Facile isolation and analysis of sporopollenin exine from bee pollen

We present facile methods to obtain purified sporopollenin exine capsules, and provide mass balances for classical and novel purification procedures. An ionic liquid, tetrabutyl phosphonium hydroxide turned out to be the most effective in removing the intine wall. The sporopollenin capsules were investigated by fluorescent microscopy, AFM, solid-state NMR and infrared Raman spectroscopy. The latter two methods showed that sunflower and rape exines have different proportions of O-aliphatic and aromatic constituents. Purified exine capsules were coated with functionalized fluorophores. The procedures presented in this paper could contribute to further spread of the applications of this hollow, and chemically highly resistant material.

Automated summary

The paper presents facile methods to obtain purified sporopollenin exine capsules and provides mass balances for classical and novel purification procedures. It is found that an ionic liquid, tetrabutyl phosphonium hydroxide, is the most effective in removing the intine wall. Various methods were used to investigate the sporopollenin capsules, revealing differences in O-aliphatic and aromatic constituents between sunflower and rape exines.