2D-TLC of caffeic acid in propolis sample from Peruča and standards of caffeic acid. The plate was first developed in the direction 1 then 2 using mobile phase 1 (n-hexane : ethyl acetate : glacial acetic acid = 31 : 14 : 5 v/v) and mobile phase 2 (chloroform : methanol : formic acid = 44 : 3.5 : 2.5 v/v). Bands were visualized under short and long wave UV light and under long wave UV light after spraying with 1% AlCl3 ethanol solution. Concetration obtained from chromatograms: a = mmax = 2.50 μg, b = mmin = 0.83 μg, c = mmid = 1.67 μg, PS = mpropolis sample = 2.91 μg .
Medić-Šarić et al. Nutrition Journal 2009 8:33 doi:10.1186/1475-2891-8-33