Separations were conducted on a Nucleosil 100 C18 column
(250 mm 4.6 mm, 5 mm). The mobile phase consisted of 1%
aqueous acetic acid (eluent A) and methanol (eluent B), and was
based in the method described by Irakli et al. (2012). The linear
gradient started with 90% A, reaching 80% A at 10 min, 75% A at
20 min, 65% A at 30 min and finally 35% A at 40 min