• Analytical Science and Technology
• /
• v.27 no.6
• /
• pp.269-276
• /
• 2014

A short study for the uncertainty of post column isotope dilution method has been performed for the analysis of Selenomethionine in HPLC-ICP/MS. Major error sources studied were concentration and the flow rate of Se isotope solution, atomic weights of Se in spike and sample, and isotope ratio measured for the spiked sample. Uncertainties were obtained for each factor and the contribution for the total concentration uncertainty was 54.4% and 0.61%, 0.0072% and 0.018%, and 45.0%, respectively. The biggest contribution factor was concentration of the spike solution and the second was the isotopic ratio measured for the spiked sample solution. The mass flow rate of spike and atomic weights did not show much contribution. The calculated total uncertainty was $1.46ng{\cdot}g^{-1}$ for the standard SeMet ($126.30ng{\cdot}g^{-1}$). The experimental result was $127.09{\pm}1.46ng{\cdot}g^{-1}$ and the relative uncertainty was 1.20%.

• Journal of Soil and Groundwater Environment
• /
• v.10 no.3
• /
• pp.9-15
• /
• 2005

Soil aquifer treatment is a water reuse technology that secondary or tertiary treated wastewater is infiltrated into the aquifer in which physical and biochemical reactions occur. Major consideration in SAT is the removal and transport of DOC and nitrogen species. In this study, reaction mechanism in SAT was examined considering nitrification, denitrification and organic oxidation. In addition, SAT modeling system was developed as the reaction mechanism was applied to groundwater flow and transport model. In verification of the reaction module by 1-dimensional unsaturated soil column test, the experimental data of all of the species, ammonium, nitrate, DOC and DO, were well matched with the simulation results. In sensitivity analysis, ammonium partition coefficient, dissolved oxygen inhibition constant and biomass decay rate affect ammonium, DOC and DO concentration of effluent, respectively.

• Clean Technology
• /
• v.13 no.3
• /
• pp.222-227
• /
• 2007

The photocatalytic degradation of livestock wastewater has been investigated over $TiO_2$ photocatalysts irradiated with a ultraviolet (UV) light. The effect of operational parameters, i.e., distance, reaction area, concentration of suspended solids(SS), and column diameter on the degradation of livestock wastewater has been performed in lab-scale. The optimal conditions for livestock wastewater were determined: distance was 3 cm (less than 7 cm), reaction area was $3.6\;m^2$, SS concentration was 40 mg/L (less than 300 mg/L) and column diameter was 5 mm (less than 10 mm). Under the optimal conditions, COD, color and coliform removal efficiencies were approximately 49%, 53% and 100%, respectively. Non-biodegradable COD removal efficiency increased with 57% using by photocatalysis process. Therefore, it is shown that photocatalysis has an effect on degradation of non-biodegradable organic matter.

• Journal of the Korean Chemical Society
• /
• v.53 no.2
• /
• pp.137-143
• /
• 2009

Liquid chromatographic enantiomer separation of N-tert-butoxycarbonyl (BOC) $\alpha$-amino acids and their ethyl esters was performed on covalently immobilized chiral column (Chiralpak IC) derived from polysaccharide derivative. The solvent versatility of the covalently immobilized Chiralpak IC in enantiomer separation of N-BOC $\alpha$-amino acid ethyl ester derivatives was shown and the chromatographic parameters of their enantioselectivities and resolution factors were greatly influenced by the nature of the mobile phase. Also the effect on the dissolving solvent for these analytes on the enantiomer separation using the same mobile phase and the examples of preparative enantiomer separation on analytical column were shown.

• Korean Chemical Engineering Research
• /
• v.46 no.5
• /
• pp.971-976
• /
• 2008

Water pollution by ammonium ion and nitrate is a common and growing problem in the ecosystem. Process of biological removal consists of nitrification and denitrification by bacteria. Ammonium is oxidized generally to nitrate by nitrification and nitrate is reduced to dinitrogen gas in the subsequent denitrification process. Although natural zeolite is well known for its ability to preferentially remove ammonium, it is not sufficiently removing ammonium ion and nitrate by adsorption. In order to overcome this problem, a method of biological removal with zeolite is used for simultaneous removal of ammonium and nitrate. As a result, in case of shaking culture with 1% seed and passing through zeolite column, the process revealed that ammonium ion could be removed completely after 14 hours. The removal of nitrate using columns with naturally adsorbed bacteria onto zeolite reached approximately 100% after 4 hours.

• Analytical Science and Technology
• /
• v.20 no.2
• /
• pp.109-114
• /
• 2007

In this study, soxhlet extraction and dissolution-precipitation method are used for separating analyte from polymer materials. In soxhlet extraction efficiency test, it has been found that the DCM, Toluene, THF, and mixtures Acetone/Hexane (1:4, v/v) gave good extraction efficiency, while the use of the ethyl ether, acetone/ethyl ether (1:4, v/v), acetone/hexane (1:1, v/v), DCM/hexane (1:1, v/v) resulted in significantly lower values. In case of dissolution-precipitation method, there is no considerable difference with used different dissolving solvent. The elution amount of multi layer silica and Florisil column were determined with hexane 250 mL and 70 mL of hexane, respectively. Range of PBDE in real waste plastics was N.D.~1,028 ppm.

• Analytical Science and Technology
• /
• v.7 no.1
• /
• pp.33-39
• /
• 1994

The purpose on this study was to develop a new improved chromatographic method for determination of trace phenols from environmental waste water. The research was carried out with selected 8 phenols, and solid-phase extraction was employed as sample pretreatment method. The coupling of XAD-4 and Dowex $1{\times}8$ resin as preconcentration column increased the selectivities toward interferences coexisted in matrix. Automation was accomplished with on-line process of pretreatment and HPLC system. After elution of sample through XAD-4 column, phenols were adsorbed by dispersion force, then displaced from it by ACN basified, simultaneously and selectively readsorbed via anion exchange on Dowex $1{\times}8$. Dowex $1{\times}8$ column was washed by water. Phenols readsorbed were removed from Dowex $1{\times}8$ column by a minimum volumn of methanol containing HCl. Each pretreatment step was connected by switching valves and the eluate was directly on-line injected to obtain fast and reliable results into the HPLC. Recovery of phenols was greater than 90%. To examine utility of this method, analysis of phenols from laboratory waste water sample which was added some organic pollutants to find with phenols on environmental waste water were also accomplished without their interference effects.

• KSBB Journal
• /
• v.11 no.5
• /
• pp.606-612
• /
• 1996

A specific ammino auid in a mixture can be crystallized inside an ion exchange column when displacer concentration is high enough to concentrate the amino acid in a pure band beyond its solubility limit. Glutamic acid formpd a discrete crystal layer in a cation exchanger column by operating displacement development mode and using a high concentration of displacer NaOH. The glutamic acid crystal formed was eluded from the column with the effluent stream and collected in a fraction collector. When 1.0 M of NaOH was used as a displacer, more than 60% of the loaded glutamic acid was recovered as crystal. The continuous crystallization and dissolution of crystal occurred, resulting in apparent movement of the crystal along the column without clogging or pressure increase. NaOH was proved a better displacer than NaCl because hydroxide ions neutralized hydrogen ions released from the resin and thus reduced the number of hydrogen ion competing with sodium ion for re-adsorption. The displacement development process coupled with crystallization provided higher concentration and recovery of glutamic acrid than conventional chromatography.

• The Korean Journal of Pesticide Science
• /
• v.9 no.4
• /
• pp.330-337
• /
• 2005

This study was investigated to elucidate the pesticide mobility in three different soil textures(Heongseong sandy loam; Chuncheon, loam; Taeback, silty clay loam) and four different gravel contents(0, 20, 40, 60%) of Taebaek soil using soil column. Carbofuran, which ranks the highest water solubility among 7 pesticides(carbendazim, carbofuran, chlorpyrifos, cypermethrin, dimethomorph, diniconazole and endosulfan) was defected over 87% in leachate samples within all soil types from early sampling time. Amount of 5 residual pesticides excluding carbendazim and carbofuran were ordered silty clay loam > loam > sandy loam, indicating pesticide residues are related to percentage of clay contents in soils. Comparing the amount of residual pesticides in soil column(upper, middle and lower layer), 6 pesticides apart from carbofuran were found in the range of $50{\sim}92%$ on the upper layer of silty clay loam and loam. Mobility of pesticides either in soil or leachate samples is dependant on water solubility of pesticide and clay content of soil. The results obtained from four different gravel contents of Tacback soil were similar to the results of three different soil textures. Also it was found that more the gravel contents, faster the flow velocity of leachate water. These results possibly provide an idea to select proper pesticides and to reduce soil and water contamination at alpine and sloped-land.

• The Korean Journal of Pesticide Science
• /
• v.9 no.4
• /
• pp.292-302
• /
• 2005

Condition of Ion-Trap gas chromatography-mass spectrometry (GC-MS) for rapid screening of 206-pesticides residues in agricultural foodstuffs was optimized. As applying a wide-bore column (10 m${\times}$0.53 mm, DF 0.25 um) connected with a fused silica restrictor (0.6 m${\times}$0.1 mm), a significant retention time reduction was obtained. Additionally, the shape of peaks was sharper and higher than classical GC's and GC-MS's, which allowed lower detection limits. To easily manage many spectral data, both of Electron Ionization(EI) and Chemical Ionization(CI) techniques were adopted in screening procedure. At the following steps, MS-MS technique were used to confirm screened analytes in complicated matrices.