• Membrane and Water Treatment
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• v.13 no.4
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• pp.201-208
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• 2022

Emulsion Liquid Membrane (ELM) is a prominent technique for the separation of heavy metal ions from wastewater due to the fast extraction and is a single-stage operation of stripping-extraction. The selection of the components (Surfactant and Carrier) of ELM is a very significant step for its preparation. In the ELM technique, the primary water- in-oil (W/O) emulsion is emulsified in water to produce water-in-oil-in-water (W/O/W) emulsion. The water in oil emulsion was prepared by mixing the membrane phase and internal phase. To prepare the membrane phase, the extractant D2EHPA (di-2-ethylhexylphosphoric acid) was used as a mobile carrier, Span-80 as a surfactant, and Paraffin as a diluent. Moreover, the internal (receiving) phase was prepared by dissolving sulphuric acid in water. Di-(2- ethylhexyl) phosphoric acid such as surfactant concentration, carrier concentration, sulphuric acid concentration in the receiving (internal) phase, agitation time (emulsion phase and feed phase), the volume ratio of the membrane phase to the receiving phase, the volume ratio of the external feed phase to the primary water-in-oil emulsion and pH of feed were studied on the percentage extraction of metal ions at 20℃. The results show that it is possible to remove 78% for As(V), 98% for Cd(II), and 99% for Pb(II). Emulsion Liquid Membrane (ELM) is a well-known technique for separating heavy metal ions from wastewater due to the fast extraction and is a single-stage operation of stripping-extraction. The selection of ELM components (Surfactant and Carrier) is a very significant step in its preparation. In the ELM technique, the primary water-in-oil (W/O) emulsion is emulsified to produce water-in-oil-in-water (W/O/W) emulsion. The water in the oil emulsion was prepared by mixing the membrane and internal phases. The extractant D2EHPA (di-2-ethylhexylphosphoric acid) was used as a mobile carrier, Span-80 as a surfactant, and Paraffin as a diluent. Moreover, the internal (receiving) phase was prepared by dissolving sulphuric acid in water. Di-(2-ethylhexyl) phosphoric acid such as surfactant concentration, carrier concentration, sulphuric acid concentration in the receiving (internal) phase, agitation time (emulsion phase and feed phase), the volume ratio of the membrane phase to the receiving phase, the volume ratio of the external feed phase to the primary water-in-oil emulsion and pH of feed were studied on the percentage extraction of metal ions at 20℃. The results show that it is possible to remove 78% for As(V), 98% for Cd(II), and 99% for Pb(II).

• Proceedings of the Korean Radioactive Waste Society Conference
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• 2017.05a
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• pp.334-335
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• 2017

• Korean Journal of Fisheries and Aquatic Sciences
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• v.52 no.5
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• pp.461-467
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• 2019

Several studies investigating the prevention and treatment of external parasites in farmed olive flounder Paralichthys olivaceus have found that the anticoccidial agent toltrazuril sulfone is an effective antiparasitic. Prior to undertaking a full-scale study, we developed analytical methods to detect the levels of toltrazuril and toltrazuril sulfone in farmed flounder samples using liquid chromatography-electrospray ionization tandem mass spectrometry (LC-MS/MS). This analysis showed that LC-MS/MS changed the mobile phase and collision energy of toltrazuril and toltrazuril sulfone. This was validated using established conditions. Sample pre-treatment for this process involved extraction with dichloromethane and purification by liquid-liquid extraction in formic acid, acetonitrile, and h-hexane, followed by determination of all compounds by LC-MS/MS. Separation was achieved within 10 min by gradient elution using a Capcell Pak C18 ($3.0{\mu}m$, $100{\times}2.0mm$) analytical column (Shiseido UG 120V) with a mixture of 0.1% (v/v) formic acid and acetonitrile. Multiple reaction monitoring was used for selective detection of toltrazuril and toltrazuril sulfone. This method yields satisfactory results for linearity, precision, and limits of quantification. Therefore, the method established in our study will serve as a basis for further research on parasite control by toltrazuril and toltrazuril sulfone.

• Fisheries and Aquatic Sciences
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• v.4 no.4
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• pp.229-237
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• 2001

In order to identify of volatile flavor compounds and polycyclic aromatic hydrocarbons (PAHs) in commercial liquid smokes, this study was conducted to analyze volatile flavor compounds by solvent extraction and/or Purge & Trap method/GC/MSD. A total of 156 volatile flavor compounds were detected in 6 commercial liquid smokes, and these compounds were composed mainly of 12 aldehydes, 60 ketones, 7 alcohols, 14 acids, 20 esters, 24 aromatic compounds, 7 furans and 12 miscellaneous compounds. Ketones $(806.6-7,573.9\mu g/mL)$ and aromatic compounds $(282.6-7,896.3 \mu g/mL)$ were more abundant than others. The PAHs known as carcinogen have not been detected in this study. The acids $(422.9-4,903.1\mu g/mL)$ was identified in relatively high concentration compared to other groups. Phenol and its derivatives among aromatic compounds were in relatively high concentration. Especially, the phenol and its derivatives including o-cresol, guaiacol, 4-ethylguaiacol and syringol were in higher concentration.

• Bulletin of the Korean Chemical Society
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• v.34 no.6
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• pp.1693-1697
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• 2013

This study develops a novel method to remove the free cations created during the synthesis of ionic liquid. The cations are removed from the ionic liquid by size-selective adsorption onto chemically surface-modified Zeolite. The porous crystal nano-structure of Zeolite has several electron-rich Al sites to attract cations. While large cations of an ionic liquid cannot access the Zeolite nano-structure, small cations like $Na^+$ have ready access and are adsorbed. This study confirms that: $Na^+$ can be removed from ionic liquid effectively using Zeolite; and, in contrast to the conventional and extensively applied ion exchange resin method or solvent extraction methods, this can be done without changing the nature of the ionic liquid.

• Elastomers and Composites
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• v.23 no.1
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• pp.11-17
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• 1988

The transport of chromium(VI) ion from waste water through the liquid surfactant membrane containing tri-n-octylamine as a carrier, was analyzed by a slab model and was investigated through experiments. For the experiment of membrane stability, concentrations of surfactant and liquid paraffin oil were analyzed. Extraction experiments were carried out to observe the effect of system variables, such as concentrations of carrier, and initial chromium(VI) ion in external aqueous phase at $25^{\circ}C$. It is concluded that the most stable formation of liquid membrane emulsion was obtained when surfactant concentration is above 3 wt.% and liquid paraffin oil concentration is 50 vol.%. The theoretical equation on the transport of chromium(VI) ion agreed well with the experimental results.

• Food Science and Biotechnology
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• v.18 no.4
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• pp.978-984
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• 2009

An analytical method for the simultaneous determination of 9 quinolones (QNs) in porcine, chicken, and bovine muscles was developed and validated using liquid chromatography-fluorescence detector (LC-FLD). The samples were extracted using a liquid-liquid extraction (LLE) process. Chromatographic separation was achieved on a reverse phase $C_8$ column with a gradient elution using a mobile phase of 200 mM ammonium acetate buffer (pH 4.5) and acetonitrile (ACN). The proposed method was validated according to the Food and Drug Administration (FDA) guideline for bioanalytical assay procedures. Recoveries of QNs were 83.1-111.9% with relative standard deviations (RSDs) below 15%. Linearity within a range of 30-500 ${\mu}g/kg$ was obtained with the correlation coefficient ($R^2$) of 0.9967-0.9999. The limits of detection (LOD) were 1-16 ${\mu}g/kg$. These values were lower than the maximum residues limits (MRLs) established by the European Union (EU). The present method was successfully applied to determine QNs in edible muscles.

• Bulletin of the Korean Chemical Society
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• v.27 no.2
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• pp.291-294
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• 2006

A highly sensitive high-performance liquid chromatographic-tandem mass spectrometric method (HPLC-MSMS) has been developed to quantify itraconazole in human plasma for the purpose of pharmacokinetic studies. Sample preparation was carried out by liquid-liquid extraction using loratadine as an internal standard. Chromatographic separation used a YMC $C_{18}$ column, giving an extremely fast total run time of 3 min. The method was validated and used for the bioequivalence study of itraconazole tablets in healthy male volunteers (n = 31). The lower limit of detection proved to be 0.2 ng /mL for itraconazole.

• YAKHAK HOEJI
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• v.42 no.2
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• pp.149-152
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• 1998

A high performance liquid chromatographic method was developed for the determination of DA-6034 in biological fluids using internal standard. Plasma containing DA-6034 and inter nal standard was extracted by liquid-liquid extraction at an acidic pH. After evaporation of the organic layer, the drug and internal standard were reconstituted with mobile phase and injected into the column. They were separated by high performance liquid chromatography on inertsil ODS II column at 334 nm. The detection limit of DA-6034 in plasma was 0.02 ${\mu}$g/ml. In this method, the range of recovery and coefficients of variation were 96-110% and 0.40-3.78%, respectively. There was no interference from endogenous substances. Urine and bile were analysed using the deproteinization method and the detection limit of DA-6034 was 1${\mu}$g/l.

• Biotechnology and Bioprocess Engineering:BBE
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• v.3 no.1
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• pp.24-31
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• 1998

The separation and concentration of L-phenylalanine (L-Phe) using a supported liquid membrane (SLM) is investigated. A cation complex agent, di-2-ethylhexyl phosphoric acid (D2EHPA), is used as a carrier in the SLM with n-Heptane as a solvent. The reaction order and equilibrium constant in the formation reaction of L-phe-carrier complex are obtained from the extraction experiment. A mathematical model for a carrier mediated counter transport process is proposed to estimate the diffusion coefficient of L-phe-carrier complexly in the liquid membrant. Permeation experiments of L-phe using a SLM are performed under various operating conditions and optimum conditions for the transport of L-phe are obtained. Concentration of L-phe in the strip phase against its concentration is observed. Transport rate of glucose through liquid membrane is less than that of L-phe in the competitive transport of L-phe and glucose. And the existence of glucose reduced the transport rate of L-phe. The performance of separation with continuous strip phase is increased due to the dilution effect in the strip phase.