Fig. 8.

Representative HPLC profile of butanol fraction of Spirulina platensis using analytical C-18 column over the period of acetonitrile. The column was equilibrated with 0·1 % (v/v) trifluoroacetic acid/water at flow rate of 1·0 ml/min. The concentration of the eluting solution was raised using linear gradients from 0 to 20 % acetonitrile over 10 min, to 70 % over 25 min. Details of peaks corresponding to butanol fraction are presented in the chromatogram. UV detection was set at 254 and 360 nm, and 1 mg/ml sample was injected each run. Peaks 1–9 of unknown compounds were detected at different retention times (RT).