Facile all-in-one detection of nitrofurantoin in feed and milk by magnetic separation assisted differential pulse voltammetry

Nitrofurantoin (NFT) residue in animal-derived food poses a threat to human health. We proposed a novel strategy for NFT determination in feed and milk, which connected pretreatment technology to electrochemical detection. Cobalt nanoparticles encapsulated in nitrogen-doped carbon nanostructure with carbon nanotubes (Co/N-CNS-CNTs) were prepared for modifying magnetic electrodes. Meanwhile, magnetic reduced graphene oxide wrapped in phenyl-functionalized mesoporous silica (MG@mSiO 2 -Phe) was synthesized as magnetic solid-phase extraction (MSPE) adsorbent. The modified magnetic electrode can gather NFT-adsorbed MSPE materials and then detect NFT via differential pulse voltammetry (DPV) without elution and solution transfer procedures. Both analyte enrichment by MG@mSiO 2 -Phe and signal amplification by Co/N-CNS-CNTs synergistically improved detection sensitivity with slope of calibration curve and limit of detection of 1.365 μA (μmol L −1 ) −1 and 6 nmol L −1 , respectively. In actual samples, this method exhibits higher accuracy and reliability compared with direct DPV detection, and simpler operation process compared with liquid-chromatography method.