Dextran scaling parameters

Table I. Comparison of Scaling Parameters for Fullulans and Dextrans...

The values of Vj and Vo are usually determined by the respective standard markers. For example, in the Sephadex G-lOO/aqueous 0.1 M NaOH system, blue dextran (BD) and p-nitrophenol (pNP) are often used as standard markers for Vo and Vj, respectively. In the standardized elution profiles depicted in Fig. 2, the elution volume has been converted to a slightly different dimensionless parameter, termed relative retention volume (Vr), which is operationally defined as Vr = Vj x scaling factor, where Vr = (V — Vo)/Vo. The Vb is taken as the starting, rather than the apex position, of the BD peak. " The scaling factor normalizes Vr, which may vary slightly from ran to ran due to experimental background variations, by setting the Vr value of pNP to 2 (since the Vr value of pNP eluted from a 2.5 x 100 cm column packed with Sephadex G-lOO with aqueous 0.1 M NaOH is close to 2). Thus, an equivalent expression is Vr = 2 x (V — Vq)/ (K,np - Vo), where VpNp is the elution volume of... 

Figure 8.26 DJDq through aqueous solutions of (O) 19, (0) 110, and ( ) 510 kDa dextrans of 73 kDa (open points, right scale) and 278 kDa (filled points, left scale) polyethylene oxide probes, based on measurements of Brown and Stilbs(42). Lines represent Eq. 8.2, employing the same parameters for all measurements.

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