• The Korean Journal of Pesticide Science
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• v.19 no.1
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• pp.1-4
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• 2015

The current official perfluorochemicals (PFCs) analysis method is established with hydrophilic-lipophilic balance (HLB) solid phase extraction (SPE) clean-up method with LC-tandem mass spectrometry ($MS^n$). Herein the HLB clean-up method from the official method by Korean government was modified with Envi-Carb$^{TM}$ to improve the clean-up efficiency for agricultural water and the unexpected UV disturbance in the water was effectively removed by the adsorbent treatment without a significant disturbance of quantitation. And quadrupole time of flight mass spectrometry (qTOFMS) was suggested to the available $MS^n$ instruments for the residue analysis of PFCs based on the ng/L of quantitation limits in water as well.

• Journal of Korean Society for Atmospheric Environment
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• v.16 no.5
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• pp.477-485
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• 2000

The data set was collected on fifty-eight different days with a 24-h sampling period from October 27, 1995 through August 25, 1996. From the chemical mass balance (CMB) analysis of $PM_{2.5}$ in the Chongju area, the contributions from soil, gasoline, diesel, light and heavy oil combustion were 2.6%, 15.4%, 9.0%, 28.8% and 1.5%, respectively. Residual $NO_{3}^{-}$), residual $SO_{4}^{2-}$ and residual OC, possibly formed in the atmosphere. represented additional 8.0, 10.2, and 1.6% of the $PM_{2.5}$, respectively. Other unidentified sources constituted the remaining 22.9%. From the CMB analysis, the $PM_{2.5}$ source contribution for fall, winter, spring and summer were 92, 76.8, 77.5 and 59.2%, respectively.

• Journal of Korean Society for Atmospheric Environment
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• v.8 no.4
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• pp.229-239
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• 1992

A receptor model application was performed by using a chemical mass balance (CMB) model to identify and apportion the specific source of airborne organic pollutants, particularly polynuclear aromatic hydrocarbons (PAHs). Source profiles of PAHs produced from the combustion of fossil fuels for CMB modeling were prepared by measuring them in emission gases. The emission sources which were examineed for the development of PAH source profiles are a coal-fired furnace using Yontan, a bunker-C iol heating boiler, and gasoline-and diesel engine automobiles. The ambient concentrations of PAHs were determined at four sites in Daejon city in 1991 with a seasonal variation. Wintertime air samples contained more extractable organic matter than summertime samples. The results of CMB modeling were various depending on the sampling sites and seasons, but the emission from bunker-C oil heating boliers was the predominant factor to affect local air quality throughout the year.

• Economic and Environmental Geology
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• v.45 no.5
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• pp.525-533
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• 2012

Snowmelt from seasonal snow covers can be significant in many environments of northern and alpine areas. Water flow and chemical transport resulting from snowmelt have been studied for an understanding of contributions to watersheds or catchments. A Mobile-Immobile water Model (MIM) was developed to describe the movement of ionic tracers through a snowpack by Lee et al. (2008a) and Lee et al. (2008b). To validate the model used in the studies, mass balance calculations of the model were conducted and comparisons were made between model results and analytical solutions in this work. Mass balance was calculated based on the fact that change in total mass within a snowpack with time is equal to sum of any change in the flux of water or ionic tracers into and out of the snowpack. Calculations of both water and ionic mass show almost perfect agreement between changes of two water and solute mass fluxes. Comparisons between model results and analytical solutions including wave velocity and effective saturation show almost perfect agreement.

• Journal of the Korean Wood Science and Technology
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• v.36 no.4
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• pp.102-108
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• 2008

At the University of Maine, a hemicellulose pre-extraction technology is now being investigated to improve pulp yields, reduce the organic and inorganic load for liquor recovery, and create a feed stream for the generation of new biomaterials. It is important to understand the composition of unextracted wood, extracted wood, and pulping extracts in the design of an economically viable pilot-scale ethanol plant. For analysis of wood pulp composition, the total analytical mass balance closure was 100.6, 100.3, and 81.6% for unextracted chips, extracted chips, and pulping extracts from HPLC-H column analysis. Meanwhile, the total analytical mass balance from the HPLC-P column was 97.8, 86.3, and 80.7%, respectively. This slight variability between H- and P-column results for analytical mass balance may be within the experimental error of the measurement. The data generated by this analysis are important to further design work in commercializing this process.

• Journal of Applied Biological Chemistry
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• v.56 no.1
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• pp.53-57
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• 2013

In here, we investigated the quantitative analysis method of indole-3-acetic acid (IAA) and indole-3-butyric acid (IBA) with liquid chromatography-mass/mass spectrometry (LC-MS/MS) or gas chromatography-MS. Two ways of clean-up process were investigated for LC-MS/MS instrumental analysis of IAA, but both a simple dilution and hydrophile-lipophile balance (HLB) solid phase extraction (SPE) were not met the optimal recovery rates for quantitative analysis. On the other hand, the clean-up method for GC-MS was finally optimized through HLB-SPE from 250-folds diluted sample and methylation with trimethylsilyl chloride in methanol for 4 h. The limit of detection for methyl ester of IAA and IBA were both 1.4 mg/L, and recovery rates showed 93-107% from the concentrated liquid fertilizer.

• Proceedings of the Korea Air Pollution Research Association Conference
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• 2004.05a
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• pp.61-62
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• 2004

• Korean Journal of Soil Science and Fertilizer
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• v.49 no.1
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• pp.60-65
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• 2016

The main objective of this research was to estimate the total mass of nitrogen discharged from various sources in paddy field area of South Korea in 2010 and 2013. Input and output budgets for nitrogen were estimated by mass balance approach. The mass balance approach reduces the effect of flow variations, and the large scale approach minimizes local effects, resulting in easier and faster establishment of strategy for nonpoint pollution problems. Nitrogen inputs were chemical fertilizer, compost, atmospheric deposition, biological fixation, and agricultural water, while crop uptake, denitrification, volatilization, and infiltration were nitrogen outputs. The estimated total nitrogen inputs for paddy field in South Korea were $266,211ton\;yr^{-1}$, $260,729ton\;yr^{-1}$, while those of total nitrogen outputs were $168,463ton\;yr^{-1}$, $164,994ton\;yr^{-1}$ in 2010 and 2013, respectively. Annual amounts of potential nitrogen outflow from paddy field were $97,748ton\;yr^{-1}$, $95,735ton\;yr^{-1}$ in 2010 and 2013. Also, annual rate of potential nitrogen outflow were 36.7%, 36.7% in 2010 and 2013, respectively.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.37 no.4 s.112
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• pp.44-51
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• 2005

Paper mills use and discharge lots of water. And so now the papermaking industry could be classified into major water consuming industry In order to analyze the process water network and to establish the mass, water balance of duplex board mill, computer aided simulation was made using water pinch method. Based on the pinch analysis results, reuse of process water, after regenerating by microfilter as much as $140\;m^3/hr$, could be suggested without significant accumulation of contaminants in process water. According to this suggestion about $3000\;m^3/day$ of recycled process water could be sub stituted by regenerated water and consequently $30\%$ of energy cost is expected to be reduced.

• Journal of Korean Society for Atmospheric Environment
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• v.25 no.3
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• pp.219-236
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• 2009

Particle-phase organic tracers (molecular markers) have been shown to be an effective method to assess and quantify the impact of sources of carbonaceous aerosols. These molecular markers have been used in chemical mass balance (CMB) models to apportion primary sources of organic aerosols in regions where the major organic aerosol source categories have been identified. As in the case of all CMB models, all important sources of the tracer compounds must be included in a Molecular Marker CMB (MM-CMB) model or the MMCMB model can be subject to biases. To this end, the application of the MM-CMB models to locations where reasonably accurate emissions inventory of organic aerosols are not available, should be performed with extreme caution. Of great concern is the potential presence of industrial point sources that emit carbonaceous aerosols and have not been well characterized or inventoried. The current study demonstrates that emissions from industrial point sources in the St. Louis, Missouri area can greatly bias molecular marker CMB models if their emissions are not correctly addressed. At a sampling site in the greater St. Louis Area, carbonaceous aerosols from industrial point sources were found to be important source of carbonaceous aerosols during specific time periods in addition to common urban sources (i.e. mobile sources, wood burning, and road dust). Since source profiles for these industrial sources have not been properly characterized, method to identify time periods when point sources are impacting a sampling site, needs to avoid obtaining biases source apportionment results. The use of real time air pollution measurements, along with molecular marker measurements, as a screening tool to identify when point sources are impacting a receptor site is presented.