• Proceedings of the Korea Air Pollution Research Association Conference
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• 2005.11a
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• pp.368-369
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• 2005

• Journal of Korean Society for Atmospheric Environment
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• v.20 no.5
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• pp.647-654
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• 2004

This study examines the local oxidation chemistry of reduced sulfur compounds (RSC) in the urban air. The chemical conversion of RSC (such as DMS, $CS_2,\;H_2S,\;DMDS,\;and\;CH_3SH)\;to\;SO_2$ was modeled using a photochemical box model. For our model prediction of the RSC oxidation, measurements were carried out from an urban monitoring station in Seoul (37.6$^{\circ}$N, 127.0$^{\circ}$E), Korea for three separate time periods (Sep. 17~18; Oct 23; and Oct. 27~28, 2003). The results of our measurements indicated that DMS and $H_2S$ were the dominant RSC with their concentrations of 370${\pm}$140 and 110${\pm}$60 pptv, respectively. The conversion of DMDS to $SO_2$ can occur efficiently in comparison to other RSC, but it is not abundant enough to affect their cycles. The overall results of our study indicate that the photochemical conversion of the RSC can contribute ≶ 20% of the observed $SO_2$.

• Journal of Korean Society for Atmospheric Environment
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• v.25 no.6
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• pp.512-522
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• 2009

In this study, the removal efficiency of trimethylamine (TMA) and four reduced sulfur compounds (RSC) of $H_2S$, $CH_3SH$, DMS, and DMDS was investigated using deionized water as absorbent. To this end, two types of experiments were conducted which include: (1) by passing both RSC and TMA standard gases through water contained in an impinger system and (2) by passing TMA gases through a water spray system. In the former method, TMA standard gases were effectively removed (below detection limit) in all experiments. Likewise, minor fractions of some RSC ($CH_3SH$, DMS, and DMDS) were removed by water in line with theoretical expectations. In addition, the first type of our experiment was extended further to test some commercially available odor treatment products. The results of this test showed that removal efficiencies of RSC $(8.2\pm13.7\sim43.7\pm2.48%)$ were different significantly among 4 kinds of absorbent, while the removal of TMA was consistently good as water. In the second phase of experiment, removal efficiency of TMA was tested by passing its standard gas through a water spray system. The overall results of our study showed that the actual removal efficiency of odorants by water (as sorptive media) approached the values that can be predicted theoretically (by Henry's law).

• Journal of Korean Society for Atmospheric Environment
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• v.27 no.3
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• pp.281-290
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• 2011

In this study, a series of experiments were carried out to measure temporal stability of reduced sulfur compounds (RSCs) in Tedlar bag samples as a function of elapsed storage time. To this end, temporal variability of 4 RSC standard gases ($H_2S$, $CH_3SH$, DMS, DMDS) was measured up to 29 days. For the purpose of comparison, RSC samples were stored in both individual and mixed state. In the case of mixed standard, samples were also examined to allow comparison between light and dark condition. Then results of $CH_3SH$ data were the most stable with the least change in its concentrations through the end of exps (29 days). When compared with previous studies, the extent of stability appeared to be influenced by the initial concentration levels of samples. When the patterns were compared between individual and mixture samples, differences were not significant in the case of $H_2S$ and DMS. The effects of light conditions on temporal stability were seen to be fairly sensitive on most RSC other than $H_2S$. The results of our study confirm that the stability of RSC storage is affected by their involvement in photochemical reactions.

• Food Science of Animal Resources
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• v.34 no.2
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• pp.166-171
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• 2014

The aim of this study is to examine the influences of spices on the amounts and compositions of volatile compounds released from cooked beef patty. Beef patty with 0.5% of spice (nutmeg, onion, garlic, or ginger powder, w/w) was cooked by electronic pan until they reached an internal temperature of $75^{\circ}C$. A total of 46 volatile compounds (6 alcohols, 6 aldehydes, 5 hydrocarbons, 6 ketones, 9 sulfur compounds, and 14 terpenes) from cooked beef patties were detected by using purge-and-trap GC/MS. The addition of nutmeg, onion, or ginger powder significantly reduced the production of the volatile compounds via lipid oxidation in cooked beef patty when compared to those from the control. Also, the addition of nutmeg and garlic powder to beef patty generated a lot of trepans or sulfur volatile compounds, respectively. From these results, the major proportion by chemical classes such as alcohols, aldehydes, hydrocarbons, ketones, sulfur compounds, and terpenes was different depending on the spice variations. The results indicate that addition of spices to the beef patty meaningfully changes the volatile compounds released from within. Therefore, it can be concluded that spices can interact with meat aroma significantly, and thus, the character of each spice should be considered before adding to the beef patty.

• Analytical Science and Technology
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• v.23 no.1
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• pp.24-35
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• 2010

To learn more about the calibration properties of reduced sulfur compounds (RSCs) by the combination of gas chromatography(GC)-pulsed flame photometric detector (PFPD) and thermal desorption method, a series of calibration experiments were conducted on the basis of both internal and external calibration approaches. For these experiments, gaseous standards of 4 RSCs ($H_2S$, $CH_3SH$, DMS, and DMDS) were prepared at two different concentration levels of both low (10, 20, 50,and 100 ppb) and high ranges (100, 200, 500, and 1000 ppb) along with $CS_2$ as an internal standard. First, the external calibration results were compared between fixed standard volume (FSV) and fixed standard concentration (FSC) method. Secondly, FSV-based calibration results were compared between external and internal calibration results. As FSV method suffers from sensitivity variations less significantly than FSC, the former is recommended to maintain the consistency in GC-TD sensitivity for RSC analysis. In addition, when the calibration data were examined in terms of RSE between external and internal calibration data, the results were not consistent enough to show improvements in internal method. Hence, diverse efforts are desirable to optimize the reproducibility in terms of GC-TD sensitivity for RSC analysis.

• Food Science and Biotechnology
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• v.16 no.1
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• pp.1-7
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• 2007

Garlic (Allium sativum L.) contains a specific sulfur compound, the S-allyl derivative of L-cysteine sulfoxide, and has long been known for its antimicrobial activity against various microorganisms, including bacteria, fungi, and protozoa. The principal antimicrobial compound of garlic is S-allyl-L-propenethiosulfinate (allicin) which is generated by an enzyme, alliinase (L-cysteine sulfoxide lyase), from S-allyl-L-cysteine sulfoxide (alliin). This compound exists exclusively in Allium as a major non-protein sulfur-containing amino acid. S-Allyl-L-propenethiosulfinate belongs to the chemical group of thiosulfinates and is a highly potent antimicrobial. The potency of garlic extract is reduced during storage since thiosulfinates are unstable and are degraded to other compounds some of which do not have antimicrobial activity. Diallyl polysulfides and ajoene are sulfur compounds derived from allicin that do possess antimicrobial activity. It was recently found that garlic becomes antimicrobial on heating at cooking temperatures, and that the compound responsible for this is allyl alcohol, which is generated from alliin by thermal degradation.

• Journal of Korean Society for Atmospheric Environment
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• v.29 no.5
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• pp.615-624
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• 2013

In this study, the emission patterns of reduced sulfur compounds (RSC) were investigated using four different types of food samples (boiled egg, milk, canned meat and strawberry) between fresh and decaying stages. To this end, the concentrations of RSCs were measured at storage days of 0, 1, 3, 6, and 9 under room temperature. Four sulfur compounds ($H_2S$, $CH_3SH$, DMS and DMDS) were selected as target compounds along with two reference compounds ($CS_2$ and $SO_2$). Their concentrations were quantified using GC-PFPD equipped with thermal desorption (TD) system. The boiled egg showed the highest concentration of $H_2S$ (3,655 ppb) at D-1, while $CH_3SH$ reached its maximum value of 64.4~78.5 ppb after 3 days. In milk samples, concentration of $CH_3SH$, DMS, and DMDS went up to 487, 16.3, and 578 ppb, respectively with the progress of decay (D-9). In case of canned meat, concentration of $H_2S$ and $CH_3SH$ peaked in the beginning (D-0) such as 345 and 66.6 ppb. In case of strawberry, $CH_3SH$ and DMDS showed the maximum concentrations 135 and 50.5 ppb at D-1, respectively. The olfactometry dilution-to-threshold (D/T) ratio by air dilution sensory (ADS) test showed similar patterns when sum of odor intensity (SOI) was derived via conversion of odorant concentration data. The results of this study confirm that the time of strong RSC emissions is distinguished for each food type between fresh (e.g., strawberries) and decaying conditions (e.g., milk).

• Journal of Korean Society for Atmospheric Environment
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• v.30 no.4
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• pp.319-326
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• 2014

Exhaust gas emitted as a result of the incomplete combustion of biomass in charcoal kilns includes odor compounds as well as other air pollutants such as particulate matters, sulfur and nitrogen oxides, and carbon monoxide. A number of offensive odor compounds affect quality of life. In this study, odor emissions were investigated from biomass burning in a pilot-scale charcoal kiln and a commercial-scale kiln. Complex odor from emission source reached up to 10,000 dilutions to threshold during the study period. Combustion fume was found to contain reduced sulfur compounds, aldehydes, and volatile organic compounds. Hydrogen sulfide and methyl mercaptan were the major odorants which highly contributed to the offensive odor.

• Journal of Korean Society for Atmospheric Environment
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• v.22 no.6
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• pp.929-939
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• 2006

In this study, the concentrations of major odorous compounds including reduced sulfur compounds (DMS, $CS_2$, and DMDS) and aromatic VOC (benzene, toluene, xylene, etc.) were measured continuously using an on-line GC analytical system. Our measurements were made from a residential area of Ansan city during about two weeks period of October, 2004. The highest mean concentrations of reduced S and VOC were recorded as 56.9 ppt of DMS and 21.7 ppb of toluene, respectively. The results of this study generally show that the pollution levels for both types of chemicals are significant relative to previous measurement results reported from comparable sites, if the results are compared simply in terms of the magnitude of the measured concentration data. Moreover, when the relative importance of different compounds is compared in terms of the odor strength, it indicates that the contribution of reduced S compounds may be much more important than that of VOC in the study area.