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

Table 4

Hansch hydrophobicity parameters and PA retention factors on SP-1.

Acid
Nicotinic	−0.27	0.15
Gallic	0.04	0.91
Syringic	0.07	1.13
Sinapic	0.45	1.29
Vanillic	0	1.33
Sorbic	—	1.35
Caffeic	0.51	1.42
Ferulic	0.40	1.64
-Coumaric	0.36	1.88
Benzoic	—	1.89
Salicylic	0	2.06