• Proceedings of the Korea Air Pollution Research Association Conference
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• 2000.11a
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• pp.265-267
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• 2000

The objective of this study is to analyze, design and evaluate a new gas cleanup or sampling system that will remove erosive, corrosive, and fouling contaminants present in an effluent stream as either solid or liquid particles providing a clean gas stream. The gas clean-up or sampling system considered in this study is an irrigated, rotating element device. The device consists of a central disk-like hub from which emanate radially wires or cylindrical elements. (omitted)

• Journal of Korean Society of Environmental Engineers
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• v.32 no.5
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• pp.455-460
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• 2010

This study was carried out to find out any inherent problems occurring in the sampling and analytical procedures, and to suggest the relevant solutions to the problems. In addition, an optimal condition of clean-up process was developed, which was based on a method using silica glass column. As a result of experiments to test any artificial contamination of blank samples such as glassware and collection media, artifacts of DBP and DEHP appeared to be detected in various kinds of laboratory tools and apparatuses used in the sampling and analytical works. Therefore, it is necessary to investigate a degree of contamination before laboratory works by conducting a prior check any possible contaminations in all experimental tools and apparatus. It is also necessary to devise a method to avoid a tool, if possible, or to use a substitute of phthalate free. If the use of any plastic tool to cause contamination is inevitable, it should be properly corrected with a blank level, as is equally treated as the sample. The clean-up process demonstrated in this study can give us a significant benefit in terms of the quantity and quality of a target compound by GC/MS analysis.

• Food Science of Animal Resources
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• v.21 no.2
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• pp.149-155
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• 2001

The aims of this study were to examine contamination sources and provide the basic data in establishment of sanitary standard for raw pork meat. From \"Random sampling(I)\", initial total plate counts of post-slaughter samples for the group A, B and C were 1.5${\times}10^4$cfu/$textrm{cm}^2$, 5.5${\times}10^5$cfu/$textrm{cm}^2$ and 1.8${\times}10^4$cfu/$textrm{cm}^2$, respectively, and of post-prechilling samples for the group A, B and C were 1.0${\times}10^4$cfu/$textrm{cm}^2$, 4.6${\times}10^5$cfu/$textrm{cm}^2$ and 2.5${\times}10^4$cfu/$textrm{cm}^2$, respectively. Initial total plate counts of post-transportation samples for the group D, E and F did not increased, as did the group A, B and C. From \"Normal sampling(II)\", initial total plate counts of post-slaughter, post-prechilling, post-transportation and post-2 days preservation samples were 7.3${\times}10^4$cfu/$textrm{cm}^2$, 9.6${\times}10^4$cfu/$textrm{cm}^2$, 2.0${\times}10^5$cfu/$textrm{cm}^2$ and 2.5${\times}10^5$cfu/$textrm{cm}^2$, respectively. From \"Clean sampling(III)\", initial total plate counts of post-slaughter, post-prechilling, post-transportation and post-2 days preservation samples were decreased to 7.0${\times}10^2$cfu/$textrm{cm}^2$, 7.5${\times}10^2$cfu/$textrm{cm}^2$, 8.5${\times}10^2$cfu/$textrm{cm}^2$ and 5.5${\times}10^3$cfu/$textrm{cm}^2$, respectively, compared with "Normal sampling(II)". No E. coli O157:H7, Staphylococcus aureus and Salmonella were detected at each sampling step. Consequently, a slaughter method like "Clean sampling(III)" showed a better sanitary effect to low total plate counts of 10$^2$∼10$^3$times, compared with "Normal sampling(II)". The one of contamination sources for raw pork meat was at a slaughtering step, and "Clean sampling" method may be considered as the one of sanitary standards.

• Particle and aerosol research
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• v.13 no.4
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• pp.165-172
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• 2017

For precise particle measurements in combustion environments, various dilution sampling methods were compared. Dilution equipments using dilution tunnels and hot/cold dilution with porous tube dilutors were most frequently used so far. The combination of porous tube dilutor and ejector diluter has relatively small footprint, and it results in lower particle losses compared to other methods. To determine the portion of condensable particulate matter, proper temperature control and flow control is required.

• Journal of Korean Society for Atmospheric Environment
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• v.14 no.1
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• pp.43-62
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• 1998

This study was carried out to investigate the influence of different sampling methods on the measured concentrations of polycyclic aromatic hydrocarbons (PAH) both in the vapor and particulate phases, and to evaluate the effects of ambient temperature and sampling duration on the losses of PAH associated with particle samples due to volatilization. The experimental protocol of this study is consisted of two parts. The first part is related to the comparison of PAH concentrations measured by 4 different sampling systems, each of which involves different sampling principles for comparison purposes, including a medium-volume sampler with XAD-2 adsorbent, a high-volume sampler with polyurethane foam (PUF), two identical low-volume samplers: one with XAD-2 and the other with PUF, respectively. The second part of this study is to quantitatively estimate the losses of particulate PAH samples by volatilization during sampling, using two identical low-volume samplers: one was used for changing the filters every 3 hrs, 6 hrs, 12 hrs, and 24 hrs sampling, while the other was maintained for continuous 48 hours sampling without changing the filter. The concentrations of volatile PAH including 2-3 rings appeared to be significantly affected by the type of adsorbent. Measured levels of these lower-molecular weight PAH by XAD-2 adsorbent were much higher than those by PUF for both high-volume and low-volume sampling. PUF was found to give rise to unknown components that interfered with the PAH analysis, even after extensive clean-up. In addition, the retention efficiency of PUF for lower molecular weight PAH was subject to a large variation, being significantly influenced by sampling conditions such as ambient temperature. However, the effect of sampling methods with different adsorbents on the measured levels of semi-volatile compounds including 4 rings PAH such as fluoranthene, pyrene, BaA and chrysene, was not so much significant as more volatile PAH compounds. It was also clear from this study that volatilization losses of the semi-volatile PAH collected on the filters were inevitably occurred during prolonged sampling, and hence the results obtained from conventional sampling methods may not be expected to yield an accurate distribution of PAH between the vapor and particulate phases.

• Journal of Korean Society for Atmospheric Environment
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• v.34 no.1
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• pp.120-143
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• 2018

The analytical methods and their ambient levels of organic nitrogenous compounds such as nitrosamines, nitramines (nitroamines), imines, amides and nitro-polycyclic aromatic hydrocarbons (nitro-PAHs) in the atmosphere are summarized and discussed. Sampling for the analysis of organic nitrogenous compounds was mostly conducted using high volume air sampler. The direct liquid extraction (DLE) using sonification and the pressurized liquid extraction (PLE) using the accelerated solvent extraction (ASE) have been frequently employed for the extraction of organic nitrogenous compounds in the atmospheric samples. After extraction, clean-up via filtration and the solid phase extraction (SPE) and concentrations using nitrogen and rotary evaporator have been generally conducted but in some studies the clean-up and concentration steps have been omitted to prevent the loss of analyte and improve the recovery rate of the analytical procedure. Instrumental analysis was mainly carried out using gas chromatography (GC) or the high performance liquid chromatography (HPLC) coupled with the single quadrupole mass spectrometer or tandem mass spectrometer in the electron ionization (EI), positive chemical ionization (PCI) and negative chemical ionization (NCI) mode and analysis sensitivity of nitrosamines and nitramines were higher in NCI mode. Desirable sampling and analysis methods for analyzing particulate organic nitrogenous compounds are suggested.

• Safety and Health at Work
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• v.10 no.3
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• pp.389-392
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• 2019

When conducting an exposure assessment, the primary goal of the industrial hygienist is to fully characterize the worker's exposure during a work shift to compare it with an occupational exposure limit. This applies regardless of the duration of the work activity as an activity that is relatively short in duration can still present exposure in excess of the occupational exposure limit even when normalized over an 8-hr shift. This goal, however, is often impeded by the specification of a minimum sample volume in the published sampling method, which may prevent the sample from being collected or submitted for analysis. Removing the specification of minimum sample volume (or adjusting it from a requirement to a recommendation), in contrast, allows for a broader assessment of jobs that consist of short-duration and high-exposure activities and also eliminates the unnecessary practice of running sampling pumps in clean air to collect a specified, minimum volume.

• Proceedings of the Korean Geotechical Society Conference
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• 2002.10a
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• pp.577-584
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• 2002

We have employed two methods to remove slime at the end of the sampler in clay layers. The first method is a sampling process that harnesses low pressure to clean up the ground around the sampler tip. The second method, in consideration of a disturbed layer, involves a technique of inserting the sampler 50 cm deep into the ground before cleaning up the verge of the sampler by using high pressure. Physical and mechanical properties of these two methods have been compared and analyzed to investigate how different sampling methods affect degree of disturbance. The first method shows little disturbance since the unconfined compression test results in quite greater E$\_$50//q$\_$u/ in the first method than in the second method. On the other hand, the consolidation test results in a slightly greater compression index in the second method than in the first method, when their indexes are compared in the same depth. This suggests that the second method demonstrates less disturbance than the first method does. It is assumed that the second method may reduce disturbance slightly, However, we suspect that choosing any of the two methods would not obtain a considerable difference in sampling.

• Journal of Environmental Health Sciences
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• v.35 no.4
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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.

• Journal of Korean Society for Atmospheric Environment
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• v.7 no.1
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• pp.1-16
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• 1991

In this study, sampling and analytical procedures were evaluated for the determination of ambient levels of atmospheric PAH, both in gaseous and particulate phase. The method involves low-volume sampling and Soxhlet extraction of the filters and Tenax absorbent, followed by a clean-up stage using a silica column prior to analysis by reversed-phase HPLC with wavelength programmable fluorescence and UV detection. A total of 18 PAH were identified and quantified, all of which have been of environmental concern. In order to validate the methodology and to ensure compatibility of the results, the analytical method used for the determination of PAH was evaluated with respect to the efficiencies of extraction and clean-up procedure, HPLC separation, and lower limits of detection. In addition, substrate dependency of PAH recovery was investigated for the two types of fiters, i.e. glass fiber and PTFE filters.