Size column

If only small quantities of powder are available, columns down to 2 in (50 mm) in diameter can be used but diameters not less than 4 in (100 mm) are recommended whenever possible. This is to minimize the wall effects and also to increase the accuracy of air flow measurement. 

As the settled depth should be about 2 ft (60 cm), the column should be about 4 ft tall (120 cm) and preferably increase in diameter above the 4 ft level in order to reduce entrainment. 

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The data covered column sizes up to 50-mm (2-in) diameter the correlation should be used with caution for larger columns. 

FIG. 22-12 Pulsed -column capacity versus column size for 65 percent p-xylene feed. To convert gallons per hour to cubic meters per hour, multiply hy 0.9396 to convert square feet to square meters, multiply hy 0.0929. (McKay et al., prepr., 59th nat. meet. AIChE, East Columbus, Ohio.)... 

A trend in chromatography has been to use monosized particles as supports for ion-exchange and size-exclusion chromatography and to minimize the column size, such as using a 15 X 4.6-mm column packed with 3-/rm polymer particles for size exclusion chromatography. The more efficient and lower back pressure of monosized particles is applied in the separation. 

BioProcess stainless-steel columns are fixed bed height columns designed for the most stringent requirements in the routine production of biopharmaceuticals. Wetted materials include stainless steel, polypropylene, and EPDM. The BPSS series may be operated at pressures up to 3 bar (0.3 MPa) and are supplied with sanitary fittings of 10 or 22 mm i.d. The available column sizes and specifications for the BPSS column series are given in Table 2.18. 

With soft gels, column packing has often been plagued with such problems as inferior reproducibility and excessive time requirements. These problems are alleviated with physically stable Toyopearl HW media. However, an improperly packed column can have significantly reduced efficiency. The two key variables for the successful packing of Toyopearl HW media, packing velocity and column size, have been evaluated to determine the optimal packing conditions. 

Toyopearl resin Column size Linear veiocity (cm/hr) Fiow rate (mi/min)... 

In-column solvents Column size (mm) Theoretical plate number Exclusion limit Poiystyrene PEG Particle size (/urn) Pore size (A) Flow Rate (ml/min) Maximum pressure (kgf/cm ) Maximum temperature (°C)... 

Column type Column size (mm) Theoretical plate number Range Flow rate (ml/min) Max Analytical column... 

Generally, size exclusion chromatography is carried out using columns with an internal diameter of 7.8 mm. However, some SEC applications require the use of expensive solvents. For this purpose, size exclusion columns with a smaller internal diameter (4.6 mm) have been developed. Of course one should use proportionally lower flow rates with narrow-bore columns. If the standard column size uses a flow rate of 1 ml/min, then the smaller 4.6-mm columns should be used at a flow rate of 0.35 ml/min. This provides the same linear velocity as 1 ml/min on 7.8-mm columns. The decreased flow rate reduces solvent consumption and solvent disposal cost. The performance of the smaller diameter columns is not compromised if properly optimized instrumentation is used. 

Fig. 3-1. Separation of racemic 3,5-dinitrobenzamido leucine Al.A -diallylamide on silica and polymer-based chiral stationary phases. Conditions column size 150 x 4.6 mm i.d. mobile phase 20 % hexane in dichloromethane flowrate 1 mL min injection 7 pg. Peaks shown are l,3,5-tri-rert.-butylbenzene (1), R-enantiomer (2) 5-enantiomer (2 ). (Reprinted with permission from ref. [8]. Copyright 1997 American Chemical Society.)...

Fig. 11a. Fractionation of (/) chymotrypsinogen A, (2) cytochrome C and (3) lysozyme on strong cation exchangers, a) Support Fractogel TSK 650(s)SP (conventional type) sample, 1 mg each flow rate, 1 ml/min column size, 150 x 10 mm T.D. Solvent A = 0.02 mol/1 phosphate, pH 6.0 solvent B = A + 1 mol/1 NaCl gradient, 0-10 min, 0% B 10-70 min, 0-100% B. b) Support Fractogel EMD 650(s)SO( — (tentacle type) conditions as in (a) [78]...

In most cases the analyst must choose a column size that is commercially available and fortunately most manufactures provide an appropriate range of sizes. It is interesting to note that, although the predictions of Martin and Synge were correct and small particles give the smallest HETP and the highest efficiencies, there is a caveat to this argument. 

Figure 3. The profile of pectinase on Figure 4. The profile of pectinase on hydroxyapatite column chromatograph Toyopearl 55HW gel filtration column size 1x60 mm, 10-500 mM phosphate size 1.1x55 cm. flow rate 15 ml/h, 50 buffer pH 5.8, flow rate 12 ml/h mM acetate buffer pH 5.25...

Fig. 1. Separation of two exopolygalacturonase groups (Fraction A, Fraction B) on CM-Sephadex C-50. Column size, 20x250 mm. Stepwise elution with 0.05 M acetate buffer, pH 3.8 (starting at arrow marked a), 0.10 M acetate buffer, pH 4.8 (at arrow marked b), 0.15 M acetate, pH 5.6 (at arrow marked c) and the latter buffer plus 1.0 M NaCl (at arrow marked d). Fraction size 6 ml per half hr. Exopolygalacturonase activity determined with sodium pectate, pH 5.0 (o—O) 2nd expressed as A,, .

In order to reduce the time-consuming open-column chromatographic processes, conventional methods of hydrocarbon-group-type separation have been replaced by MPLC and HPLC. Flash column chromatography is a technique less commonly applied than open-column version, but several applications have been described [2,24—27]. The common technique version is to use a silica-gel-filled column for example, 230 to 400 mesh 20 X 1 cm column size with a back pressure of 1.5 X 10 Pa of an ambient gas such as nitrogen. Solvents are similar to the ones apphed in the case of open-column chromatography fractionations. 

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