Figure 3.
Isocratic log k vs. solvent composition for the 19 test compounds. These include N,N-diethylacetamide (
), N-allyl aniline (
), 1,3-naphthalenediol (
), diphenylamine (
), 7-amino-4-methylcoumarin (
), naphthalene acetamide (
), 2-phenylindole (
), anilinoacetaldehyde diethyl acetal (
), tetrabutylammonium (
), abscisic acid (
), tetrapentylammonium (
), prednisone (
), cortisone (
), hydrocortisone (
), curcumin (
), chlorogenic acid (
), p-coumaric acid (
), dodecanophenone (
), and di-n-pentyl phthalate (
). Though the relationships are difficult to distinguish, one can see that they cover a wide range in retention and that the relationships do not generally run parallel to one another as is assumed in linear retention indexing.