Mixed Exponential Linear Function

An equation that separates two contributions to log k' was developed by Nahum and Horvâth [39], k' = A eBv + (C + Dx|>) (7)

The symbol ij) defines the water fraction in a binary mixture in the case of lipophilicity measurement by HPLC. For use in TLC, Eq.,(7) has to be formulated as follows:

Calculation of parameters A, B, C, and D by an iterative procedure and setting a|> = 1 (i.e., modifier-free), then gives:

RMw data calculated in this way (= /?Mw. [Ior) are almost identical to those obtained by linear extrapolation [24].

Thus, we conclude that in most cases RMvi, carefully calculated by linear extrapolation, is sufficiently precise. In critical cases the use of Eqs. (8) and (9) is recommended.

0 0

Post a comment