Detection of Triphenylmethane Drugs in Fish Muscle by Surface-Enhanced Raman Spectroscopy Coupled with Au-Ag Core-Shell Nanoparticles

摘要

Silver-coated gold bimetallic nanoparticles were synthesized and used as substrates for surface-enhanced Raman spectroscopy (SERS) in detecting prohibited triphenylmethane drugs (including crystal violet and malachite green) in fish muscle. The optical properties and physical properties of bimetallic nanospheres were characterized by UV-Vis spectroscopy and transmission electron microscopy. The optimal nanospheres selected had relatively uniform size (diameter: 33 ± 3 nm) with a silver layer coated on the surface of gold seed (diameter: 18 ± 2 nm). For both crystal violet and malachite green, characteristic SERS spectral features could be identified at concentration as low as 0.1 μg/L with these bimetallic nanospheres. Crystal violet and malachite green residues in fish muscle could also be detected at levels as low as 0.1 ng/g, which could meet the most restricted regulatory requirements for the limit of detection in terms of analytical methods for crystal violet or malachite green in fish muscle. This study provides a basis for applying SERS technology with bimetallic nanoparticles to the identification of trace amounts of prohibited substances in aquatic food products, and the methodology could be extended to analyses of other hazardous chemicals in complex food matrices like vegetables and meats.