Nitrilotriacetic acid: A novel reducing agent for synthesizing colloidal gold.

Highlights: [•] Stable gold sols were prepared by reducing [AuCl4]− with nitrilotriacetic acid (NTA). [•] The concentration of reductant dictates the size of gold nanoparticles. [•] A large NTA excess is necessary to prevent the aggregation of Au nanoparticles. [•] Stable sols with a concentration up to 1.5×10−3 moldm−3 have been prepared. [ABSTRACT FROM AUTHOR]