Editing Partition coefficient (section)

=== HPLC-based ===
A faster method of log ''P'' determination makes use of [[high-performance liquid chromatography]]. The log ''P'' of a solute can be determined by [[correlation|correlating]] its [[retention time]] with similar compounds with known log ''P'' values.<ref name="pmid15214672">{{cite journal | vauthors = Valkó K | title = Application of high-performance liquid chromatography based measurements of lipophilicity to model biological distribution | journal = Journal of Chromatography A | volume = 1037 | issue = 1–2 | pages = 299–310 | date = May 2004 | pmid = 15214672 | doi = 10.1016/j.chroma.2003.10.084 }}</ref>

An advantage of this method is that it is fast (5–20 minutes per sample). However, since the value of log ''P'' is determined by [[linear regression]], several compounds with similar structures must have known log ''P'' values, and extrapolation from one chemical class to another—applying a regression equation derived from one chemical class to a second one—may not be reliable, since each chemical classes will have its characteristic [[parameter|regression parameters]].{{citation needed|date=March 2016}}