How do you extract isoflavones from soybeans?

Journal of Chromatography A, 1076 (2005) 110–117

Sample pretreatment: Add 250 mL of 50% ethanol to 10g of ground soybeans.  Stir for 30 minutes at 60 °C.  Centrifuge extract, filter, and freeze dry.  Store resulting fine powder at -32 °C.

To a 200 mg Strata-X cartridge,

Condition/equilibrate with 2 mL methanol and 2 mL deionized water

Load 0.1 g of powder obtained previously dissolved in 25 mL deionized water

Wash with 2 mL deionized water

Dry cartridge under vacuum for 10 minutes

Elute with 2x 2 mL methanol