Abstract
Upon addition of silver nitrate (precursor) to a solution of tyrosine (reductant) and cetlytrimethylammonium bromide (stabilizer), a transient species appears as the reaction time increases, which is stable for several months. The formation of silver nanoparticle was observed visually by color change (pale yellow to brownish yellow). In order to confirm the nature of the transient species, spectroscopic, kinetic, coagulation, transmission and scanning electron microscopic experiments were carried out. The reaction follows first-order kinetics with respect to [tyrosine] and [Ag(+)] under our experimental conditions. The phenolic -OH group of tyrosine is responsible for the reduction of Ag(+) ions. On the basis of various observations, the most plausible mechanism is proposed and discussed.