Individual sample preparation in reference to the compounds and matrix (Adjust pH value if necessary)

Column conditioning: 5 mL methanol, then 5 mL water (Do not let run the column dry!)

Sample aspiration: The prepared sample is passed through the column by vacuum or pressure

Washing 1: 2 mL 0.1 M HCl in water

Washing 2 / Elution 1: 2 mL methanol (elution of neutral and acidic compounds)

Drying: With nitrogen or air

Elution 2: 5 mL methanol / 5 % NH3 (elution of basic compounds)

Evaporation and reconstitution (if necessary)