Fig. 1From: The pH-Dependent Stucture and Properties of Au and Ag Nanoparticles Produced by Tryptophan ReductionThe color of gold colloids obtained from initial reagents used at different pH. Tryptophan was used in cationic (acidic medium, рН = 2), neutral (neutral medium, рН = 6), and anionic (alkaline medium, рН = 10) forms. HAuCl4 had initial pH = 2, 4, and 6Back to article page