• Mass Spectrometry Letters
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• 제14권4호
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• pp.121-140
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• 2023

It is becoming more and more clear that each cell, even those of the same type, has a unique identity. This sophistication and the diversity of cell types in tissue are what are pushing the necessity for spatially distributed omics at the single-cell (SC) level. Single-cell chemical assessment, which also provides considerable insight into biological, clinical, pharmacodynamic, pathological, and toxicity studies, is crucial to the investigation of cellular omics (genomics, metabolomics, etc.). Mass spectrometry (MS) as a tool to image and profile single cells and subcellular organelles facilitates novel technical expertise for biochemical and biomedical research, such as assessing the intracellular distribution of drugs and the biochemical diversity of cellular populations. It has been illustrated that ambient mass spectrometry (AMS) is a valuable tool for the rapid, straightforward, and simple analysis of cellular and sub-cellular constituents and metabolites in their native state. This short review examines the advances in ambient mass spectrometry (AMS) and ambient mass spectrometry imaging (AMSI) on single-cell analysis that have been authored in recent years. The discussion also touches on typical single-cell AMS assessments and implementations.

• Bulletin of the Korean Chemical Society
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• 제23권3호
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• pp.488-496
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• 2002

SPME techniques have proven to be very useful tools in the analysis of wide VOCs in the air. In this study, we estimated VOCs in ambient and workplace air using a Tedlar ba /SPME/GC/MS system. The calibration curve was set to be linear over the range of 1-30 ppbv. The detection limits ranged from 10 pptv to 0.93 ppbv for all VOCs. Reproducibility of TO-14 target gas mixtures by SPME/GC/MS averaged at 8.8 R.S.D (%). Air toxic VOCs (hazardous air pollutants, HAPs) containing a total of forty halohydrocarbons, aromatics, and haloaro-matic carbons could be analyzed with significant accuracy, detection limit and linearity at low ppbv level. Only reactive VOCs with low molecular weight, such as chloromethane, vinylchloride, ethylchloride and 1,2-dichloro-ethane, yielded relatively poor results using this technique. In ambient air samples, ten VOCs were identified and quantified after external calibration. VOC concentration in ambient and workplace air ranged from 0.04 to 1.85 ppbv. The overall process was successfully applied to identify and quantify VOCs in ambient/workplace air.

• 한국산학기술학회논문지
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• 제21권7호
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• pp.82-89
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• 2020

탄약내의 화약류 특히, 지연제의 지연시간에 대한 온도의 영향은 우리나라와 같이 연평균 최고최저 온도차가 뚜렷한 환경에서 충분히 존재할 수 있음에도 불구하고 이와 관련한 연구는 아직까지 국내에 보고된 바가 없다. 이에 본 연구는 우리나라 탄약류에 주로 사용되는 Zr/Ni계 지연제에 대해 주변 온도에 따른 연소속도 변화를 실험적으로 확인하였다. 이를 위해, K413 수류탄용 K414 신관에 Zr/Ni계 지연제를 충전하고 우리나라 기상환경을 고려한 주변 온도구간(-40 ℃ ~ 50 ℃)에서 온도변화에 따른 K414 신관의 지연시간 변화를 확인 및 분석하였다. K414 신관의 지연시간은 상기 시험 온도구간 내에서 시험온도를 10 ℃ 씩 변화시켜가며 측정하였고, 측정된 지연시간은 Zr/Ni계 지연제 충전 시에 기록한 지연제의 높이를 이용하여 연소속도로 환산되었다. 시험결과, Zr/Ni계 지연제의 지연시간은 주변 온도가 증가함에 따라 선형적으로 감소하는 경향이 있으며, Zr/Ni계 지연제 온도가 1 ℃ 상승할 때 마다 지연시간이 4.18 ms 감소하고, 연소속도는 2.73 mm/ms 로 빨라진 것으로 분석되었다. 즉, 연평균 최고최저 온도차이가 20 ℃ 이상인 주변 온도 환경에서는 약 80 ms 의 지연시간 차이가 발생하므로, Zr/Ni계 지연제의 시험평가 기준수립 시, 지연제가 노출된 주변 온도 조건을 반영한 지연시간이 고려되어야 할 것으로 사료된다.

• 분석과학
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• 제23권1호
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• pp.15-23
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• 2010

본 연구에서 청주지역 대기 중 PFOA 및 PFOS의 오염수준을 조사하기 위해 공단, 주거/상업 및 농촌지역에서 각각 가스상 및 입자상 시료를 채취하였다. 또한 계절적 변화를 조사하기 위해 겨울철, 봄철 및 여름철에 각각 채취하였다. 대기 중 PFOA 및 PFOS의 농도는 각각 불검출~8.02 pg/$m^3$ (평균 2.33 pg/$m^3$)과 1.68~6.94 pg/$m^3$ (평균 3.12 pg/$m^3$)으로 검출되었다. 이들 농도는 외국과 유사하거나 낮은 수준을 보였다.

• 한국대기환경학회지
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• 제26권4호
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• pp.357-366
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• 2010

The purpose of this study is to evaluate a method for the measurement of N,N-Dimethylformamide (DMF) and to apply the method to the ambient air samples. For the determination of DMF together with other general VOCs (e.g., benzene, toluene, and xylenes), adsorption sampling and thermal desorption with GC/MS was used in this study. The sampling and analytical approaches tested in this study showed a good repeatability and linearity with lower detection limits of less than 0.35 ppb. Field measurements were carried out at three industrial sites (Daegu-Seongseo, Siwha and Banwall industrial complexes) and one residential site in Daegu city during a period from October 2006 to November 2008. DMF was detected in 71.8% of the total samples from the Seongseo industrial complex, well known for textile industry. In contrast, DMF was detected in only 20.4% and 12.9% of all the samples from the other two sites in Banwall and Siwha industrial complexes, respectively. This implies that sources of DMF should be strongly associated with textile industry. The mean concentration of DMF also appeared to be the highest in Seongseo site (5.95 ppb), followed by a residential site in Daegu (3.28 ppb), Banwall (0.88 ppb) and Siwha (0.55 ppb). In this study, we demonstrated the environmental significance of DMF in urban ambient air. To our knowledge, the DMF measurement introduced in this paper is the first case of an official report in Korea.

• 한국환경보건학회지
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• 제35권4호
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• pp.322-333
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• 2009

In this study, a measurement method was evaluated for the determination of polycyclic aromatic hydrocarbons (PAHs) in the ambient atmosphere. PAHs were sampled by high-volume samplers, and were then analysed with a GC/MS system. Particulate PAHs were collected on $8"{\times}10"$ quartz fiber filter, while vapor phase PAHs were adsorbed on polyurethane foam (PUF). Target compounds included a total of 36 PAHs, which are known to be frequently detected in the urban atmosphere. It was not necessary to clean-up samples before samples were analyzed using GC/MS, and the overall performance of the method was tested by a variety of quality control and quality assurance schemes. It is generally known that the clean-up procedure can negatively affect the recovery of samples. Precision and accuracy was evaluated using SRM provided by US NIST, and the results were generally satisfactory and reliable. However, the GC/MS method appeared not to be adequate for 6-rings PAHs, such as coronene, due to its lower sensitivity. In addition, collection efficiencies for low molecular compounds, such as 2-rings PAHs, were poor because of the lower retention volume of the PUF adsorbent. As a result, it was concluded that the method based on high-volume sampling and GC/MS analysis can give very reliable data by simultaneous sampling of both particulate and vapor phases for 3-rings to 5-rings PAHs of environmental concern.

• 한국자동차공학회논문집
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• 제10권3호
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• pp.36-43
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• 2002

The characteristics of spray has much effect on performance and emissions for automobile, diesel engine, gas turbine and combustion engines. So spray behavior after impinging the wall is very important for prediction the engine performance. This studies examined about impingement spray considering ambient density(18,24,30kg/ms), temperature(293,473K), impingement angle(0,30,45°). The images of impingement spray were obtained by the high speed video camera. After that we analyzed impingement spray characteristics to use this images. In this experiment, we found that 1) The spray width is reduced by increasing the ambient gas density and temperature,2) The growth of downstream is increased by increasing the impingement angle.

• Mass Spectrometry Letters
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• 제6권3호
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• pp.71-74
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• 2015

Low temperature plasma (LTP) ionization mass spectrometry (MS) is one of the widely used ambient analysis methods which allows soft-ionization and rapid analysis of samples in ambient condition with minimal or no sample preparation. One of the major advantages of LTP MS is selective analysis of low-molecular weight, volatile and low- to medium-polarity analytes in a sample. On the contrary, the selectivity for particular class of compound also implies its limitation in general analysis. One of the critical factors limiting LTP ionization efficiency is poor desorption of analytes with low volatility. In this study, a home-built LTP ionization source with Peltier heating sample stage was constructed to enhance desorption and ionization efficiencies of analytes in a sample and its performance was evaluated using standard mixture containing fatty acid ethyl esters (FAEEs). It was also used to reproduce the previous bacterial identification experiment using pattern-recognition for FAEEs. Our result indicates, however, that the bacterial differentiation from FAEE pattern recognition using LTP ionization MS still has many limitations.

• 한국대기환경학회지
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• 제34권3호
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• pp.393-405
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• 2018

Volatile organic compounds (VOCs) are representative air pollutants due to their detrimental effects on human health and their role in formation of secondary organic aerosols. Assessments and monitoring programs of VOCs using periodic grab sampling like Tedlar bags, canisters, and sorbent traps provide limited information, often with delay times of days or weeks. Selected ion flow tube mass spectrometry (SIFT-MS) is an emerging analytical technique for the real-time quantification of VOCs in air. It relies on chemical ionization of the VOCs molecules in air introduced into helium carrier gas using $H_3O^+$, $NO^+$, and $O_2{^+}$ precursor ions. Real-time monitoring method of 60 VOCs in the ambient air was developed using TO-15 standard gas mixture. Calibration curves, method detection limit, and quantitation reproducibility of the target compounds were tested. Dynamic dilution system was used to dilute standard gas from 0.174 ppbv to 100 ppbv, where calibration curves showed good linearity with $r^2$> 0.95 in all target analytes. Limit of detection (LOD) all compounds were sub ppbv, and some halogenated compounds showed pptv levels. Seven consecutive analyses of target compounds showed good repeatability with relative standard deviation of less than 10%. One day monitoring of VOCs in ambient air was conducted in Geoje. Average concentration of target VOCs in Geoje were relatively lower than other regions, among which formaldehyde showed the highest concentration ($15.4{\pm}5.78ppbv$). SIFT-MS provided good temporal resolution data (1 data per 3.2 minute), which can be used for identifying ephemeral short-term event. It is expected that SIFT-MS will be a versatile monitoring platform for VOCs in ambient air.

• 한국대기환경학회:학술대회논문집
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• 한국대기환경학회 2001년도 추계학술대회 논문집
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• pp.348-349
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• 2001

휘발성유기화합물 (VOCs)은 복잡 다양한 발생원에서 배출되고 있다. 1990년에 개정된 미국 공기청정법 (US Clean Air Act Amendments, CAAA)에서는 총 189개의 화합물을 인간환경에 유해한 유해 대기 오염물질 (HAP, hazordous air pollutants)로 분류하고 있다 (MacKensie, A.R 등, 1991). 이 중 미국 EPA에서는 유해 대기오염물질로서 43개의 VOCs를 정하여, TO-14 화합물로서 일컫고 있다 (허귀석, 1999). (중략)