The upper hexane layers were
removed to the tube B and the volume was filled up to 20 ml with
n-hexane/BHT 0.05%. For HPLC analysis, 100 ll of this sample was
evaporated to dry (Techne sample concentrator, model FDB03OD,
Camlab Ltd, Cambridge, UK) and then re-dissolved in 200 ll iso -propanol for HPLC injection.