· Silver nitrate is typically impregnated on silica gel (SNIS) or alumina for separation. Several research groups reported the separation of fatty acids on SNIS 59–61]. Wang et al. reported the isolation of zingiberene from ginger oleoresin by SNIS column chromatography . A pair of isomers, brasiliensic acid (83, Fig. 11) and isobrasiliensic acid (84), were separated from Calophyllum ...