Sensitive determination of Norfloxacin in milk based on beta-cyclodextrin functionalized silver nanoparticles SERS substrate

The norfloxacin (NFX) residue in milk will increase human resistance to drugs and pose a threat to public health. In this work, a highly sensitive method for detection of NFX was developed based on surface enhanced Raman spectroscopy (SERS) using beta-cyclodextrin functionalized silver nanoparticles (beta-CDAgNPs) as substrate. The unique spatial size and hydrophilicity of beta-CD on the surface of AgNPs could selectively capture the target molecule (NFX) through some weak interactions, including hydrogen-bond interaction, electrostatic interaction, etc. The interactions were characterized by the UV-Vis absorption spectroscopy, fluorescence spectroscopy, Zeta potential and DLS. The Raman signal of NFX is largely enhanced when anchored by beta-CD on the surface of AgNPs due to SERS effect. Through a series of experiments and analysis, the limit of detection (LOD) in standard solution and spiked milk were calculated to be 3.214 pmol/L and 5.327 nmol/L. The correlation coefficients (R-2) were 0.986 and 0.984, respectively. For milk sample determination of NFX, the recovery was 101.29% to 104.00% with the relative standard deviation (RSD) from 2.986% to 9.136%. To sum up, this developed SERS strategy is sensitive and specific to detect NFX in milk, it has practical application value and prospects. (C) 2022 Elsevier B.V. All rights reserved.

Automated summary

A highly sensitive method based on surface enhanced Raman spectroscopy (SERS) was developed for the detection of norfloxacin (NFX) residue in milk. The method utilized beta-cyclodextrin functionalized silver nanoparticles as substrate to selectively capture the target molecule through weak interactions. The experiments showed that the method had a high detection sensitivity and specificity, with good recovery and reliability for NFX detection.