Columns plate

Now, TsK +Vm is the effective cell volume of the detector in much the same way that (ca) is the column plate volume. ... 

FIGURE 2.6 Resolvability of SEC. The molecular mass ratio needed for the complete resolution of solutes of various shapes as a function of column plate number. The influence of pore volume is given by the designations (Ip), which stands for low porous for which Vp/Vo is 0.7S, and (hp), which stands for highly porous for which Vp/Vp is typically 2.0. [Reproduced from Hagel (1993), with permission.]... 

There are different ways to calculate the theoretical plate count of a column. PSS SEC column plate counts are measured using the so-called half-height method. Figure 9.9 shows a graphic representation of this test. 

All packing materials produced at PSS are tested for all relevant properties. This includes physical tests (e.g., pressure stability, temperature stability, permeability, particle size distribution, porosity) as well as chromatographic tests using packed columns (plate count, resolution, peak symmetry, calibration curves). PSS uses inverse SEC methodology (26,27) to determine chromatographic-active sorbent properties such as surface area, pore volume, average pore size, and pore size distribution. Table 9.10 shows details on inverse SEC tests on PSS SDV sorbent as an example. Pig. 9.10 shows the dependence... 

FIGURE 9.12 Quality control chart of PSS SDV columns plate count (per m) measurements over a I0>year period 5% limits are also shown. 

Platten-gewebe, n. lamellar tissue, -glimmer, m. sheet mica, -gummi, n. plate rubber sheet rubber, -kaik, m. slab limestone, -kautschuk, n. plate rubber sheet rubber, -kondensator, m. (Elec.) plate condenser, -kultur, /. plate culture, -kupfer, n. sheet copper, -pulver, n. (Expl.) rolled powder, flake powder, -achale, /. flat dish, specif. Petri dish, -turm, m. plate column, plate tower, -zink, n. slab zinc, plattgedriickt, a. flat-pressed, flattened, plattieren, jj.t. plate clad. 

The column plate count was determined from the expression... 

Bubble column Loop reactor Packed column Plate column Monolithic reactor... 

Column reactors (packed beds, bubble columns, packed bubble columns, plate bubble... 

The liquid volumes in the still, reflux drum and on the column plates are well-mixed regions of uniform composition. 

The column plates have 100 percent plate efficiency and act as theoretical plates. 

A batch still corresponding to a total separation capacity equivalent to eight theoretical plates (seven plates plus the still) is used to separate a hydrocarbon charge containing four (A, B, C, D) simple-hydrocarbon components. Both the liquid and vapour dynamics of the column plates are neglected. Equilibrium data for the system is represented by constant relative volatility values. Constant molar overflow conditions again apply, as in BSTILL. The problem was originally formulated by Robinson (1975). 

Assuming theoretical plate behaviour for both the column plates and the still, the corresponding vapour compositions are given by... 

The A term represents the contribution from eddy diffusion, the B term the contribution from longitudinal diffusion, and the C terms the contributions from mass transfer in the mobile and stationary phases to the total column plate height. By differentiating equation (1.31) with respect to the mobile phase velocity and setting the result equal to zero, the optimum values of mobile phase velocity (u ) and plate height (HETP ) can be obtained. 

Column Type Length m Internal Diameter mm Film Thickness /tm Phase Ratio Capacity Factor lU mm opi cm/s Column Plate Count Plates Per Meter... 

Column Length (cm) Particle Diameter (micrometers) Column Plate Count Plates Per Meter Relative Operating Pressure... 

The general approach for kinetic optiaization of open i tubular columns has been to adopt the familiar Golay equation T (equation 1.34) and to assuae that the aobile phase can be approximated by an incompressible fluid with ideal gas properties, (44-50). Circumstances that are approximate at best but serve adequately to demonstrate some of the fundamental characteristics of open tubular columns operated at low fluid densities. The column plate height equation can be written in the form given in M equation (6.1)... 

RELATIVE CONTRIBUTION (PERCENTAGE BASIS) OF MASS TRANSFER RESISTANCE IN THE MOBILE AMD STATIONARY PHASE TO COLUMN PLATE HEIGHT FOR A SERIES OF 0.32 mm I.D. OPEN TUBULAR COLUMNS USING UMDECAME AT 130 C AS THE TEST SOLUTE... 

Establish control charts of instrumental performance. Day-to-day variations in pump flow rate, relative response factors, absolute response to a standard, column plate counts, and standard retention times or capacity factors are all useful monitors of the performance of a system. By requiring that operators maintain control charts, troubleshooting is made much easier. The maintenance of control charts should be limited to a few minutes per day. 

Standards and blanks are the usual controls used in analytical HPLC. Standards are usually interspersed with samples to demonstrate system performance over the course of a batch run. The successful run of standards before beginning analysis demonstrates that the system is suitable to use. In this way, no samples are run until the system is working well. Typically, standards are used to calculate column plate heights, capacity factors, and relative response factors. If day-to-day variability has been established by validation, the chromatographic system can be demonstrated to be within established control limits. One characteristic of good science is that samples... 

Figure 6.1a, b. Column plates. Time base mid-2004 (for column costs see Figure 6.4) Installed cost = (cost from figure) x Material factor...

Solvent recovery column plate column, diameter 0.6 m, height 6 m, 10 stainless steel sieve plates, design pressure 2 bar, column material carbon steel. 

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