For this purpose Chromabond C18 polypropylene
columns (500 mg adsorbent, 6 mL, Macherey–Nagel GmbH & Co. KG)
were pre-conditioned with methanol (6 mL) and equilibrated with
ddH2O (6 mL). The sample (5 mL) was slowly passed through the
column, whereby the saponins are retained by the adsorbent.