This study uses AFFF to efficiently separate electrostatically assembled C/S particles from unbound, monomeric gold nanoparticles added in excess during synthesis. Separation efficiency is evaluated using the three quality criteria mentioned above. We will demonstrate why AFFF is superior to conventional centrifugation and quantify how purification of C/S particles improves the colloid's SERS activity. Finally, we also discuss the limitations of salt-based mobile phases for electrostatically assembled particles.