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Fabrication of SERS‐Active Substrates using Silver Nanofilm‐Coated Porous Anodic Aluminum Oxide for Detection of Antibiotics
Author(s) -
Chen Jing,
Feng Shaolong,
Gao Fang,
Grant Edward,
Xu Jie,
Wang Shuo,
Huang Qian,
Lu Xiaonan
Publication year - 2015
Publication title -
journal of food science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.772
H-Index - 150
eISSN - 1750-3841
pISSN - 0022-1147
DOI - 10.1111/1750-3841.12825
Subject(s) - raman spectroscopy , materials science , raman scattering , substrate (aquarium) , detection limit , surface plasmon resonance , scanning electron microscope , surface enhanced raman spectroscopy , nanotechnology , analytical chemistry (journal) , chemical engineering , nanoparticle , chemistry , optics , chromatography , composite material , oceanography , physics , engineering , geology
We have developed a silver nanofilm‐coated porous anodic aluminum oxide (AAO) as a surface‐enhanced Raman scattering (SERS)‐active substrate for the detection of trace level of chloramphenicol, a representative antibiotic in food systems. The ordered aluminum template generated during the synthesis of AAO serves as a patterned matrix on which a coated silver film replicates the patterned AAO matrix to form a 2‐dimensional ordered nanostructure. We used atomic force microscopy and scanning electron microscopy images to determine the morphology of this nanosubstrate, and characterized its localized surface plasmon resonance by ultraviolet‐visible reflection. We gauged the SERS effect of this nanosubstrate by confocal micro‐Raman spectroscopy (782‐nm laser), finding a satisfactory and consistent performance with enhancement factors of approximately 2 × 10 4 and a limit of detection for chloramphenicol of 7.5 ppb. We applied principal component analysis to determine the limit of quantification for chloramphenicol of 10 ppb. Using electromagnetic field theory, we developed a detailed mathematical model to explain the mechanism of Raman signal enhancement of this nanosubstrate. With simple sample pretreatment and separation steps, this silver nanofilm‐coated AAO substrate could detect 50 ppb chloramphenicol in milk, indicating good potential as a reliable SERS‐active substrate for rapid detection of chemical contaminants in agricultural and food products.