Volume interstitial

The entire interstitial volume must pass through the column before any polymer emerges. Then the first polymer that does appear is the one with the highest... 

Vm ) can be initially divided into two parts, that contained in the pores (Vn) and that contained in the interstitial volume between the particles (Vj), thus,... 

In addition, the interstitial volume can also be divided into two parts, the interstitial volume that is actually moving (V (m)) nd that part of the interstitial volume around the points of contact of the particles that is static (Vi(s)). 

It is important to realize that all static phases will contribute to retention and, as a result, a number of different distribution coefficients will control the retention of the solute. Nevertheless, the situation can be simplified to some extent. The static interstitial volume (Vi(s)) and the pore volume fraction (Vp(i)) will contain mobile... 

Equation (36) is certainly more accurate than equation (34) but still does not take into account any exclusion properties that the support may have. In addition, the particles are close-packed and touching so, in the interstitial volume, around the points of contact, some additional solute exclusion will almost certainly take place. The pore... 

Total Interstitial Volume, value extrapolated from the retention volumes of ions of different size Interstitial Moving Phase Volume... 

F fraction of the static interstitial volume accessible to the solute... 

Recent innovations [19] have circumvented the heat dissipation and sample stream distortion inherent in most of the previous designs. In one apparatus, developed by R S Technologies, Inc. (Wakefield, RI, USA), Teflon capillary tubes are aligned close to each other in the electrophoretic chamber. Coolant is pumped through the Teflon capillary tubes during the electrophoretic run while the electrophoretic separation is accomplished in the interstitial volume between the Teflon tubes. 

Ve = elution volume Vo = interstitial volume Vt = total bed volume X = model parameter, Eq. (67) z = charge on solute... 

The porous glass packed columns did not yield high resolution separations, but the major species present in a latex were adequately separated. Figure 1. Insoluble polymer, when present, was excluded from the pores and eluted at interstitial volume. Elution order of remaining species was soluble polymer, unreacted monomers, and water. In both types of resins studied, no separation of the two unreacted monomers was achieved. A single chromatographic peak, that included both monomers, was obtained. 

FIGURE 6.14 (a) Principle of SBCD, elution with five interstitial volumes on 4-cm distance (5x4 cm) is faster than single development on 20-cm distance (thick line), (b) Rp values of sample components plotted as a function of modifier concentration. Optimal concentration (Y) for SBCD (5x4 cm) is lower than for development on the full distance of 20 cm (X). (Modified from Soczewinski, E., Chromatographic Methods Planar Chromatography, Vol. 1, Ed., Kaiser R.E., Dr. Alfred Huetig Verlag, Heidelberg, Basel, New York, 1986, pp. 79-117.)... 

In exclusion chromatography, the total volume of mobile phase in the column is the sum of the volume external to the stationary phase particles (the void volume, V0) and the volume within the pores of the particles (the interstitial volume, Vj). Large molecules that are excluded from the pores must have a retention volume VQ, small molecules that can completely permeate the porous network will have a retention volume of (Vo + Fj). Molecules of intermediate size that can enter some, but not all of the pore space will have a retention volume between VQ and (V0 + Fj). Provided that exclusion is the only separation mechanism (ie no adsorption, partition or ion-exchange), the entire sample must elute between these two volume limits. 

In Fig. 3.4d the relative molecular mass of the solute, Mr, is plotted on a log scale against the retention volume. The interstitial volume, which represents the volume range within which separations occur, and the size range of solutes that are eluted in this volume range, depend on the sort of material that is used for the stationary phase. Because for a given separation, F0 and V are constant, we can reliably predict the total volume of solvent or the time taken for a particular analysis. The calibration curve is established by determining the retention volume for standards of known Mr. 

I A 7.8 mm x 30 cm column containing the 104 A stationary phase above is used with methylbenzene as the mobile phase at a flow rate of 1.1 cm3 min 1. A sample of polystyrene standards dissolved in benzene is injected. The standards have molecular masses of 775 000, 442 000, 6200 and 2800. The void volume of the column is 6 cm3 and the interstitial volume is 5 cm3. 

Ad. 3. Manipulation of intra-f extra-cellular ration. Le Rumear et al24 manipulated intra-/extra-cellular ratios and showed that an increase in vascular volume induced by nerve stimulation increased the fraction of the slow relaxation component, while reduced intra-cellular/interstitial volume induced by osmotic diuresis decreased the fraction of the fast relaxing component and increased the fraction of the slow relaxing component, which indicates that the fast and slow relaxing component can be ascribed to the intra- and extra-cellular space, respectively. 

Selectivity is a relative term and is defined in the Molex process as the adsorbent s preference for desired component (in this case, normal paraffins) over the undesired feed components (cyclic paraffins, iso-paraffins, aromatics) while employing a particular desorbent. One can easily determine an adsorbent and desorbent combination selectivity using a pulse test screening apparatus. This apparatus consists of a known volume of adsorbent placed in a fixed bed. A stream of desorbent is then passed over the bed to fill the pore and interstitial volume of the bed. A known quantity of feed is introduced to the feed at the top of the adsorbent bed and passed across the column as a pulse of feed. This pulse of feed is then pushed through the adsorbent bed using a known desorbent flow rate. Effluent from the column is monitored for the various feed components and the concentrations of each component noted (with respect to time) as they elude from the... 

In the model described in this work every effort has been made to ensure that it embodies physically meaningful parameters. It is inevitcible, however, that some simplistic idealizations of the physical processes involved in GPC must be made in order to arrive at a system of equations which lends itself to mathematical solution. The parameters considered are, the axial dispersion, interstitial volume fraction, flow rate, gel particle size, column length, intra-particle diffusivity, accessible pore volume fraction and mass transfer between the bulk solution eind the gel particles. 

The total exclusion chromatogram provides the means to obtain the e values and this was found to be 0.423. It is interesting to compare this value with that reported ( ) for the interstitial volume of randomly packed rigid spheres which is 0.364. We assume that our value deviates from the hard sphere value primarily because of the inefficient packing of particles in the case of the column used in this work varied substantially in size (35 -75 p). 

Size exclusion chromatography (SBC) is a separation process by which molecules are fractionated by size on the basis of differential penetration into porous particulate matrices. Blution volume (Vq) of any given molecular species relative to another of different size is dependent on the pore diameter of the matrix, pore-size distribution, pore volume (Vp, interstitial volume (Vq) and column dimensions. Use of SBC to estimate molecular size is achieved by plotting the log of the molecular weight of a series of calibrants against their elution volume. Since Vg is a function of Vg and Vj, its magnitude will be dependent on the geometry of a column. 

---