Aqueous solution (1 mM) of silver nitrate (AgNO3) was prepared
and used for the synthesis of silver nanoparticles. 5 ml
of mangosteen leaf extract was added into 95 ml of aqueous
solution of 1 mM silver nitrate for reduction into Ag+ ions.
In a typical synthesis of silver (Ag) nanoparticles the leaf
extract (1.5 ml) was added to 30 ml of 103 MAgNO3 aqueous
solution in a 250-ml Erlenmeyer flask and heated on water
bath at 75 C for 60 min. Reduction of silver nitrate to silver
ions was confirmed by the color change from colorless to
brown. The formation of silver nanoparticles was also confirmed
by spectrophotometric determination. The fully reduced
solution was centrifuged at 5000 rpm for 30 min. The
supernatant liquid was discarded and the pellet obtained was
redispersed in deionized water. The centrifugation process
was repeated two to three times to wash off any absorbed substances
on the surface of the silver nanoparticles.