A suspension of 50 g of dried spirulina maxima in 600 mL of acetone is stirred for 24 h at room temperature. The mixture is filtered and the deep green filtrate is concentrated with a rotary evaporator. The oily, brownish-green residue is taken up in a solution of 50 mL of chloroform and 1 mL of acetic acid. The solvent is then stripped off with a rotary evaporator. The dark brown residue is applied to silica gel and purified by column chromatography (silica gel, 20 × 6 cm). The elution is first carried out until removal of the yellow gradient containing carotenoids with petroleum ether-DCM 3:1, petroleum ether-DCM 1:1 and finally with DCM-EtOAc-conc. ammonia water 80:19:1. The pheophytin A is nearly black. The near-black product fractions are combined, the solvent stripped off on a rotary evaporator and the residue dried under high vacuum.
Extraction of chlorophyll A from the spirulina
Removal of the solvent
Extraction of the black layers using column chromatography
The pure product