HPLC Separation of Phenolic Acids on Silica Gels Layer-by-Layer Modified with 6,10-Ionene and Dextran Sulfate

Table 6

Hansch hydrophobicity parameters and PA retention factors on SP-2.

Acid
Nicotinic	0.03	0.15
Sorbic	0.20	1.35
Benzoic	0.23	1.89
Salicylic	0.64	2.06
Syringic	0.65	1.13
Gallic	0.66	0.91
Vanillic	0.68	1.33
Sinapic	0.85	1.29
-Coumaric	0.94	1.88
Ferulic	0.95	1.64
Caffeic	1.06	1.42