silicagel micro-columns were prepared using 22 cm glass Pasteur pipettes. A glass wool plug was inserted and the
column dry packed with 0.5 and 0.75 g of adsorbent.Columns were rinsed with 10 ml of hexane prior to loading of the sample extract. Columns were eluted with 10 ml of 10% methanol/DCM and collected as one fraction. Rotary evaporation of fractions containing methanol were facilitated with the addition of 10 ml of acetone and 2 ml of isooctane as keeper. Fractions were concentrated to 3 ml by rotary evaporation. Water and sediment fractions were quantitatively transferred with hexane to test tubes and further concentrated to a final volume of 1.0 ml under nitrogen. Biota fractions werequant