• Mass Spectrometry Letters
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• v.2 no.3
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• pp.65-68
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• 2011

The effects of column length and particle size on the efficiency of separation and characterization of phospholipids (PLs) are investigated using nanoflow liquid chromatography-electrospray ionization-tandem mass spectrometry (nLC-ESI-MS-MS). Since PLs are associated with cell proliferation, apoptosis, and signal transduction, it is of increasing interests in lipidomics to establish reliable analytical methods for the qualitative and quantitative profiling of PLs related to biomarker development in adult diseases. Due to the complexity of PLs, the preliminary separation of PLs is necessary prior to MS analysis. In this study, length of capillary column and the particle size of reversed phase ($C_{18}$) packing materials are varied to find a reliable condition for the high speed and high resolution separation using 8 PL standard mixtures. From experiments, it was found that a capillary column of nLC-ESI-MS-MS analysis for PL mixtures can be minimized to a 5 cm long pulled tip column packed with 3 ${\mu}m$ $C_{18}$ particles without losing resolution.

• Journal of Korean Society on Water Environment
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• v.20 no.2
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• pp.104-109
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• 2004

Removal of nutrients from domestic sewage or industrial wastewater is needed to protect surface waters from eutrophication. This research was carried out to remove the nitrogen (N) and phosphorus (P) from the wastewater using the iron oxide obtained from the steel industry and the natural zeolite, respectively. This research was conducted in both batch and continuous systems. The removal efficiency of the nutrients was evaluated in the batch system using the varying concentrations of zeolite and iron oxide added. The removal efficiency of N was 60% at the 8g of zeolite added. In the same condition, the removal efficiencies of N were 76% and 82% at 12g and 16g of zeolite added, respectively. Removal efficiency of P was 80% as 8g of iron oxide was added. The removal efficiency of P was correspondingly increased as the concentration of iron oxide was increased. Continuous column system was also used to evaluate the removal efficiency of N and P by the addition of zeolite and ferric oxide, respectively. Removal efficiencies of N were compared in the mixed packing, two stage, and four stage columns, respectively. The removal efficiencies (80%) of N in the separate packed columns (two and four stages) were higher than the mixed packing column (400%) after 90 hr. Whereas, the removal efficiencies of P were similar to each other in the three columns.

• Journal of the Korean Chemical Society
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• v.53 no.3
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• pp.279-285
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• 2009

This paper has described about preparation of $Zr^{4+}$ affinity column based on the poly(styrene-co- gly-cidyl methacrylate) prepared by emulsion polymerization of styrene and glycidyl methacrylate in order to isolate phosphopeptide. The $Zr^{4+}$ ions were introduced after the phophonation of an epoxy group on polymeric microspheres. The successful preparation of $Zr^{4+}$-immobilized polymeric microsphere stationary phase was confirmed through Fourier transform infrared spectra, optical microscopy, scanning electron microscopy, X-ray photoelectron spectra and inductively coupled plasma-atomic emission spectrometer. The separation efficiency for $Zr^{4+}$ affinity column prepared by slurry packing was tested to phosphonated casein and dephosphonated casein. The resolution time (min) of the phosphonated casein was higher than that of dephosphated casein for $Zr^{4+}$ affinity polymeric microsphere by liquid chromatography. This $Zr^{4+}$ affinity column can be used for isolation of phosphonated casein from casein using liquid chromatography.

• Proceedings of the Korean Operations and Management Science Society Conference
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• 2002.05a
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• pp.402-408
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• 2002

Multicast technology allows the transmission of data from one source node to a selected group of destination nodes. Multicast routes typically use trees, called multicast routing trees, to minimize resource usage such as cost and bandwidth by sharing links. Moreover, the quality of service (QoS) is satisfied by distributing data along a path haying no more than a given number of arcs between the root node of a session and a terminal node of it in the routing tree. Thus, a multicast routing tree for a session can be represented as a hop constrained Steiner tree. In this paper, we consider the hop-constrained multicast route packing problem with bandwidth reservation. Given a set of multicast sessions, each of which has a hop limit constraint and a required bandwidth, the problem is to determine a set of multicast routing trees in an arc-capacitated network to minimize cost. We propose an integer programming formulation of the problem and an algorithm to solve it. An efficient column generation technique to solve the linear programming relaxation is proposed, and a modified cover inequality is used to strengthen the integer programming formulation.

• Applied Chemistry
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• v.17 no.1
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• pp.21-24
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• 2013

High performance count-current flow in packedtower design. Column that packed with Montz packing regular and dumped packing with Pall Ring, Hiflow Ring and Hackette have been represented high performance in vaccum rectification and absorption. The new correlating of these relationship based on the numerous results has been developed for process calculation and design. The results of laboratory or experimental pilot plant can be adopted directly for scale-up.

• FOCUS: LIFE SCIENCE
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• no.1
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• pp.1.1-1.4
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• 2024

This article provides comprehensive guidance on the maintenance, cleaning, regeneration, and storage of silica-based HPLC (High-Performance Liquid Chromatography) columns. The general considerations emphasize the importance of using in-line filters and guard cartridges to protect columns from blockage and irreversible sample adsorption. While these measures help, contamination by strongly adsorbed sample components can still occur over time, leading to an increase in back pressure, loss of efficiency, and other issues. To maximize column lifetime, especially with UHPLC (Ultra-High Performance Liquid Chromatography) columns, it is advisable to use ultra-pure solvents, freshly prepared aqueous mobile phases, and to filter all samples, standards, and mobile phases. Additionally, an in-line filter system and sample clean-up on dirty samples are recommended. However, in cases of irreversible compound adsorption or column voiding, regeneration may not be possible. The document also provides specific recommendations for column cleaning procedures, including the flushing procedures for various types of columns such as reversed phase, unbonded silica, bonded normal phase, anion exchange, cation exchange, and size exclusion columns for proteins. The flushing procedures involve using specific solvents in a series to clean and regenerate the columns. It is emphasized that the flow rate during flushing should not exceed the specified limit for the particular column, and the last solvent used should be compatible with the mobile phase. Furthermore, the article outlines the storage conditions for silica based HPLC columns, highlighting the impact of storage conditions on the column's lifetime. It is recommended to flush all buffers, salts, and ion-pairing reagents from the column before storage. The storage solvent should ideally match the one used in the initial column test chromatogram provided by the manufacturer, and column end plugs should be fitted to prevent solvent evaporation and drying out of the packing bed.

• Journal of Korean Institute of Industrial Engineers
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• v.32 no.3
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• pp.219-225
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• 2006

We consider a routing and wavelength assignment (RWA) for the efficient operation of WDM networks. For a given physical network, a set of selected pairs of nodes, the number of required connections for each selected pair of nodes, and a set of available wavelengths, the RWA is to realize as many connections as possible without wavelength collision. We give an integer programming formulation and an algorithm based on column generation. Though the proposed algorithm does not guarantee optimal solutions, test results show that the algorithm gives probably good solutions.

• Fibers and Polymers
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• v.2 no.1
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• pp.135-139
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• 2001

Poly(hydroxamic acid) resin beads were prepared and complexed with various metal ions. We used IR spectroscopy to investigate the structure of metal complex. It proved that the products formed by introduction of metal ions gave stable and colored complex. It was found that the resin bead as synthesized would be a good column packing material for continuous extraction. Energy dispersive spectroscopy was use to study the distribution of metal ions in the resin matrix. It could be tentatively concluded that adsorption and diffusion of metal ions in the chelating resins mainly depended on the loading of the resin matrix which indicated interacting sites with metal ions.

• Clean Technology
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• v.10 no.3
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• pp.159-168
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• 2004

Benzene adsorption experiment was carried out for activated carbon and zeolite 13X adsorbents. Single column and dual column packed with two adsorbents were used to investigate the dynamic adsorptive characteristics. Effect of feed flow rate on the breakthrough curve was not significant. Specific adsorption amount of benzene for activated carbon was larger than that for zeolite 13X. On the contrary, adsorption amount per column volume was larger for zeolite 13X column because the density of zeolite 13X was larger. In the dynamic experiment using dual adsorbents column, length of mass transfer zone was changed by the feed direction. Breakthrough time was longer and breakthrough curve was sharper when activated carbon was packed in feed inlet and zeolite 13X was packed in column outlet. Also breakthrough time and breakthrough curve slope were affected by the packing ratio of the two adsorbents.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.12 no.7
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• pp.3334-3340
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• 2011

In this study, a computer simulation work has been performed for the carbon dioxide removal process using aqueous amine solution in the GTL (Gas To Liquids) process. 30wt% DEA(diethnaol amine) aqueous solution was utilized as a carbon dioxide remvoal agent and an absorber-stripper two-columns configuration was used. Kent-Eisenburg modeling equation built-in amine specicial package was used for the modeling of the carbon dioxide removal process. PRO/II with PROVISION 9.0, a commercial process simulator was used. Through this simulation study, heat and material balance was obtained and packing column diameter and column height were also estimated.