Preparation and purification of samples Several sample preparation, pre-purification and clean-up steps are used prior to isolation and/or analysis of natural products.
Initial extraction with low-polarity solvents yields the more lipophilic components, while ethanolic solvents obtain a larger spectrum of non-polar and polar material.
If a more polar solvent is used for the first extraction step subsequent solvent
partition allows a finer division into different polarity fractions.