Surfactant−free synthesis of flower−like Au NPs/Au island hybrid substrate for quantitative SERS detection of pesticide residues on fruit

Abstract

Surface enhanced Raman scattering (SERS) has been extensively applied in the field of biochemical detection ascribed to its high sensitivity and nondestructive pattern. Nevertheless, the further improvement of such attractive protocol is severely hindered by the absence of enough surface roughness as well as the presence of organic surfactant. Herein, we demonstrated a highly sensitive and robust SERS hybrid substrate composed of plasmonic flower−like Au nanoparticles (FANPs)/Au island with clean surface. The development of this novel FANPs architecture could be attributed to the drastic reduction of Au 3+ ions, which triggered the overgrowth of Au atoms in the absence of surfactant. Meanwhile, the pre-existent Au monolayer on the silicon matrix were found to synchronously grew to Au islands, resulting in the formation of hybrid substrates. The FANPs/Au island hybrid substrate performed satisfactorily while monitoring 4 −mercaptobenzoic acid and gave out an excellent enhancement factor of 6.74 × 10 6 . Particularly, the high sensitivity makes the hybrid substrate a fascinating platform for practical monitoring. In this regard, the in−situ detection of thiabendazole on apple was conducted and a limit of detection low to 8.3 ng/mL was achieved. This high−performance SERS substrate provides more opportunities for appreciable in−situ assay in some practical fields. • A plasmonic flower−like Au NPs (FANPs)/Au island with clean surface was constructed without any surfactant. • An excellent enhancement factor as high as 6.74 × 10 6 was achieved by the FANPs/Au island hybrid substrate. • The in−situ detection of thiabendazole on apple was conducted and the limit of detection was achieved as low as 8.3 ng/mL.