• 한국대기환경학회지
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• 제15권2호
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• pp.121-138
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• 1999

This study was carried out to evaluate the performance of a sampling and analytical methodology for the measurement of selected volatile organic compounds (VOCs) in the ambient air. VOCs were determined by the adsorbent tube sampling and automatic thermal desorption coupled with GC/FID and GC/MSD analysis. Target analytes were aromatic VOCs, including BTEX, 1,3,5-and 1,2,4,-trimethylbenzenes(TMBs), and naphthalene. The methodology was investigatedwith a wide range of performance criteria such as repeatability, linearity, lower detection limits, collection efficiency, thermal conditioning, breakthrough volume and calibration methods using internal and external standards. standards. Stability of samples collected on adsorbent tubes during storage was also investigated. In addition, the sampling and analytical method developed during this study was applied to real samples duplicately collected in various indoor and outdoor environments. Precisions for the duplicate samples and distributed volume samples appeared to be well comparable with the performance criteria recommended by USEPA TO-17. The audit accuracy was estimated by inter-lab comparison of both duplicate samples and standard materials between the two independent labs. The overall precision and accuracy of the method were estimated to be within 30% for major aromatic VOCs such as BTEX. This study demonstrated that the adsorbent sampling and thermal desorption method can be reliably applied for the measurement of BTEX in ppb levels frequently occurred in common indoor and ambient environments.

• 한국시뮬레이션학회논문지
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• 제9권2호
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• pp.75-87
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• 2000

In this paper, nonstationary multiple sampling plans are discussed which are difficult to solve by analytical method when there exists dependency between the sample data. The initial solution is found by the sequential sampling plan using the sequential probability ration test. The number of acceptance and rejection in each step of the multiple sampling plan are found by grouping the sequential sampling plan's solution initially. The optimal multiple sampling plans are found by simulation. Four search methods are developed U and the optimum sampling plans satisfying the Type I and Type ll error probabilities. The performance of the sampling plans is measured and their algorithms are also shown. To consider the nonstationary property of the dependent sampling plan, simulation method is used for finding the lot rejection and acceptance probability function. As a numerical example Markov chain model is inspected. Effects of the dependency factor and search methods are compared to analyze the sampling results by changing their parameters.

• 한국환경과학회지
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• 제6권1호
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• pp.33-44
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• 1997

In investigating heavy metal contents at specific areas, the method of selecting sampling points is Important A general method is, according to the law , random sampling of zigzag-form in the selected field. In this work, we studied whether the measured values obtained from a certain method of selecting sampling points is a representative of heavy metal contents in the selected field or not. The selected field for this study is located on the lower Yangsan-river: Gasan-li, Mulgum-myon, Yangsan-gun, KyoungNam, 1 km away from the mi, h stream of Nakdong river. The heavy metals investigated were Cd, Cr, Cu, Fe, Mn, Ni, Pb, and Zn. The inductively coupled plasma(ICPI atomic emission spectrometer was used to measure these metals quantitatively. The number of total sampling points were 24. We compared the total mean values with the mean obtained from various methods of selecting sampling points.

• 자원환경지질
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• 제37권1호
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• pp.49-59
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• 2004

The concectration and distribution of contaminants obtained from a contaminated land investigation or an environmental geochemistry survey constitutes the basis of a decision-making process on environmental policies or of scientific researches. As the quality of data determines the reliability of the result, the investigation plan should be adjusted according to the purpose of the investigation. In general, the effort to improve the data quality had been focused mainly on the QA/QC procedures in laboratories. The rapid progress of analytical instrument has also contributed toward improving the analytical precision to a sacrificable degree. Nevertheless, in many cases, it is not the analytical precision that needs improvement for the better precision of overall measurement process: it is rather during the sampling process in the field that is responsible for the poor precision. To assess the data quality on a measured value, ISO recommends to provide information on "measurement uncertainty" along with the measured value. The measurement uncertainty in an environmental measurement context can be explained as the statistical number that expresses the degree of the uncertainty stemming from the sampling and analytical procedures. There is a cost involved in order to improve the precision of sampling and analytical methods so as to decrease the degree of measurement uncertainty. The economical point of compromise in an investigation planning can be achieved when the allowable degree of uncertainty has been set before-hand. The investigation can then be planned accordingly not to exceed the uncertainty limit. Furthermore, if the measurement uncertainty estimated from the preliminary investigation can be separated into sampling and analytical uncertainties, it can be used as a criterion where the resources for the investigation should be allotted cost-effectively to reinforce the weakest link of the whole investigation process. This paper aims to present a method of estimating the level of measurement uncertainty of a measured contamination concentration at a site used as an example and to show how the estimated uncertainty can be applied to serve the particular purpose of an investigation.

• 대한임상검사과학회지
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• 제39권1호
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• pp.25-30
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• 2007

In this study, the two sampling methods for blood glucose measurement were evaluated in order to reduce pre-analytical error. For this purpose, glucose levels of Li-heparinized plasma (LHP) and Na-fluorinated plasma (NFP) in blood collected from healthy volunteers were determined by using routine hexokinase procedures. The percentage range of pre-analytical error was quantitated by comparing LHP glucose values with NFP glucose values according to delaying analytical time (0, 60, and 120 min). LHP glucose values were decreased by 6.6% in 60 min., 17.7% in 120 min, whereas NFP glucose values decreased by 1.1% in 60 min, 2.0% in 120 min. Therefore it may be recommended that the NFP sampling method should be used for routine blood glucose determination in diabetes mellitus diagnosis.

• 한국대기환경학회지
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• 제14권5호
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• pp.507-518
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• 1998

A field comparison study was carried out to quantify differences among various sampling and analytical methods for volatile organic compounds (VOCs) at a site in Vlsan in June 1997. Air sampling containers (SUMMA canisters) were used by the Korea Institute of Science and Technology (KIST) and adsorption tubes (carbotrap) were used by Yeungnam University (YN Univ.) for sampling ambient air. Duplicate samples obtained by KIST were analyzed by KIST with a GC-MS system for aromatics and halogenated hydrocarbons and by Atm AA with a GC -FID system for C2∼C9 hydrocarbons, respectively. The adsorption tube samples were analyzed by YN Univ. with a GC-FID system for aromatics. VOC levels for the duplicate canister sampls analyzed by KIST and Atm AA were in good agreement. Concentrations of aromatics by the adsroption tube method were generally higher than those by the canister sampling method by factor of 1.5 to 2.0. Differences between the two sampling methods were discussed.

• 분석과학
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• 제25권2호
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• pp.91-101
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• 2012

2010년부터 지정악취물질로 관리 중인 유기지방산은 큰 반응성과 그에 따른 낮은 회수율 등의 문제로 인해, 분석이 난해한 성분으로 알려져 있다. 악취공정시험기준에서는 대기 중에 존재하는 유기지방산을 분석하는 방법으로 알칼리함침필터법과 알칼리흡수용액법을 제시하고 있다. 본 연구에서는 유기지방산의 분석기법을 전반적으로 비교검토하였다. 그러나 이들 지정분석방법에 대한 객관적인 검증이 쉽지않다는 점을 감안할 때, 유기지방산의 새로운 대안 분석방안으로 고체흡착관-저온농축탈착법 등을 고려할 필요가 있다. 고체흡착관으로 시료를 채취하고 저온농축열탈착기를 이용하여 분석할 경우, 공정시험기준상에 제시한 분석방법들에 비해 상당히 간편하고 검정이 용이하다는 이점이 있다. 본 연구에서는 이러한 분석방법에 대한 고찰에 덧붙여, 표준시료의 준비, 시료의 채취단계, 최종적인 검출단계에 대한 부분에 대해서도 검토하였다. 유기지방산의 현장시료를 채취 및 분석하기 위해서, 용기채취법의 적용은 심각한 오차를 수반할 수 있다는 점을 확인하였다. 또한 현장에서 채취한 시료의 유기지방산을 분석할 때, GC/FID에 의존할 경우, 여러 가지 간섭 성분의 영향을 배제하기 어렵다. 따라서 유기지방산의 분석에는 GC/MS를 이용하여 정량뿐 아니라 정성적인 부분까지 동시에 검토하는 것이 중요하다.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제7권8호
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• pp.1860-1875
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• 2013

In this paper, we present a comparative performance evaluation of the sampling frequency synchronization method that eliminates the initial sampling frequency offset (SFO) to reduce the overall synchronization time in Digital Radio Mondiale (DRM) receivers. To satisfy the advanced synchronization performance requirements of DRM receivers, we introduce the conventional DRM synchronization method (Method 1) and another method (Method 2), which does not perform the initial sampling frequency synchronization in the conventional synchronization method (both methods are mentioned later in this paper). To demonstrate the effectiveness of the performance evaluation, analytical expressions for frame detection are derived and simulations are provided. Based on the simulations and numerical analysis, our result shows that Method 2, with a negligible performance loss, is robust to the effects of the initial sampling frequency synchronization even if SFO is present in the DRM signal. In addition, we verify that the inter-cell differential correlation used between reference cells is robust to the effect of the initial SFO.

• 분석과학
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• 제37권3호
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• pp.174-188
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• 2024

본 연구에서는 토양 및 지하수 중 미세플라스틱(MP) 분석법 표준화를 위해 관련 국내·외 연구동향을 검토하고 매체 별 시료채취 방법, 전처리 방법 및 분석 장치의 종류 등에 관한 대표적인 방법을 리뷰하였다. 토양 시료채취는 시료채취 지점선정, 채취 깊이 및 시료량을 고려하고 있으며 대부분 15 cm 이내(표토) 깊이에서 약 1 kg의 시료를 혼합채취하는 것으로 파악되었다. 지하수 시료채취는 정치방법과 연속흐름방법 중 연속흐름방식이 대표적이고 채취량 300~1,000 L 구간에서 유량 2~6 L/min로 채취하며 현장 여과하였다. 처리 방법은 두 매체에 공통적으로 유기물 분해와 밀도차 분리로 나뉘며 유기물 분해방법인 H₂O₂, 산, 알칼리, 효소 활용 중 H₂O₂가 추천된다. 밀도 분리는 NaCl, ZnCl₂, ZnBr₂ 등의 시약 중 NaCl이 주로 사용되나 분석하고자 하는 MP의 밀도에 따라 시약을 선택적으로 활용할 수 있다. 분석 기기는 비파괴적 분석법인 FTIR, Raman과 파괴 분석법인 Py-GC/MS가 대표적이다. µ-FTIR은 직경 10 ㎛ 이상 Raman은 1 ㎛ 이상의 MP 재질과 개수 분석이 가능하나 전처리를 통해 유기물과 같은 분광분석의 방해요소를 충분히 제거해야 한다. Py-GC/MS는 복잡한 전처리가 필요 없고 특정 재질의 정량분석이 가능하여 지속적으로 연구되어지고 있다.

• 한국대기환경학회지
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• 제18권5호
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• pp.355-362
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• 2002

There has been relatively a few studies that focused on evaluation of uncertainty for standard methods by which criteria pollutants are analyzed in ambient air. Especially, uncertainty evaluation has not been made yet for sampling and analysis of airborne NO$_2$. Ambient NO$_2$ has been thought to be a major criteria pollutant worldwide because of the potential of ozone formation as well as of its own toxicity. In this study, we tried to assess uncertainties associated with the every step of sampling and of analytical procedure of Griess-Saltzman method. Quality assurance (QA) and quality control (QC) were also emphasized with the uncertainty characterization. The use of Griess-Saltzman method for ambient NO$_2$ analysis showed very uniform daily concentration distribution with the mean of 10.8 ppb and the standard deviation of 1.08ppb during the sampling period. However, seven daily samples collected at the same sampling time and place exhibited highly different concentration distribution. Therefore, we evaluated uncertainties associated with sampling and analysis through the precise application of ISO Guide. Estimates of expanded uncertainties for a total of 62 samples fell in a relatively broad range of 5.17% to 11.85%. On the other hand. the expanded uncertainties were smaller for the high concentration range of greater than 15ppb.