Column volume

The actual flotation phenomenon occurs in flotation cells usually arranged in batteries (12) and in industrial plants and individual cells can be any size from a few to 30 m in volume. Column cells have become popular, particularly in the separation of very fine particles in the minerals industry and coUoidal precipitates in environmental appHcations. Such cells can vary from 3 to 9 m in height and have circular or rectangular cross sections of 0.3 to 1.5 m wide. They essentially simulate a number of conventional cells stacked up on top of one another (Fig. 3). Microbubble flotation is a variant of column flotation, where gas bubbles are consistently in the range of 10—50 p.m. 

FIGURE 4.47 Dependence of HETP on sample volume. Column Toyopearl HW-55F, 22 mm X 30 cm. Sample 0.1% myoglobin. Elution 14 mM Tris-HCI, pH 7.9, in 0.3 M NaCI. Flow rate 52 cm/ hr. Detection UV at 220 nm. Legend to. sample injection time Z, column length u. linear velocity. 

Sample loading must be reduced in accordance with the column inside diameter. Polymers exhibit high solution viscosity, and in order to avoid band broadening due to viscous streaming the sample concentration must be reduced for narrow-bore columns. Overloading effects become noticeable at much lower concentrations using 4.6-mm columns compared to 7.5-mm columns because of the effective sample concentration in a smaller volume column. 

Gels made in this way have virtually no usable porosity and are called Jordi solid bead packings. They can be used in the production of low surface area reverse phase packings for fast protein analysis and in the manufacture of hydrodynamic volume columns as well as solid supports for solid-phase syntheses reactions. An example of a hydrodynamic volume column separation is shown in Fig. 13.2 and its calibration plot is shown in Fig. 13.3. The major advantage of this type of column is its ability to resolve very high molecular weight polymer samples successfully. 

Resolution factors Column length ("f) Pore volume ( ) Column length ( ) Column length ( ) Void volume ( ) Column length ( ) Channel thickness ( i )... 

Virial coefficients (GC) 5 Viscosity detector (SEC) 452 Viscous fingering (SEC) 447 Visualization techniques (TLC) (see derivatization (TLC)] Void volume, column (LC) 371 measurement 372 Volman trap (GC) 211 Volume of a theoretical plate 49... 

Relative scale Bed volume Column Height Diameter (cm) (cm) Configuration (height diameter)... 

Figure 6.4 Relationship of log k values measured on ODS-bonded silica gel to Bondi s van der Waals volumes. Column, Develosil ODS, 15 cm x 4.6 mm i.d. eluent, 70% aqueous acetonitrile at 30 °C. Numbers beside symbols see Table 6.4 <>, Polycyclic aromatic hydrocarbons x, alkylbenzenes O, halogenated benzenes A, alkanols and , alkanes.

Figure i A. Calibration curves using a series of narrow MWD polyethylene oxide standards for MicroPak TSK PW column sets. Linear least squares fit for log (MW) vs. elution volume. Column set A MicroPak TSK 3000PW + LOOOPW + 5000PW + 6000PW. 

Figure 2. Relationship between the logarithm of 1 VPC retention volume and the molecular weight of the Disec-butylpolysulfides R = sec-BuLi Tm = 150°C r = retention volume column = 3% OV 17 1.2m.

Once process design is complete and each of the process steps characterized, the process is ready for scale-up to pilot or manufacturing scale. A spreadsheet template for scale-up calculations is important and provides a mass balance of buffer volumes, column volumes, priming volumes, product volumes, and waste volumes as well as the tank size and column size. Product volumes can be expressed relative to column volume or can be calculated from a constant concentration, depending on the process step. In addition, starting volumes and titers of conditioned medium as well as step yields and gel or membrane capacity are necessary to cal-... 

Recovery of Test Solutes. The recovery of test solutes is reported in the data from columns 102-123 (Tables VI-IX). Other than the suite of solutes tested on each column, the columns differ as follows Columns 102-109 used a 50-mL Teflon bed, columns 110-120 used a 150-mL bed, columns 109-120 included 2.0 ppm of humic acid in the influent, and column 102 used 8 bed volumes of methanol for fraction 5, rather than the usual 4 bed volumes. Columns 117, 118, and 120 were replicate runs including 16 test solutes at once, excluding only those solutes that could not be analyzed reliably in the presence of the solutes included. Column 119 was an unspiked control column run with humic acid and used to identify contaminants in the eluates of columns 117,... 

The sample volume is a critical factor in planning a gel chromatography experiment. If too much sample is applied to a column, resolution is decreased if the sample size is too small, the solutes are greatly diluted. For group separations, a sample volume of 10 to 25% of the column total volume is suitable. The sample volume for fractionation procedures should be between 1 and 5% of the total volume. Column total volume is determined by measuring the volume of water in the glass column that is equivalent to the height of the packed bed. 

Expansion volume sample + Solvent) - Liner volume Column flow rate... 

Sample volume is the most fundamental factor to be taken into account when designing an HPLC system in which a small-volume column is used,... 

Description of the high-volume column air sampler (a) illustrates the assembled sampler and its shelter (b) shows the components of a typical high-volume air sampler. 

Mobile phase pH Sample concentration Injection volume Column temperature Flow rate... 

Power up the preparative HPLC system. Set the detector wavelength to 230 nm. Equilibrate the column in 8% Buffer B at 190cm3 min-1 for 22 min. This time is approximately twice the column volume (column volume is —2000 cm3). Record the following ... 

FIGURE 12-5. Example of reverse-phase separation of an APC tablet. Mobile phase MeOH/H20 (4% HO Ac) 25/75. Flow rate 1 mL/tnin. Detector UV at 254 nm, 1.0 AUFS. Sample APC tablet in 100 mL MeOH, 10-p.L injection volume. Column Bondapak Ci8/Porasil B, 2 mm ID x 61 cm. (Note Actual separation will depend upon the quality of the mobile phase and column packing.)... 

In the on-line approach, helium is recommended as the carrier gas to avoid the risk of an explosion in the pyrolysis system. Before pyrolysis, the GC system is optimized with respect to linear gas flow velocity in the column and methane peak shape (indication of dead volumes). Column connections should be made as specified by the column manufacturer. 

The tracer adsorption parameter, 8q, includes tracer adsorption equilibrium constant Kt 0 Y(1 + Kt), and y = P(l-a)/a. P is the pellet porosity and a is the column void fraction (interstitial void volume/column volume). Thus, y, is the pore volume per unit interstitial... 

There are two notable advantages of this technique for the separation of dyes. One is its applicability for the separation of both the ionic and nonionic components of a dye mixture. Second, it has been shown to be one of the best methods for successfully separating small quantities (20 mg or less) of dye mixtures. On the other hand, several hundred milligrams of dye mixtures represent the upper limit beyond which conventional HSCCC cannot be applied as the method of separation when the common 1.6-mm-inner diameter, 325-mL-volume column is used. 

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