Permeation limit

The selective separation range of P-6/S-200 was determined with Blue Dextran (Vexdi exclusion limit) and fructose (V,o total permeation limit). Molecular weight (degree of polymerization) calibration (Fig. 16.22) was established with dextran standards and low dp pullulans (dp 3, 6, 9, 12, 15, 18) formed by the controlled hydrolysis of high dp pullulan. 

Hi) The curve, thus obtained, normally approximates to a straight line within the exclusion and total permeation limits,... 

Reactant permeation limits the achievable conversion increase. 

The other validation test that is used to approve containers for use with sensitive preparations is the moisture permeability test. This evaluation is notably more complex in that it sets permeation limits based both on the type of container and the classification of the material being stored within. In general, these tests measure the performance of the packaging system but offer no design guidance. For compendial applications, permeability testing of plastics are described in the USP general chapters (661) and (671) for all types of containers. 

Ion exchange of sample (bands elute aher total permeation limit) Hydrophobic lelentioii (bands dute after total permeation limit)... 

The Mark-Houwink constants K and a were determined for PEEK and polystyrene at 115°C in the phenol-TCB mixture (see Table 4.2). A typical chromatogram showed, in addition to the molecular distribution of the polymer, two solvent peaks, one positive and one negative. These occur beyond the permeation limit of the columns and did not interfere with the molecular mass distribution of the polymer. Narrow-distribution polystyrenes, PEEK samples characterized by light-scattering, and model low-molecular-mass compounds were used as molecular-mass standards. 

FIOURE 28<27 a) Calibration curve for a size-exclusion column. 03) Chromatogram showing peak A containing all compounds with molecular masses greater than the exclusion limit, peaks B and C consisting of compounds within the selective permeation region, and peak D containing all compounds smaller than the permeation limit. 

Only the current conditions, charging conditions, or permeation limiting case described before are considered here, so Eq. (12b) apphes. Application of the steady state Equations (33) and (12b), using the expressions (23)-(32), allows one to derive analytical expressions for 0j and versus the potential and for each HER mechanism [61],... 

On the basis of this model, it is possible to predict the ASB effects on the bulk H concentration [60,67,68], assuming that there is a common Hj intermediate for the HER and the HAR and that in the steady state the surface-bulk transfer step is in equilibrium (H charging) or quasiequilibrium (H permeation limited by bulk diffusion). 

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