• KSBB Journal
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• v.17 no.1
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• pp.88-92
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• 2002

The election profiles with different flow rates of motile phase were experimentally measured to investigate the effects on HETP in capillary gas chromatography. Based on the correlation coefficient ($r^2$), the first and second moments as well as HETP were determined from the elution cuties, and the parameters used in empirical equations were estimated. The empirical equations were expressed in terms of mobile phase velocity, and the theoretical Golay equation was considered. The samples were d-limonene and perillyl alcohol, potential anticancer agent mainly was contained in the peel of orange. From the experimental results, HETP of the samples were increased with mobile phase velocities. The correlation coefficient of d-limonene was in the range between 0.8265 and 0.8465, while that of perillyl alcohol was between 0.9353 and 0.9374. The total HETP was composed of $H_{g}$, $H_{l}$ and Hc, and Hg had the greatest effect on HETP, but HI showed a negligible effect. In terms of HETP, the optimum velocity of mobile phase was present.

• Applied Chemistry for Engineering
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• v.7 no.5
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• pp.985-991
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• 1996

In chromatographic separation, HETP(height equivalent to a theoretical plate) is a useful quanititive parameter and it is wildely designated as column efficiency. The effects of operating conditions (sample concentration, injection volume, flow rate and mobile phase composition) on HETP were investigated in perparative liquid chromatography (PLC). Water and organic modifier of methanol were used as mobile phase. The sample of thymidine was injected into preparative C18 columns. The system was run by a isocratic mode in 1.5~5.5ml/min. The larger amounts of sample and higher flow rates of mobile phase increased HETP, which means that column efficiencies were worse. As the weight of sample injected into a chromatographic system could be prepared with different concentrations and injection volumes, for the same amount of sample, HETP was approximately increased two times with the ten-fold injection volume. HETP was mainly affected by the resistance of stationary and mobile phase mass transfer in the intraparticle section of packings at higher velocities.

• Korean Chemical Engineering Research
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• v.48 no.5
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• pp.668-671
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• 2010

A lab scale distillation experiment is conducted with small size packing used in lab scale multi-tray distillation equipment for the performance evaluation of distillation system. A sufficient surface are yielded with 6.7 mm cylindrical packings made of stainless steel, and a good liquid holdup and residence time are resulted. The comparison between the theoretical tray from the HYSYS and the experimental distillation outcome indicates that a 7 cm HETP from 27 cm packing height and a 8 cm HETP from 45 cm packing height are obtained. Comparing with the 8 cm HETP of commercial structured packing shows a similar experimental results obtained here. The 7 cm HETP is available with a complete insulation, and the importance of the insulation is proved. The results of this study indicates that a practical distillation column used in field can be tested in lab.

• KSBB Journal
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• v.17 no.4
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• pp.326-332
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• 2002

The quality of biopharmaceutical proteins is strongly affected by a manufacturing process employed to produce Et, and thus validation of the manufacturing bioprocess is a very important issue. Chromatography is probably the most widely used bioprocess unit operation for protein purification. In this study, a miniaturized automatic chromatography system was designed and constructed for scale-down studies for process chromatography validation. This system, named MiniValChrom, has the following features: automatic and repeated operation, flexible sequences and intervals among the steps, on-line and real-time monitoring and control, method files savings, etc. Using the MiniValChrom, we peformed a case study of an abbreviated experiment to estimate chromatographic resin lifetime. BSA (bovine serum albumin) and Cibacron Blue 3G-A were used as the model protein and the resin, respectively. The resin deterioration was evaluated by determining and monitoring the HETP and NTP values from the chromatograms every 5 cycles. It was observed that the HETP and the NTP values were changed by 9% after 15 cycles. The resin lifetime validation could be completed by repeating this experiment until the HETP value reached a predetermined value. The MiniValChrom's concept and the protocol suggested in this study can serve as a rapid and economical tool for the validation studies of bioprocess chromatography system.

• Korean Chemical Engineering Research
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• v.54 no.4
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• pp.487-493
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• 2016

The moment analysis of lysozyme was implemented using chromatograms that were obtained from weak cation exchange column in high performance liquid chromatography system. Three elution sodium phosphate buffers containing 1.0, 0.75, 0.5M sodium chloride were used. Experiments were conducted by varying flow rate, elution sodium chloride concentration, and lysozyme solute concentration. The general rate (GR) model was employed to calculate the first moment and the second moment. By plotting $L/u_0$ vs. $({\mu}_1-t_0)/(1-{\varepsilon}_e)(1-{\varepsilon}_i)$] equilibrium constants (K) were obtained from first moment analysis. Intra-particle diffusivity was obtained from theoretical plate number data. Based on the results of moment analysis, van Deemter plots were drawn in order to investigate the contributions of $H_{ax}$, $H_f$, and $H_d$ to total Height Equivalent to a Theoretical Plate (HETP, $H_{total}$). The effect of intra-particle diffusion ($H_d$) was the most dominant factor contributing to HETP while external mass transfer ($H_f$) was negligible factor.

• KSBB Journal
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• v.20 no.3
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• pp.244-249
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• 2005

Chiral separation of racemic ibuprofen was achieved on a Kromasil KR100-5CHI-TBB column. Some chromatographic parameters (resolution, number of theoretical plates, HETP, capacity factor) are calculated under different separation conditions such as change of mobile phase compositions (hexane / t-BME : 85 / 15, 75 / 15, 65 / 35, 55 /45) as well as acetic acid concentrations for adjusting pH (0.1 to 1 $v/v\%$). Flow rate versus number of theoretical plates and HETP were compared to evaluate column efficiency. To determine the adsorption isotherms, PIM (Pulsed Input Method) was carried out. At concentrations of racemic ibuprofen between 0.1 and 0.3 mg/ml, S- and R-ibuprofen have the same retention time of 4.48 and 5.81 min. Ibuprofen isotherms show a linear form under concentrations of 0.3 mg/ml with eluent (hexane / t-BME = 55 / 45).

• Korean Chemical Engineering Research
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• v.53 no.6
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• pp.723-729
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• 2015

The moment analysis of cyclic adenosine monophosphate (cAMP) was performed using chromatograms that were obtained with the pulse input method from an octadecyl silica (ODS) high-performance liquid chromatography (HPLC) column. The general rate (GR) model was employed to calculate the first absolute moment and the second central moment. Three important coefficients for moment analysis, which are molecular diffusivity ($D_m$), external mass transfer coefficient ($k_f$), and intra-particle diffusivity ($D_e$), were estimated by the Wilke-Chang equation, Wilson-Geankoplis equation, and comparing van Deemter equation to theoretical plate number equation, respectively. Experiments were conducted by various conditions of flow rates, methanol volume ratio of the mobile phase, and solute concentration. After the moment analysis, results were organized by van Deemter plots. Also van Deemter coefficients were compared each other to effect $H_{ax}$, $H_f$, and $H_d$ on height equivalent to a theoretical plate (HETP, $H_{total}$). The value of intraparticle diffusion ($H_d$) was the primary factor which makes for HETP whereas external mass transfer ($H_f$) was disregardable factor.

• Journal of the Korean Chemical Society
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• v.31 no.4
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• pp.328-333
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• 1987

1-eicosylsulfate($C_{20}H_{41}SO_4^-$) was coated onto 5 ${\mu}m$ C18 reversed phase column. Adsorption equilibrium was reached when 1.2l of $1.46{\times}10^{-4}M$ in 25% acetonitrile solution passed through the column. This coated column proved to be stable up to 10l of 0.05 M ${\alpha}$-HiBA eluent used. The column efficiencies of Eu, Nd, Ce and La measured were about 0.04 mm of HETP using 0.15M ${\alpha}$-HiBA eluent at a flow rate of 1.0ml/min. This column was used to separate some lanthanides and transition metal ions, andmshowed an excellent resolution, respectively.

• Korean Chemical Engineering Research
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• v.51 no.1
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• pp.93-97
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• 2013

A lab-sized distillation experiment was conducted using small-size packings and a horizontal distillation column. The 6.7 mm Raschig ring type packings of stainless steel and a 40 mm glass column were used, and five independent electric heaters were installed in the axial direction to adjust the column inside temperature separately. The temperature was continuously distributed along the column length to provide equivalent equilibrium to the temperature for the separation. From the experimental results, a larger HETP of the column than the vertical distillation column was obtained, but it was found that the practical separation with proper processing capacity and separation efficiency was available.

• The Journal of Natural Sciences
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• v.5 no.1
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• pp.67-75
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• 1992

In the our country, especially in Yeongil and Wolsung area, abundant authigenic zeolites are found from the tuffaceous sediments and volcanic rocks of Miocene age showing wide variation in their mineralogy and abundance from horizon to horizon. The principal zeolite species identified are clinopti-lolite. mordenite. heulandite. ferrierite, and erionite. etc. Zeolite minerals are widely used in many countries in the following applications; (a) in air separation adsorption processes; (b)as desiccants; (c)in inorganic building materials; (d)in papermaking; (e)in fertilizers; (f)as soilconditioners-this application is based upon the ability of the zeolite to ion exchange with soil nutrients; (g)in the treatment of radioactive wastes; and (h)as adsorbents for toxic gases, etc. In the present paper, using natural zeolite mordenite treated with IN hydrochloric acid or IN sodium chloride solution as column packings, separation characteristics of argon, nitrogen, carbon monoxide, and methane gases have been studied by gas chromatography. By the use of mordenite treated with hydrochloric acid solution, the tailing peak of methane showed from untreated mordenite was satisfactorily reduced, although it was difficult to separate it from carbon monoxide with a column activated at $300^{\circ}C$. Using a column activated at $350^{\circ}C$, methane could be separated from carbon monoxide easily but only carbon monoxide eluted as a bad defined peak. Mordenite treated with sodium chloride solution was generally similar to chromatograms obtained by using the untreated mordenite. Both the above chemical treatments of mordenite had little effect on the separations of argon and nitrogen. The separations and the HETP values obtained from natural zeolite mordenite treated with continuously hydrochloric acid and sodium chloride solutions were almost identical with those obtained with synthetic molecular sieve 5A zeolite. On the other hand, the efficiency of column was good in the range 20~3Oml/min of the carrier helium gas rate.