• 한국대기환경학회지
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• 제15권4호
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• pp.417-428
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• 1999

The measurement of VOSCs(volatile organic sulfur compounds) in the air is nowadays a very important environmental research field. It is, however, very difficult because the concentration of the VOSC in ambient air is usually very low and the high reactivity makes it difficult to keep in container without loss of recovery. In this study, sampling method with cryogenic preconcentration is evaluated for analysis of atmospheric VOSC such as $CH_3SH,\;CH_3CH_2SH,\;CH_3SCH_3,\;CS_2,\;CH_3SSCH_3,\;CH_3SCH_2SCHA_3,\;and\;C_2H_5SSC_2H_5$ analyzed by GC-MS or GC-FID. Repeatabilities of measurement accompanied with preconcentration for 3-successive runs were in the range of 0.2~1.0% as a relative standard deviation. Stabilities up to 13 days were measured in 6 L canister and 10 L tedlar bag filled with VOSCs in ppb level. Higher stability was observed in tedlar bag as compared to canister with glass coated inner walls, and thiol compounds show dramatic losses in canister within 2~3 days. It is found that recovery over 70% was obtained in a week for all tested VOSCs when the compounds from ambient air matrix were stored in tedlar bag. It is also found that the stabilities of VOSCs are depending on humidity and coexisting compounds in matrix gas due to sample adsorption onto inner surface and reactivity. The results indicate the possibility and limitations of VOSC analysis in ambient air using container sampling method with cryogenic preconcentration.

• 한국환경보건학회:학술대회논문집
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• 한국환경보건학회 2005년도 국제학술대회
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• pp.399-405
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• 2005

In this study, we investigated the gas chromatography (GC) and pulsed flame photometric detection (PFPD) system for the analysis of four major reduced S compounds including hydrogen sulfide ($H_2S)$; methyl mercaptan ($CH_3SH$); dimethyl sulfide (DMS); and dimethyl disulfide(DMDS) contained in environmental samples. To analyze these compounds in high concentration range (above ppb level), we developed a high mode analytical setting with the loop-injection system. By contrast, we also established a low mode setting for the analysis of low concentration samples (ppt-level samples from ambient air) by the combination with thermal desorption unit(TDU). Comparative analysis of both settings revealed that relative detection properties of four S compounds are systematic enough. The results of high mode analysis indicated that the patterns were systematic among compounds: H2S exhibited the lowest sensitivity, while DMBS showed the strongest one. The results were also compared in terms of sensitivity reductions for all compounds by dividing slope ratios between low and high mode system. Although low mode system exhibited significant reductions on the order of a few tens times, their detection characteristics were highly consistent as it was shown in the high mode setting. To learn more about absolute and relative relations between two different modes of S analysis, future studies may have to be directed to cover more complicated nature of GC/PFPD performance. Hydrogen sulfide($H_2S$) was over in summer about low level of olfactory sense 410 ppt, Methyl mercaptan(C$H_3SH$) was over in apring and summer about low level of olfactory sense 70, Dimethyl sulfide(DMS) was not over in four season about low level of olfactory sense 2,200 ppt. Carbon disulfide($CS_2$) was not over in four deason about Tow level of olfactory sense 210,000, Dimethyl disulfide(DMDS) was not over in summer about low level of olfactory sense2,000.

• 분석과학
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• 제23권1호
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• pp.24-35
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• 2010

본 연구에서는 GC-PFPD와 열탈착 분석기법을 이용한 환원 황화합물(reduced sulfur compounds: RSC)에 대한 열탈착 검량방식의 시간적 재현성을 기존의 외부 검량기법에 덧붙여, 내부표준시료 기법을 연계하여 평가하고자 하였다. 이를 위하여, 4종류의 악취성 황화합물질($H_2S$, $CH_3SH$, DMS, DMDS)과 이들에 대한 내부 표준시료로 CS2를 준비하였다. 이들 표준시료는 저농도(10, 20, 50, 100 ppb)와 고농도 그룹(100, 200, 500, 1000 ppb)을 대표할 수 있게 넓은 범위로 준비하였다. 그리고 외부검량(external calibration)방식의 분석 결과를 부피고정방식(fixed standard volume: FSV)과 농도고정방식(fixed standard concentration: FSC)로 비교하였다. 또한, 2차적으로 FSV 방식의 결과에 외부 및 내부 검량기법을 동시에 적용하여 검량방식의 경시변화(안정도)를 평가하였다. 본 실험의 결과, 감도에 대한 경시변화는 FSC 방식에 비해 FSV 방식에서 작게 나타났다. 따라서 RSC 분석에서 FSV방식이 경시변화를 줄여주는데 상대적으로 효과적이라는 것을 알 수 있었다. 2차적으로 FSV 방식의 결과에 대해 외부 및 내부방식의 감도(기울기 값)를 비교하였다. 이러한 비교를 상대표준편차(RSD)값으로 평가하면, GC-PFPD-TD 시스템의 감도가 비교적 강한 경시변화를 보인다는 것을 알 수 있다. 따라서 이러한 분석기법의 시간적 재현성을 확보하기 위해서는 여러 가지 검정노력이 필요한 것으로 사료된다.

• 한국약용작물학회지
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• 제27권1호
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• pp.24-29
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• 2019

Background: Camellia sinensis L.(CS) is a perennial evergreen species of plant whose leaves are used to produce tea. In this plant species, the parts used are the leaves, sub-branch parts are thrown out. Methods and Results: Ethanol extract of sub-branch parts was used for isolation of major compounds by column chromatography. Structures were identified as caffeine (1), (-)-epicatechin (2) and (-)-epicatechin gallate (3) by interpretation of spectroscopic analysis, including $^1H$- and $^{13}C$-NMR. High-performance liquid chromatography (HPLC) method was used to compare the quantitative level of marker compounds in various extraction solvents of sub-branch parts of CS. The content of caffeine, (-)-epicatechin, and (-)-epicatechin gallate in 30% ethanol extract showed higher value with $3.28{\pm}0.57mg/g$, $5.53{\pm}0.88mg/g$, and $1.29{\pm}0.24mg/g$, respectively. Conclusions: These results indicated that not only leaves parts but also sub-branch, could be a good source for the functional material and pharmaceutical industry.

• 한국조리학회지
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• 제13권1호
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• pp.119-128
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• 2007

식품의 조리과정 중에 부산물로 나오는 갑각류 폐기물을 이용하여 소스를 제조하여 canister system을 이용하여 농축한 후 GC/MSD를 이용해 휘발성 성분을 동정하였다. 그 결과 총 휘발성 성분의 개수는 72종이었으며 그 중 새우를 사용하여 만든 소스의 휘발성 성분이 45개로 가장 많았다. 새우 소스의 휘발성 성분은 10종의 alkane, 4종의 ketone, 3종의 aldehyde 및 7종의 alcohol이었으며 3-methyl-2-butanone, 2-pentanamine, isobutane, 3- methyl-butanal, furan, carbon disulfide, dimethyl sulfide가 주요한 성분이었다. 꽃게 소스에서는 18개의 휘발성 성분이 동정되었고, 4종의 alcohol류, 5종의 alkane류, 3종의 aldehyde류 및 ketone, acid와 amine이 각각 1종 검출되었으며, 2-methoxy ethanol, trimethyloxirane, 3-buten-1-ol이 꽃게 소스에서 주요한 휘발성 성분으로 나타났다. 바다가재 머리부분을 이용한 소스에서 16종의 휘발성 성분이 동정되었으며 alkane류 2종, aldehyde와 alcohol이 각각 1종씩 동정되었고 formic acid, 1-propanethiol, $\beta$-pinene, allyl sulfide가 주요한 향기 성분으로 나타났다. 바다가재 껍질을 이용한 소스에서 휘발성 성분이 18종 검출되었으며, acid류, pentane, 3-methyl 1-butanol 및 2, 4-dimethyl- 3-pentanone이 주요한 휘발성 성분인 것을 알 수 있었다.

• 한국식생활문화학회지
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• 제30권1호
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• pp.86-96
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• 2015

Onions contain antioxidant flavonoids and bioactive sulfur compounds. These substances are more abundant in the peel than in onion flesh. For this reason, whole onions including peels were added to soy milk to produce soy milk with whole onions (SWO), whereas peeled onions were added to soy milk to produce soy milk with peeled onions (SPO). The functional and antioxidant properties of these two kinds of soy milk were then analyzed and compared. Compared to control soy milk (CS) without onion powder, treated samples (to which freeze dried onion powder was added at 1.4, 1.6, 1.8, and 2.0%, respectively) showed significantly increased amounts of quercetin, isoflavone, and total phenol (p=0.05). The magnitude of the increase rose as the amount of added onion powder increased and when onion powder contained onion peels. With regards to antioxidant activity (DPPH and ABTS), SWO showed a greater value than SPO. The sensory evaluation scores of SWO and SPO were lower than CS for roughness and swallowing, as adding onion powder increased solid contents and viscosities. However, higher overall acceptability were obtained 1.8SPO and 1.8SWO.

• Natural Product Sciences
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• 제26권1호
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• pp.64-70
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• 2020

Citrus junos seeds (CS) have been traditionally used for the treatment of cancer and neuralgia. They are also used to manufacture edible oil and cosmetic perfume. A large amount of CS shells without oil (CSS) are discarded after the oil in CS is used as foods or herbal remedy. To efficiently utilize CSS as a by-products, it needs to be studied through chemical analysis. Therefore, we developed an ultra-performance liquid chromatography (UPLC)-diode array detection (DAD) method for simultaneous determination and quantitative analysis of five components (two flavonoids and threes limonoids) in CSS. A Waters Acquity UPLC HSS T3 column C18 (2.1 × 100 mm, 1.8 ㎛) was used for this separation. It was maintained at 40 ℃. The mobile phase used for the analysis was distilled water and acetonitrile with gradient elution. To identify the quantity of the five components, a mass spectrometer (MS) with an electrospray ionization (ESI) source was used. The regression equation showed great linearity, with correlation coefficient ≥ 0.9912. Limits of detection (LOD) and limits of quantification (LOQ) of the five compounds were 0.09 - 0.13 and 0.26 - 0.38 ㎍/mL, respectively. Recoveries of extraction ranged from 97.45% to 101.91%. Relative standard deviation (RSD) values of intra- and inter-day precision were 0.06 - 1.15% and 0.19 - 0.25%, respectively. This UPLC-DAD method can be validated to simultaneously analyze quantities of marker flavonoids and limonoids in CSS.

• Journal of Microbiology and Biotechnology
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• 제33권7호
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• pp.949-954
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• 2023

Type III polyketide synthase (PKS) found in bacteria is known as 1,3,6,8-tetrahydroxynaphthalene synthase (THNS). Microbial type III PKSs synthesize various compounds that possess crucial biological functions and significant pharmaceutical activities. Based on our sequence analysis, we have identified a putative type III polyketide synthase from Nocardia sp. CS682 was named as ThnA. The role of ThnA, in Nocardia sp. CS682 during the biosynthesis of 1,3,6,8 tetrahydroxynaphthalene(THN), which is the key intermediate of 1-(α-L-(2-O-methyl)-6-deoxymannopyranosyloxy)-3,6,8-trimethoxynaphthalene (IBR-3) was characterized. ThnA utilized five molecules of malonyl-CoA as a starter substrate to generate the polyketide 1,3,6,8-tetrahydroxynaphthalene, which could spontaneously be oxidized to the red flaviolin compound 2,5,7-trihydroxy-1,4-naphthoquinone. The amino acid sequence alignment of ThnA revealed similarities with a previously identified type III PKS and identified Cys¹³⁸, Phe¹⁸⁸, His²⁷⁰, and Asn³⁰³ as four highly conserved active site amino acid residues, as found in other known polyketide synthases. In this study, we report the heterologous expression of the type III polyketide synthase thnA in S. lividans TK24 and the identification of THN production in a mutant strain. We also compared the transcription level of thnA in S. lividans TK24 and S. lividans pIBR25-thnA and found that thnA was only transcribed in the mutant.

• 한국대기환경학회지
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• 제29권5호
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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).

• 한국대기환경학회지
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• 제28권3호
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• pp.306-315
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• 2012

In this study, storage stability of reduced sulfur compounds ($H_2S$, $CH_3SH$, DMS, $CS_2$, and DMDS) and $SO_2$ in sampling bags was investigated in terms of two contrasting storage approaches between forward (F) and reverse (R) direction. The samples for the F method were prepared at the same time and analyzed sequentially through time. In contrast, those of reverse (R) method were prepared sequentially in advance and analyzed all at once upon the preparation of the last sample. In addition, relative performance between two different bag materials (PVF and PEA) was also assessed by using 100 ppb standard. The response factors (RF) of gaseous RSC samples were determined by gas chromatography/pulsed flame photometric detector (GC/PFPD) combined with air server (AS)/thermal desorber (TD) system at storage intervals of 0, 1, and 3 days. There is no statistical difference in all RSCs between two storage methods. However, the results of relative recovery indicated 2.58~12.8% differences in compound type between the two storage methods. Moreover, loss rates and storage stability of $H_2S$ and $SO_2$ were considerably affected by bag materials than any other variables. Therefore, some considerations about storage methods (or bag material types) for sulfur compounds are needed if stored by sampling bag method.