Effect of mobile-phase additives on separation of gold nanoparticles by size-exclusion chromatography

Two spherical gold nanoparticles (diameters 5.3 and 38 nm, respectively) were used to appraise the separation performance of various mobile-phase additives in size-exclusion chromatography (SEC). The three additives were sodium citrate (SC), sodium chloride (NaCl), and sodium dodecylsulfate (SDS). The problem of adsorption on gold nanoparticles occurs when SC and NaCl are used as mobile-phase additives. In contrast, the adsorption problem is overcome by using SDS as mobile-phase additive; furthermore, SDS prevents gold nanoparticles from coagulating during separation. This paper demonstrates the feasibility of using SDS as mobile-phase additive in SEC for size separation of gold nanoparticles and also demonstrates how SEC may be used to investigate interactions between a mobile-phase additive and gold nanoparticles.