• Biotechnology and Bioprocess Engineering:BBE
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• v.6 no.6
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• pp.363-375
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• 2001

Chromatography has been method of choice for the separation complex biologi-cal mixtures fro analytical purpose, particularly for the last fifty years. Its use has recently been extended to preparative separation where the productivity relative to the amount of resin and sol-vent used is a matter of concern. To overcome the inherent thermodynamic inefficiency of batch chromatography, as exemplified by the partial temporal usage of the resin and dilution of the product with the solvent, chromatography has been continually modified by separation engineers. Column switching and recycling represnet some of the process modifications that have brought high productivity to chromatography. Recently, the simulated moving bed (SMB) method, which claims a high separation efficiency based on counter-current moving bed chromatography. has be-come the mainstay of preparative separation, especially in chiral separation. Accordingly, this pa-per reviews the current status of SMB along with several chromatographic modification, which may be helpful in routine laboratory and industrial chromatographic practices.

• Mass Spectrometry Letters
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• v.12 no.4
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• pp.186-191
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• 2021

A new method for chemical separation of light rare-earth elements (LREEs) using gas-pressurized extraction chromatography (GPEC) is described. GPEC is a microscale column chromatography system that features a constant flow of solvents, which is created by pressurized nitrogen gas. The separation column with a Teflon tubing was packed with LN resin. The proposed GPEC method facilitates production of lesser chemical wastes and faster separation owing to the use of low solvent volume compared to traditional column chromatography. We evaluated the separation of Ba, La, Ce, and Nd using various elution solvents. The column reproducibility of the proposed GPEC system ranged from 2.4% to 4.9% with RSDs of recoveries, and the column-to-column reproducibility ranged from 3.1% to 6.3% with RSDs of recoveries. The proposed technique is robust, and it can be useful for the fast separation of LREEs.

• Journal of Oral Medicine and Pain
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• v.25 no.1
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• pp.9-28
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• 2000

The purpose of this article, the first part of series, is to describe the general theory applicable to various chromatographic procedures. History of chromatography, separation of matters, classification of chromatography, underlying principles of separation in chromatography, covering resolution, column efficiency, column selectivity, and capacity factor, movement of solute in chromatographic phase, including elution development, displacement development, and frontal analysis, were discussed. Mathematical description of plate theory and thermodynamic viewpoint of retention were emphasized.

• Biotechnology and Bioprocess Engineering:BBE
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• v.9 no.4
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• pp.285-291
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• 2004

A simulated moving bed (SMB) chromatography system is a powerful tool for preparative scale separation, which can be applied to the separation of chiral compound. We have de-signed our own lab-scale SMB chromatography using 5 HPLC pumps, 6 stainless steel columns and 4 multi-position valves, to separate a racemic mixture of ketoprofen in to its enantiomers. Our design has the characteristics of the low cost for assembly for the SMB chromatography and easy repair of the unit, which differs from the designs suggested by other investigators. It is possible for the flow path through each column to be independently changed by computer control, using 4 multi-position rotary valves and 5 HPLC solvent delivery pumps. In order to prove the operability of our SMB system, attempts were made to separate the (S)-ketoprofen enantiomer from a ketoprofen racemic mixture. The operating parameters of the SMB chromatography were calculated for ketoprofen separation from a batch chromatography experiment as well as by the triangle theory. With a feed concentration of 1 mg/mL, (S)-ketoprofen was obtained with a purity of 96% under the calculated operating conditions.

• Bulletin of the Korean Chemical Society
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• v.26 no.4
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• pp.569-574
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• 2005

A coupled column liquid chromatography system was applied for the separation of the burnup monitors in spent nuclear fuel sample solutions. A reversed phase column was studied for the adsorption behavior of uranyl ions using alpha-hydroxyisobutyric acid as an eluent and used for the separation of plutonium and uranium. A cation exchange column prepared by coating 1-eicosylsulfate onto the reversed phase column was used for the separation of the lanthanides. In addition, retention of Np was checked with the reversed phase column and cation exchange column, respectively, according to the oxidation states to observe the interference effect for the separation of burnup monitors. This chromatography system showed a great reduction in separation time compared to a conventional anion exchange method. A good agreement from the burnup data was obtained between for this method and a conventional anion exchange method to within 1% of a difference for the spent nuclear fuel samples of about 40 GWD/MTU.

• Biotechnology and Bioprocess Engineering:BBE
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• v.5 no.1
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• pp.17-22
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• 2000

The separation of tryptophan enantiomers was carried out with medium-pressure liquid chromatography using BSA (bovine serum albumin)-bonded silica as a chiral stationary phase. The influence of various experimental factors such as pH and ionic strength of mobile phase, separation temperature, and the presence of organic additives on the resolution was studied. In order to expand this system to preparative scale, the loadability of sample and the stability of stationary phase for repeated use were also examined. The separation of tryptophan enantiomers was successful with this system. The data indicated that a higher separation factor (a) was obtained at a higher pH and lower temperature and ionic strength in mobile phase. Addition of organic additives (acetonitrile and 2-propanol) in mobile phase contributed to reduce the retention time of L-tryptophan. About $30\%$ of the separation factor was reduced after 80 days of repeated use.

• Journal of Radiopharmaceuticals and Molecular Probes
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• v.7 no.2
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• pp.69-77
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• 2021

No-carrier-added holmium-166 (n.c.a ¹⁶⁶Ho) separation is performed based on the results of separation conditions using stable isotopes dysprosium (Dy) and holmium (Ho) to minimize radioactive waste from separation optimization procedures. Successful separation of two adjacent lanthanides was achieved by cation-exchange chromatography using a sulfonated resin in the H+ form (BP-800) and α-hydroxyisobutyric acid (α-HIBA) as eluent. For the identification process after separation of stable isotopes, the use of chromogenic reagents alternatively enables on-line detection because the lanthanides are hardly absorb light in the UV-vis region or exhibit radioactivity. Four different chromogenic reagents were pre-tested to evaluate suitable coloring reagents, of which 4-(2-Pyridylazo)resorcinol is the most recommendable considering the sensitivity and specificity for lanthanides. Lanthanide radioisotopes (RI) were monitored for separation with an RI detector using a lab-made separation LC system. Under the proper separation conditions, the n.c.a ¹⁶⁶Ho was effectively obtained from a large amount of 100 mg dysprosium target within 2 hrs.

• Korean Chemical Engineering Research
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• v.48 no.1
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• pp.88-92
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• 2010

DNA structure studies attract many interests in pharmaceutical, biochemical and medical disciplines. Among them, base pairs play a vital role in biological information transfer. Therefore, they need to be analyzed in various ways and the pair of guaninine and cytosine is the present analytical object. Separation of guanine and cytosine was researched by Aspen chromatography simulator and HPLC(High Performance Liquid Chromatography) experiments. Aspen chromatography simulation resulted in various chromatograms with changes of sample concentration, eluent flow rate and number of plate. The resolutions and yields of guanine and cytosine were calculated to obtain a best separation condition. $C_{18}$ HPLC column and water/methanol/acetic acid mixture(90/10/0.2) were used for separation of guanine and cytosine. HPLC parameters(resolution and number of theoretical plate) were calculated under different flow rates and sample concentrations. Aspen chromatography simulation and HPLC experimental results were compared with fair agreement.

• KSBB Journal
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• v.23 no.2
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• pp.135-141
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• 2008

SMB (simulated moving bed) chromatography is a very useful utility for the separation of binary system. We simulated the separation of L-arabinose and L-ribose from the mixture by using lab-scale 4(1-1-1-1)-zone SMB chromatography. Preliminary experiments of PIM (pulse input method) were performed to measure adsorption isotherms of L-ribose and L-arabinose in $NH_2$ HPLC column, and experimental and simulated results from ASPEN chromatography were compared. To find the most suitable separation condition in SMB, we carried out a simulation in $m_2-m_3$ plane base on the triangle theory and calculated operating parameters (flow rate of four zone, switching time and feed concentration and so on) using ASPEN chromatography under the conditions of linear isotherms obtained from PIM.

• Analytical Science and Technology
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• v.37 no.2
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• pp.123-129
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• 2024

We present a rapid method for the determination of Cs, Sr, and Ba, heat generators found in highly active liquid wastes, by gas-pressurized extraction chromatography (GPEC) using a column containing a cation-exchange resin. GPEC is a microscale column chromatographic technique that uses a constant flow rate of solvent (0.07 mL/min) with pressurized nitrogen gas supplied through a valve. In particular, because this method uses a small sample volume (a few hundred microliters), it produces less chemical waste and allows for faster separation compared to traditional column chromatography. In this study, we evaluated the separation of Cs, Sr, and Ba using GPEC. The eluate from the column (GPEC or conventional column chromatography) was quantitatively analyzed using inductively coupled plasma-mass spectrometry to measure the column recovery and precision. The column reproducibility of the proposed GPEC system (RSDs of recoveries) ranged from 2.7 to 4.1 %, and the column recoveries for the three elements ranged from 72 to 98% when aqueous HCl was used as the eluent. The GPEC results are slightly different in efficiency and separation resolution compared to those of conventional column chromatography because of the differences in the eluent flow rate as well as the internal diameter and length of the column. However, the two methods had similar recoveries for Cs and Sr, and the precision of GPEC was improved by two-fold. Remarkably, the solvent volume required for GPEC analysis was five times lower than that of the conventional method, and the total analysis time was 11 times shorter.