Flow field-flow fractionation: a versatile approach for size characterization of α-tocopherol-induced enlargement of gold nanoparticles

Flow field-flow fractionation (FlFFF) was used for size characterization of gold nanoparticles. The measured particle sizes obtained from FlFFF for the commercial 10 nm gold nanoparticle standard and the gold nanoparticles synthesized in the laboratory were in good agreement with those measured by transmission electron microscopy (TEM). Further, the capability of α-tocopherol to induce enlargement of gold nanoparticles by catalysis of the reduction of AuCl₄⁻ by citrate was observed by monitoring the changes in particle size of gold nanoparticles using FlFFF. The effects of α-tocopherol and incubation time on enlargement of the gold nanoparticles were examined. Higher concentrations of α-tocopherol resulted in larger nanoparticles. At fixed α-tocopherol concentration, larger nanoparticles were formed at longer incubation times.