Surface initiated encapsulation of MOF-74 (Ni) on magnetic prickly-like nickel rods combined with silver nanoparticle decoration for simultaneous and selective surface-enhanced Raman spectroscopy analysis of T-2 and deoxynivalenol

Abstract

Herein, Ag nanoparticles decorated MOF-74 (Ni) encapsulated magnetic prickly-like nickel rods (NiRs@MOF-74 (Ni)/Ag) was firstly designed and fabricated for simultaneous surface-enhanced Raman spectroscopy (SERS) analysis of mycotoxins in food samples. The prickly-like NiRs not only provide magnetism with anisotropy structure, but also directly supply Ni2+ for surface initiated encapsulation of MOF-74 (Ni) on NiRs. The as-fabricated NiRs@MOF-74 (Ni)/Ag exhibits good SERS activity due to the enrichment effect of magnetic NiRs, adsorption of MOF-74 (Ni) and localized surface plasmon resonance properties of AgNPs. The enhancement factor for 5,5′-dithiobis-(2-nitrobenzoic acid) and 4-mercaptobenzoic acid can reach 108 level with limits of detection (LOD) of 1.0 ng/L. Subsequently, the magnetic aptamer probes based on NiRs@MOF-74 (Ni)/Ag were fabricated for simultaneous, sensitive and selective SERS analysis of T-2 and deoxynivalenol in food samples. The method exhibited satisfactory linearity in range of 0.5–750.0 μg/L and 0.3–750.0 μg/L with LOD of 0.15 and 0.08 μg/L for T-2 and deoxynivalenol, respectively. The relative errors between the developed method and standard HPLC-MS ranged from −7.7 to 1.4%. Our results open a new venue in design and fabrication of magnetic SERS substrates with unique property for quantification of multiple mycotoxins in complex samples.