOCs) produced from incineration of papers at $600^{\circ}C$. The papers used in this study included A4 papers (new, printed with ink-jet, printed with carbon), newspapers (printed with bean oil, printed with a general newspaper ink), packaging box, document envelope, single-use paper cup, and cosmetic tissue. Papers were heated from room temperature upto $600^{\circ}C$ providing air inside of the electric furnace and then they were oxidized for 80 minutes at $600^{\circ}C$ maintaining the same air supply. VOCs emitted from the incineration process were sampled using an air sampling pump and bags for 160 minutes and then the components and concentrations of the VOCs were analyzed by a CC-MS. The most prominent chemical structure of the Vous identified from incineration of the papers was furans and then furans were followed by aromatics and aliphatic alkenes. About 40% of the identified VOCs contained double bonds, which have relatively a high ozone (ground level) formation potential, within their molecular structure. Also, some cancer suspecting compounds like benzene, dichlorormethane and chloroform were identified.

• Environmental Analysis Health and Toxicology
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• v.17 no.3
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• pp.197-205
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• 2002

Volatile organic compounds (VOCs) are an important public health problem throughout the world. Many important questions remain to be addressed in assessing exposure to these compounds. Because they are ubiquitous and highly volatile, special techniques must be applied in the analytical determination of VOCs. Personal exposure measurements are needed to evaluate the relationship between microenvironmental concentrations and actual exposures. It is also important to investigate exposure frequency, duration, and intensity, as well as personal exposure characteristics. In addition to air monitoring, biological monitoring may contribute significantly to risk assessment by allowing estimation of absorbed doses, rather than just the external exposure concentrations, which are evaluated by environmental and personal monitoring. This study was conducted to establish the analytic procedure of VOCs in air, blood, urine and exhaled breath and to evaluate the relationships among these environmental media. The subjects of this study were selected because they are occupationally exposed to high levels of VOCs. Environmental, personal, blood, urine and exhalation samples were collected. Purge ＆ trap, thermal desorber, gas chromatography and mass selective detector were used to analyze the collected samples. Analytical procedures were validated with the“break through test”, 'quot;recovery test for storage and transportation”,“method detection limit test”and“inter-laboratory QA/QC study”. Assessment of halogenated compounds indicted that they were significantly correlated to each other (p value < 0.01). In a similar manner, aromatic compounds were also correlated, except in urine sample. Linear regression was used to evaluate the relationships between personal exposures and environmental concentrations. These relationships for aromatic and halogenated are as follows: Halogen $s_{personal}$ = 3.875+0.068Halogen $s_{environmet}$, ($R^2$= .930) Aromatic $s_{personal}$ = 34217.757-31.266Aromatic $s_{environmet}$, ($R^2$= .821) Multiple regression was used to evaluate the relationship between exposures and various exposure deter-minants including, gender, duration of employment, and smoking history. The results of the regression model-ins for halogens in blood and aromatics in urine are as follows: Halogen $s_{blood}$ = 8.181+0.246Halogen $s_{personal}$+3.975Gender ($R^2$= .925), Aromatic $s_{urine}$ = 249.565+0.135Aromatic $s_{personal}$ -5.651 D.S ($R^2$ = .735), In conclusion, we have established analytic procedures for VOC measurement in biological and environmental samples and have presented data demonstrating relationships between VOCs levels in biological media and environmental samples. Abbreviation GC/MS, Gas Chromatography/Mass Spectrometer; VOCs, Volatile Organic Compounds; OVM, Organic Vapor Monitor; TO, Toxic Organicsapor Monitor; TO, Toxic Organics.

• Analytical Science and Technology
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• v.18 no.6
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• pp.542-551
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• 2005

This study is to investigate the characteristics of emission concentration according to wallpaper sort and emission time using small chamber method. The target compounds included 45 VOCs and formaldehyde, which were respectively determined by adsorption sampling and thermal desorption coupled with GC/MS method, and by sampling in DNPH cartridge and HPLC method. The emission factor of TVOC and HCHO was detected to $1.1mg/m^2{\cdot}h$ and $0.01mg/m^2{\cdot}h$ respectively, and the wallpapers of 25 satisfied emission standard. TVOC emission factor appeared in order of the concentration of PVC, natural, and Non-PVC wallpaper, while HCHO was detected very low concentration without relation to wallpaper sort. The paraffin hydrocarbons appeared to be the most contributable class of hydrocarbons in terms of their concentrations, followed by aromatics, and olefins, halogenated hydrocarbons was not detected. PVC wallpapers plentifully emitted TVOC above other wallpapers, and toluene was showed higher concentration of 10 times than natural wallpaper. In addition to, emission factor according to elapse was gradually decreased.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.12 no.7
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• pp.3317-3326
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• 2011

Physicochemical properties of Achyranthes japonica and Smilax china extracts were investigated for the purpose of functionality research on the natural bio-resources. Extraction contents were order of distilled water>methanol>ethanol solvent, the highest free aminoacids were proline from Achyranthes japonica, phosphoserine and glutamic acid from Smilax china, respectively. BI and TAC by spectrophotometric absorbance were order of methanol>ethanol>water in Smilax china leaf extract, but water>methaol>ethanol in Achyranthes japonica leaf extract. EDA was high in ethanol extract from Smilax china leaf and in methanol extract from Smilax china root, and in water extract from Achyranthes japonica. TBA value of Achyranthes japonica leaf and Smilax china leaf-ethanol extracts on olive oil was 82.1% and 84.0%, respectively, for that of an artificial antioxidant BHT. Antimicrobial effect was observed in Achyranthes japonica stem-methanol extract on Bacillus subtillis, in Smilax china leaf-ethanol extract on Bacillus subtillis, Vibrio vulnificus and Salmonella enterica, respectively. And the adsorption of Pb(II) on Achyranthes japonica was higher than that of Cd(II) on Smilax china under the same metal ion concentration.

• Journal of Soil and Groundwater Environment
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• v.6 no.3
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• pp.73-91
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• 2001

compounds (VOCs) were selected for assessment of VOCs contamination in some urban runoff and groundwater samples in Seoul. They included 3 aromatic hydrocarbons, 13 alkyl benzenes, 1 ether, 26 halogenated alkanes, 10 halogenated alkenes, and 9 halogenated aromatics. The levels of VOCs in urban runoff and groundwater were measured for samples collected in March 2000, June 2000 and November 2000 in Seoul City. A total of 78 samples (44 run-off water, 27 groundwater, and 7 samples from 4 urban wastewater treatment plants in Seoul) were collected and analysed by GC-MS with purge and trap. After examination of the runoff, it was concluded that alkyl benzenes and aromatic hydrocarbons were organic compounds which were significantly impacted by traffic flows in Seoul. Of 62 VOCs, only 11 VOCs were not detected in runoff samples, while 14 VOCs were detected in 27 groundwater samples. The toluene content in the runoff was extremely variable from 0.1ppb to 29,310ppb, depending on the different sampling sites. The concentrations of xylene ranged between 0.07ppb and 2970ppb in the runoff. The concentrations ranged from 0.05ppb to 33.0ppb for benzene, 0.05ppb to 960ppb for ethylbenzene, 0.08ppb to 20ppb for trichloromethane (chloroform) , 0.03ppb to 4.30ppb for trichloroethylene(TCE) and 0.1ppb to 50ppb for 1,1,2-trichloroethane. From the preliminary study of groundwater from some wells in Seoul, the most frequently detected VOCs are djchlorornethane(methylene chloride), trichloromethane(chloroform) and toluene. Most of aromatic hydrocarbons, alkyl benzenes and other solvents generally lower than detection limits.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.27 no.1
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• pp.59-69
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• 2017

Objectives: The objective of this study is to evaluate the exposure of VOCs and effects of the chemicals on the nail technicians whose works in a nail shop. Methods: For four month from May to August in 2016, we measured twenty-two kinds of VOCs in ten nail shops and carried out health examinations on thirty-four workers in there. Results: The TVOC concentration in indoor air of nail shops is $0.487mg/m^3$ at a minimum and $33.236mg/m^3$ at a maximum where it consists of 70.5% of Ketones, 25.4% of Alcohols, 2.6% of Esters, 0.8% of Aldehydes and 0.7% of Aromatics. The VOCs concentration during nail art works shows an increase in average ratio 1.8 compared to the concentration of indoor air quality and also the concentration of Isopropanol rose with 3.2 of the highest ratio. The results of Spearman correlation between TVOC concentration in indoor air and environmental factor was like that has significance level of correlation(${\rho}$<0.05, r=0.682) in case of number of customers per day, but the other factors were not meaningful in correlation. Correlation between VOCs and medical check-up items was like that has positive significance level(${\rho}$<0.01, r=0.638) between isopropanol and GPT, but the others have not meaningful. The exposure level of VOCs was not exceed the criteria exposure level 1 of working environment measuring method which announced by labor ministry in all ten nail shop indoor air quality. Conclusions: In this study although it was not significant correlation between harmful substances and medical check-up items in the nail shop indoor air quality, it is necessary to do more ventilation and to install exhaust facilities because of existing high VOCs concentration in the nail shop indoor air.

• Applied Chemistry for Engineering
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• v.25 no.1
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• pp.116-120
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• 2014

Light cycle oil (LCO), one of the by-products of the catalytic cracking gasoline manufacturing process, contains a lot of valuable aromatics. In particular, 2,6-dimethylnaphthalene (2,6-DMN) contained in LCO has been becoming important as the basic material of polyethylene naphthalate plastic and liquid crystal polymer, etc. If it were possible to separate and purify the valuable aromatic hydrocarbons (such as 2,6-DMN) from LCO, which have only been used as fuel mixed with heavy oil, it would be very meaningful in terms of the efficient use of resources. We investigated the high-purity purification of 2,6-DMN by the combined method of melt crystallization (MC) and solute crystallization (SC). The enriched DMN isomer mixtures (concentration of 2,6-DMN : 10.43%) recovered from LCO by distillation-extraction combination and the crystal recovered by MC used as raw materials of MC and SC, respectively. The solvent of SC used was a mixture of methanol and acetone (60 : 40 wt%). The crystal of 2,6-DMN with a high-purity of 99.5% was recovered by MC-SC combination. We confirmed that the MC-SC combination was one of the very useful combinations for the high-purity purification of 2,6-DMN contained in the enriched DMN isomer mixtures.

• Food Science and Preservation
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• v.14 no.2
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• pp.136-141
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• 2007

The effects of various concentrations (0.01% 0.02% both v/v) of a Turmeric (Curcuma aromatica Salab.) ethanol extract (CE) on the shelf life of tofu were investigated during tofu storage for 12 d at $25^{\circ}C$. The total number of bacteria in tofu containing 0.02% CE was ca. 100 1,000-fold lower than that of the control after this period Tofu containing CE had a lower pH then did control curd, but was higherin titratable acidity, during the storage period. Measurement of hardness, cohesiveness, and springiness of tofu containing CE were higher than those of control during storage. Each of these parameters of texture value improved (increased) with an increase in the concentration of CE in tofu The degree of whiteness of tofu did not differ between samples with or without CE. The yellowness of tofu increased after addition of CE. The overall acceptability of tofu containing CE was lower than that of control.

• Applied Chemistry for Engineering
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• v.35 no.2
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• pp.107-114
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• 2024

In order to produce high-yield pitch-based activated carbon, pitch was synthesized by blending pyrolysis fuel oil (PFO) and coal-tar. Pitch was synthesized by varying the amount of coal-tar from 0~20% compared to PFO and reacting at 380~420 ℃ for 3 h. The synthesized pitch had a softening point between 80 and 260 ℃, and yields ranged from 10 to 40%. At all synthesis temperatures, as the coal-tar blending ratio increased, the yield increased and the softening point decreased. After considering the selected pitches (softening points: 230~260 ℃), pitches containing coal-tar were more volatile at a low boiling point and had a higher residual carbon content. This is a difference in the composition of coal-tar and PFO, and it was con- firmed that coal-tar has a lot of aromatics and PFO has a lot of aliphatics. The selected pitch was heated to 950 ℃ in a tubular reactor and physically activated with steam for 1 hour. Activated carbon containing coal-tar showed higher yield and microporosity compared to only PFO. In this study, the effect of increasing activated carbon yield by blending pitch raw materials was confirmed, and the physical activation characteristics according to the coal-tar mixing ratio were examined.