Durian-like multi-functional Fe3O4–Au nanoparticles: synthesis, characterization and selective detection of benzidine

Abstract

A novel durian-like multi-functional water soluble Fe₃O₄–Au nanocomposite is fabricated via a facile layer-by-layer technology in which a mercapto-silica shell is utilized as a functional coating on the central Fe₃O₄ nanoparticle cluster. Then gold nanoparticles are loaded onto the surface of Fe₃O₄, stabilized by Au–S chemical bonding. The fabricated nanocomposites inherit excellent physical and chemical properties from their building blocks, simultaneously exhibiting superparamagnetic, surface plasmon resonance and surface enhanced Raman scattering (SERS) active properties. Based on the magnetic separability of the inner Fe₃O₄ nanoparticle clusters and the SERS active properties of the suface gold, a selective detection method for benzidine has been developed for rapid detection and ease of operation with a low detection limit of 0.18 ppm.