• Analytical Science and Technology
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• v.14 no.3
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• pp.274-285
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• 2001

In this study, the thermal desorption-cryofocusing-gas chromatographic(TD-C-GC) method was developed for determination of volatile organic compounds(VOCs) in ambient air and was applied at the municipal solid waste landfill sites. On-column cryofocusing was possible only with a 100 ml dewars bottle in TD-C-GC method with a stainless steel column. However, high operating pressure was needed for purging VOCs from the absorbent trap, which was able to solve by pressure programming with a electric pressure controller. By using both pressure and temperature programming brought increasing of resolution power in on-column cryofocusing method, but the high pressure caused a leakage of sample tube with repeated use. A loop cryofocusing devise was also developed and compared with the direct on-column method. In loop cryofocusing method, VOCs were concentrated on a 0.8mm i.d. loop which is located between the injector and separation column by using liquid nitrogen. In order to purge VOCs from the absorbent trap, only 0.4 psi of pressure was need in the loop cryofocusing method. Dual detection system was applied for the analysis of VOCs; a FID was used for hydrocarbons and a FPD was used for sulfur-containing compounds. Qualitative analysis was done by on-column cryofocusing GC-MS system. Among the large number of VOCs, toluene was the most abundant. Hydrogen sulfide, dimethyl sulfide, carbon disulfide, dimethyl disulfide and methyl propyl disulfide were detected at landfill site by FPD.

• Journal of Environmental Health Sciences
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• v.44 no.2
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• pp.178-187
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• 2018

Objectives: This study evaluated the odor emission characteristics from a sewage treatment plant near an industrial complex area in Daegu City. Methods: Odor samples were collected from March 2017 to December 2017 and analyzed for specified offensive odor substances. The odor quotient and the odor contribution were calculated. Results: Ammonia, methyl mercaptane, hydrogen sulfide, dimethyl sulfide, acetaldehyde, propionylaldehyde, toluene, xylene, and methylethylketone were detected in all samples for monitoring the specified odor compounds. The result of contribution analysis is that hydrogen sulfide made the highest contribution in all processes, followed by acetaldehyde. Conclusion: The major components of odor can be determined by evaluating their degree of contribution to the odor intensity and the concentration of the individual odor component. To increase the effectiveness of odor reduction, rather than addressing high-concentration odor compounds, policies focused on materials with a high odor contribution are necessary.

• Journal of Environmental Science International
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• v.20 no.8
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• pp.953-962
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• 2011

The covered stream of cities are considered an odor source. Also, the public do not want a wastewater treatment plant(WWTP) near their properties due to the emission of odor emanating from such sources, although they play an important role in urban development. The purpose of this study is to analyze the pattern distribution of the odorous compounds from the Nambu WWTP and Youngho stream in Busan. odor sampled four times were analyzed by instrumental analysis method and indirect olfactory method. The kinds of offensive odorous compounds examined are acetaldehyde, propion aldehyde, hydrogen sulfide, methyl mercaptan, dimethyl sulfide and ammonia. Also, Concentration of air pollutants has been calculated by ISCST3 models. At the result of this study, The Nambu WWTP releases sulfur compounds. And the major odorous were hydrogen sulfide (1,475 ppb) and acetaldehyde (95 ppb) at Youngho stream. The stink which residents feel will point out the Nambu WWTP mainly if the odor is removed with the improvement of a Youngho stream. Accordingly, we should pay more attention to appropriate components to processes in odor reducing plan at Nambu WWTP.

• Journal of dental hygiene science
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• v.9 no.4
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• pp.461-467
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• 2009

The purpose of this study was to find out the degree of self-consciousness of oral malodor, the status of oral hygiene care, some oral examination factors, and measurement values of malodor compounds through conduction oral examination and questionnaire survey, and measuring volatile malodor compounds by instrumental analysis. The data were collected from 155 patients visiting a dental clinic by using a self-administered questionnaire, conducting oral examination for halitosis, and measuring malodor compounds with Oral Chroma. The rate of recognizing their breath as 'somewhat bad' were 80.0% for the female patients and 74.3% for the male, and, however, 14.3% of the male recognized their breath as 'very bad' while 18.8% of the female did not recognized oral malodor, showing statistically significant difference between gender(p=0.004). The average concentrations of volatile sulfur compounds measured by Oral Chroma were 1.65 ng/10 ml for hydrogen sulfide, 1.71 ng/10 ml for methyl mercaptan and 1.66 ng/10 ml for dimethyl sulfide, on the average, respectively, exceeding malodor threshold levels of all 3 compounds, and were significantly higher in the male group than those in the female, also exceeding all threshold levels except hydrogen sulfide values of the female group. The type of oral malodor was the most prevalent for Type I as 23.2%, followed by Type V, Type IV, Type II whileas Type I and Type IV in the female as 30.6% and 25.9% respectively, showing statistically significant difference by gender(p=0.006). The correlations among oral examination indices was the highest between tongue fur score and simplified oral hygiene index, followed by a significant reverse correlation between the number of fixed prosthodontic teeth and the number of dental caries(p=0.000).

• Journal of Periodontal and Implant Science
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• v.30 no.1
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• pp.203-212
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• 2000

Putrefactive activity within the oral cavity is the principal cause of halitosis. The most common intraoral sites of oral malodor production are tongue, interdental and subgingival areas. The other foci may include faulty restorations, sites of food impaction and abscesses. Periodontal disease frequently involves pathological oral malodor, which is caused mainly by volatile sulfur compounds(VSC), such as hydrogen sulfide, methyl mercaptan, and dimethyl sulfide. The purpose of this study is to evaluate the association between oral malodor and periodontal status. Volatile sulfur compounds in mouth air were estimated by portable sulfide monitor($Halimeter^{TM}$). The results were as follows : 1. The levels of volatile sulfur compounds were significantly greater in a periodontitis group than in a control group(P<0.01). The amounts of VSC in mouth air from patients with periodontal involvement were four times greater than those of the control group. 2. The significant positive correlation was found between VSC concentrations and the number of pocket depth above 4mm(P<0.01), but correlation between VSC concentrations and plaque score was not statistically significant(P>0.05). 3. In the periodontitis group, VSC concentrations of pre-treatment significantly decreased after scaling and root planing(P<0.01). 4. No statistically significant correlation was found between VSC concentrations and sex / age in the periodontitis group. The above results indicate that periodontal disease may play a role as an important factor of oral malodor and deep periodontal pockets are a source of volatile sulfur compounds.

• Journal of Korean society of Dental Hygiene
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• v.8 no.1
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• pp.1-12
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• 2008

I investigated the situation of self-realization for oral malodor and real occurrence of it and researched the situation of coincidence by self-administrated questionnaire and real oral malodor of dental hygiene students in Kyeonggi province and Kyeongbuk province to use as a reference data on prevention and treatment of oral malodor. The obtained results were as follows: 1. Concerning the grade of the subjective symptom of oral odor, a little bit oral malodor was the highest by reaching 77.6%, and no oral malodor was 20%. 2. The time when one feels the oral malodor highest was revealed immediately after awakening from the sleep by running up to 88.2%. 3. Concerning the extent of aversion during the occurrence of oral malodor from other people, 57.6% expressed as unpleasant, and 3.5% showed no aversion. 4. Concerning the intention to participate in the prevention program against the oral malodor, 51.8% had intention of it. 5. Hydrogen sulfide 7.61V19.30, methyl mercaptan 9.53V67.90, dimethyl sulfide 58.31V121.37(pF0.05) marked as causing factors in the 132 respondents who answered that they had a little bit oral malodor in comparison with the grade of subjective symptom and the measurement of actual oral malodor. As the above-mentioned results were obtained by limited subjects, the more diversified and precise comparative study is considered to be needed through the classification of various levels of research subjects.

• Journal of Veterinary Clinics
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• v.24 no.2
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• pp.192-196
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• 2007

Oral malodor in companion animals is noticed by owners at first and it makes owners unpleasant. Therefore oral malodor affects the relationship between pet and owner. Oral malodor is produced by some putrefactive bacteria which putrefy proteins to volatile sulfur compounds (VSC) such as methyl mercaptan, hydrogen sulfide and dimethyl sulfide in the food remnants. And oral malodor is mostly consisted with these VSC. On oral examinations in dogs with oral malodor, it is common that plaque and calculus index were increased than normal dogs'. But organoleptic method is subjective to evaluate halitosis, in this study we measured VSC using organoleptic method and portable sulfide monitor to clarify the relationship between halitosis and periodontal disease in dogs with halitosis. And we found that plaque index and calculus index were significantly related with VSC (P<0.05, P<0.05) in measurement using Halimeter. However there was not significant relationship between gingivitis index and VSC. In conclusion, there was the significant, positive relationship between periodontal disease and halitosis.

• Analytical Science and Technology
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• v.19 no.6
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• pp.498-503
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• 2006

A type of dimethyl disulfide gas CRM in the ppb level was developed for the analysis of tracelevel odorous gas in environmental atmosphere. The concentration of dimethyl disulfide($(CH_3)_2S_2$) was $10{\mu}mol/mol$ level in the cylinder filled with nitrogen, 1500 psi. And the variability of the concentration for 2 years was about 0.14% due to the adsorption or instability of $(CH_3)_2S_2$. The gas standards produced simultaneously in 4 bottles and examined by GC-FID were shown with 0.4%, reproducibility of preparation and 0.25%, standard uncertainty due to weighing and purity. The relative expended uncertainty of 1.1%(95% of confidence level, k=2) was assigned to the certified value of $10{\mu}mol/mol$ level of $(CH_3)_2S_2$ after quantitative evaluation on the purity, mixing, weighing, analysis, adsorption and stability of dimethyl sulfide gas.

• Bulletin of the Korean Chemical Society
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• v.5 no.6
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• pp.240-244
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• 1984

8-Oxyquinoline dihydroboronite is prepared by mixing equimolar amounts of 8-hydroxyquinoline and borane-dimethyl sulfide complex in tetrahydrofuran at room temperature and its structure is determined by spectroscopic methods. The reagent is shown to be an extremely mild reducing agent and reduces aldehydes, cyclohexanones, and acid chlorides to some extent. The reagent in the presence of 0.1 equiv of boron trifluoride etherate in tetrahydrofuran at room temperature reduces selectively aldehydes in the presence of ketones, while the reagent in the presence of 1 equiv of boron trifluoride etherate rapidly reduces simple aldehydes and ketones but does not reduce carboxylic acids, esters, and amides.

• Ocean and Polar Research
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• v.39 no.3
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• pp.181-194
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• 2017

The long-term linear trend of global sea-to-air dimethyl sulfide (DMS) flux was analyzed over a 16-year time span (2000~2015), based on satellite observation data. The emission rates of DMS (i.e. DMS flux) in the global ocean were estimated from sea surface DMS concentrations, which were constructed with chlorophyll a (Chl-a) concentrations and mixed layer depths (MLD), and transfer velocity from sea to air, which was parameterized with sea surface wind (SSW) and sea surface temperature (SST). In general, the DMS flux in the global ocean exhibited a gradual decreasing pattern from 2000 (a total of 12.1 Tg/yr) to 2015 (10.7 Tg/yr). For the latitude band ($10^{\circ}$ interval between $0^{\circ}$ and $60^{\circ}$), the DMS flux at the low latitude of the Northern (NH) and Southern hemisphere (SH) was significantly higher than that at the middle latitude. The seasonal mean DMS flux was highest in winter followed by in summer in both hemispheres. From the long-term analysis with the Mann-Kendall (MK) statistical test, a clear downward trend of DMS flux was predicted to be broad over the global ocean during the study period (NH: $-0.001{\sim}-0.036{\mu}mol/m^2/day\;per\;year$, SH: $-0.011{\sim}-0.051{\mu}mol/m^2/day\;per\;year$). These trend values were statistically significant (p < 0.05) for most of the latitude bands. The magnitude of the downward trend of DMS flux at the low latitude in the NH was somewhat higher than that at the middle latitude during most seasons, and vice versa for the SH. The spatio-temporal characteristics of DMS flux and its long-term trend were likely to be primarily affected not only by the SSW (high positive correlation of r = 0.687) but also in part by the SST (r = 0.685).