Two grams of carrot or tomato puree were accurately weighed out into 50-
mL screw-top glass centrifuge tubes. The samples were thoroughly homogenized
with 10 mL of methanol and left for 15 min until the aqueous domains were
fully equilibrated with the methanol. The samples were again thoroughly homogenized
after adding 10 mL of chloroform and vigorously shaken with 10 mL
of water. Hydrolyzed samples were then extracted three times with chloroform,
evaporated under nitrogen, and resuspended in 1 mL of dichloromethane and 9
mL of HPLC mobile phase.