• Analytical Science and Technology
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• v.10 no.4
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• pp.282-290
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• 1997

The sorption and desorption properties of U(VI), Th(IV), Zr(IV), Cu(II), Pb(II), Ni(II), Zn(II), Cd(II) and Mn(II) ions on XAD-16-[4-(2-thiazolylazo)orcinol] (TAO) chelating resin were studied by elution method. The effect was examined with respect to overall capacity of each metal ion, separation of mixed metal ions, flow rate and concentration of buffer solution for optimum condition of sorption. The overall capacities of some metal ions on this chelating resin were 0.35nmol U(VI)/g resin, 0.49nmol Th(IV)/g resin, 0.41nmol Cu(II)/g resin, and 0.31nmol Zr(IV)/g resin, respectively. The elution order of metal ions obtained from breakthrough capacity and overall capacity at pH 5.0 was Th(IV)>Cu(II)>U(VI)>Zr(IV)>Pb(II)>Ni(II)>Zn(II)>Mn(II)>Cd(II). The group separation of mixed metal ions was possible by increasing pH in pH range 2~5 at a flow rate of 0.28mL/min. Characteristics of desorption were investigated with desorption agents such as $HNO_3$, HCl, $HClO_4$, $H_2SO_4$, and $Na_2CO_3$. It was found that 2M $HNO_3$ showed high desorption efficiency to most of metal ions except Zr(IV) ion. Also, desorption and recovery of Zr(IV) ion were successfully performed with 1M $H_2SO_4$. Recovery of trace amount of U(VI) ion from artificial sea water was over 94%. The chelating resin, XAD-16-TAO was successfully applied to group separation of rare earth metal ions from U(VI) by using 2M $HNO_3$ as an eluent.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.26 no.3
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• pp.307-316
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• 2016

Objectives: In general, NIOSH method 5506 is most widely used for the occupational exposure measurement of PAHs, but 2-4 ring PAHs have poor desorption efficiency, especially for a filter. The purpose of this study was to determine a method to increase the desorption efficiency of 16-PAHs using an ultrasonic extraction procedure. Methods: Test samples prepared spiked XAD-2 tubes and PTFE filters in the range of $0.01-1.0{\mu}g/mL$ for desorption efficiency study. Four different extraction solvents, acetonitrile, acetone, tetrahydrofuran and dichloromethane, were tested in order to select the most suitable solvent for the extraction of the 16 PAHs. The addition of dimethyl sulfoxide and sonication time were considered in order to determine the method with the highest extraction efficiency. All samples were made in three sets and analysis was replicated seven times by HPLC. Results: Acetonitrile and acetone were the optimized as an extraction solvent and desorption efficiency of 2-ring PAHs such as naphthalene, acenaphthylene were increased 3~19% with dimethyl sulfoxide for XAD-2. Acetone was the best extraction solvent for PTFE filter and the desorption efficiency was increased 3~13% for 2- to 4-ring PAHs. The optimum sonication time was 60 minutes and desorption efficiency increased with extraction time. Conclusions: As a result, the best extraction solvent was acetone with dimethyl sulfoxide for ultrasonic extraction procedure and the desorption efficiency of this method was better than NIOSH 5506's. This study could be applied as a method for occupational exposure measurement of PAHs.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.19 no.4
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• pp.403-411
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• 2009

This study was performed to propose appropriate conditions suited to the analysis of naphthalene by comparing desorption efficiencies under various conditions. 1. As to influence by adsorbing media and desorbing solvent on desorption efficiency of naphthalene, when adsorbed by CCT, o-xylene gave the highest desorption efficiency of $73.96{\pm}0.53%$ while the lowest of $1.14{\pm}0.03%$ desorbed by ether. Both XAD-2 and Chromosorb 106 showed around 90% of desorption efficiencies for each solvent, especially desorption efficiencies more than 95% were achieved when adsorbed by Chromosorb 106 and desorbed by $CS_2$ or o-xylene. 2. Desorption efficiencies descended over the storage period in any condition(p<0.05). For all three adsorbing media, while desorption efficiencies showed no significant difference(p>0.05) between room temperature and refrigeration a day of loading, samples kept in room temperature had higher desorption efficiencies than refrigerated ones in 7 and 14 days with significant difference(p<0.05).Also, desorption efficiencies dropped drastically in 7 days, from that point the decreasing tendency went mild. 3. When respective 1 TLV and 0.1 TLV of naphthalene were spiked on CCT and desorbed by CS2($46.45{\pm}0.59%$ vs. $30.15{\pm}0.81%$), o-xylene($73.96{\pm}0.53%$ vs. $67.51{\pm}1.34%$), and ether($1.14{\pm}0.03%$ vs. N.D.) desorption efficiencies increased as the amount of loading increased(p<0.05).On the other hand, naphthalene spiked on XAD-2 and Chromosorb 106 indicated no significant difference(p>0.05) in desorption efficiencies between 1 TLV and 0.1 TLV. In conclusion, in order for favorable desorption efficiencies of naphthalene it is important to select appropriate adsorbing media and desorbing solvent accordingly. The result revealed that adsorbing media of XAD-2 and Chromosorb 106 outperformed CCT and desorbing solvents of $CS_2$ and o-xylene achieved over 90% of desorption efficiencies when adsorbed on XAD-2 and Chromosorb 106. Also, considering the tendency that desorption efficiencies of naphthalene decrease with time, the samples should be analyzed as soon as possible.

• 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 the Korean Society of Food Science and Nutrition
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• v.38 no.3
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• pp.391-395
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• 2009

To materialize anti-inflammatory compounds from dandelion leaves, we studied optimal conditions of hot water extraction and concentration. We investigated the properties of extracts on various temperatures between 60 and $90^{\circ}C$. Extraction yields at $60^{\circ}C$ were the highest at $39.2{\pm}1.3%$ and flavonoid contents were increased by heating. However, anti-inflammatory activities were remarkably decreased by increasing temperature. According to the results that the highest anti-inflammatory activities of water extract were demonstrated at $60^{\circ}C$, cell wall degrading enzyme treatment was carried out to increase extraction yield of anti-inflammatory compounds. The enzyme treatment resulted in increased yields and flavonoids from dandelion leaves of 1.5-fold and anti-inflammatory activities were not decreased. Also, column chromatography was used for concentration of anti-inflammatory compounds from extract of dandelion leaves treated with enzyme. Anti-inflammatory activities of adsorbed compounds on Amberlite XAD-2 and Sepabeads SP-850 were significantly increased. However, yields of adsorbed compounds were increased over two-folds on Sepabeads SP-850 compared to Amberlite XAD-2. Thus Sepabeads SP-850 was more effective than Amberlite XAD-2 to concentrate the anti-inflammatory compounds of dandelion leaves.

• Bulletin of the Korean Chemical Society
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• v.27 no.9
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• pp.1293-1296
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• 2006

In this study, a solid phase extraction method has been developed for the preconcentration and separation of the elements Cr(III), Fe(III), Co(II) and Pb(II) at trace levels by using a column packed with Amberlite XAD-1180 resin loaded with 4-(2-pyridylazo)-resorcinol (PAR) reagent. After preconcentrating, the metals retained on the column were eluted with 20 mL of 3 mol/L $HNO_3$ and then determined by flame atomic absorption spectrometry (FAAS). The factors affecting the recovery of the elements, such as pH, type and concentration of eluent, volume of sample and elution solution, and matrix components, were also ascertained. The recoveries of Cr(III), Fe(III), Co(II) and Pb(II) were found to be $99\;{\pm}\;4,\;97\;{\pm}\;3,\;95\;{\pm}\;3$ and $98\;{\pm}\;4$%, respectively, under the optimum conditions at 95% confidence level and the relative standard deviations found by analyzing of nine replicates were $\leq4.4$%. The preconcentration factors for Cr(III), Fe(III), Co(II) and Pb(II) were found as 75, 125, 50 and 75 respectively. The detection limits (DL, 3s/b) were 3.0 $\mu g/L$ for Cr(III), 1.25 $\mu g/L$ for Fe(III), 3.3 $\mu g/L$ for Co(II), and 7.2 $\mu g/L$ for Pb(II). The recoveries achieved by adding of metals at known concentrations to samples and the analysis results of Buffalo river sediment (RM 8704) show that the described method has a good accuracy. The proposed method was applied to tap water, stream water, salt and street dust samples.

• Journal of the Korean Chemical Society
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• v.37 no.5
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• pp.513-522
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• 1993

The purpose of this study is to optimize the selectivity of mobile phase solvents for separation of 25 phenols in reversed phase liquid chromatography and to accomplish the simultaneous preconcentration and separation of trace phenols from water samples. Phenols used in this study were classified into three groups, chloro-, methyl-, and nitrophenols. Quaternary solvent mobile phases were employed to improve the selectivity. Overlapping resolution maps(ORM) as a statistical simplex techniques was used to predict the optimum solvent system. Additional criterion such as pH and temperature were also investigated. In order to improve the resolution and decrease the analysis time, isoselective multisolvent gradient elution system was employed with ORM-Prism method. The simultaneous preconcentration and separation of trace phenols from water samples were performed by using XAD-2/Dowex 1-X8 tandem column. When the extraction efficiency was evaluated by sampling up to 1 L of distilled water, recovery of the phenols, except phenol, was above 90% and the limit of detection of the phenols was 5 ppb. The XAD-2/Dowex 1-X8 method was superior to C18 cartridge in terms of recovery and selectivity.

• Bulletin of the Korean Chemical Society
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• v.23 no.5
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• pp.693-698
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• 2002

A method has been described for the determination of Cu(Ⅱ), Pb(Ⅱ), Ni(Ⅱ), Cd(Ⅱ), Mn(Ⅱ) and Fe(Ⅲ) by flame atomic absorption spectrometry (FAAS) after preconcentration on Amberlite XAD-16 resin, using hexamethyleneammonium-hexamethylenedithiocarbamate (HMA-HMDTC) as a chelating agent, and NH3/NH4Cl buffer solution (pH 9). Influences of various analytical parameters such as pH, concentration of nitric acid, amount of analytes, diverse ions and sample volume were investigated. The relative standard deviation (RSD) and the detection limit (LOD) were found in the range of 0.8-2.9% and 0.006-0.277 ㎍/mL,respectively. Recoveries obtained by the column method were quantitative ( >95%) at optimum conditions.The method was applied to the determination of some metal ions in seawater and wastewater samples. A high preconcentration factor (about 150 for seawater and 75 for wastewater samples) and simplicity are the main advantages of this suggested method.

• KSBB Journal
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• v.9 no.4
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• pp.385-394
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• 1994

Large scale purification to get antifungal antibiotic KRF-001 of 90% purity, was investigated using preparative HPLC. Crude KRF-001 was purified by XAD-7 adsorption chromatography, acid precipitation and microfiltration. Microfiltration was the most effective isolation method of crude KRF-001. The purification methods using C18 chromatography was convenient compared with the conventional methods. Delta PAK C18 column and Bonda PAK C18 column were adapted large scale purification of KRF-001. Gradient system of prep HPLC using Delta PAK C18 column was more effective. With these conditions, final recovery of KRF-001 yielded 77%.

• Analytical Science and Technology
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• v.25 no.5
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• pp.307-312
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• 2012

To perform inhalation toxicity test by using experiment animals, we set up an analytical method to monitor didecyldimethylammonium chloride (DDAC) in aerosol nebulized into inhalation chambers by ion chromatography. DDAC was adsorbed by XAD-2 resin and analyzed with conductivity detector. Recovery of DDAC desorbed by acetonitrile from XAD adsorbent was 87.8%. The method detection limit (MDL) and the limit of quantitation (LOQ) were 2.97 ${\mu}g/m^3$ and 8.92 ${\mu}g/m^3$, respectively. Repeatability was calculated as RSD 7.8% in the range of 0~20 ${\mu}g/mL$. Time needed to analyze a sample was less than 5 minutes. Therefore, the analysis of DDAC by ion chromatography was practically useful in monitoring DDAC in inhalation chambers with rapidity and sensitivity manner to perform inhalation toxicity test using experimental animals.