Batch adsorption isotherms (6 points in triplicate with 4
blanks) from water were prepared with an initial concentration
of 1 μg AfB1/mL in 5-mL aqueous dispersions. The aqueous
dispersions contained 10 to 180 μg of clay or activated carbon
in 15-mL polypropylene centrifuge tubes. A stock solution
containing 100 μg AfB1/mL in acetonitrile solution was
prepared. Aliquots of acetonitrile stock solution were diluted
with water and used to deliver aflatoxin to isotherm solutions
(50 μL stock+0.95 mL of water=5 μg AfB1/mL). Blanks
containing only AfB1 and water were prepared. The samples
were thoroughly mixed using a vortex mixer. After overnight
agitation on a reciprocating shaker, the tubes were centrifuged,
and the supernatants were passed through 0.2-μm filters and
collected in 20-mL plastic vials.