Tunable Plasmonics of Hollow Raspberry-like Nanogold for Robust Raman Scattering Detection of Antibiotic on Portable Raman Spectrometer
It is an important issue to develop novel sensors for simple, rapid, and quantitative detection of the residual antibiotics in food considering the potential threats on human health. Herein we report the successful fabrication of raspberry-like nanogold (R-like Au) structures with rough surfaces and partially hollow structures for the rapid and sensitive detection of antibiotic in duck meats on a portable Raman spectrometer. The R-like Au with tunable plasmonic wavelengths is fabricated by a two-step method. Ag particles as seeds are substituted by Au particles through a replacement reaction, moreover, the surface plasmon resonances (SPR) of R-like Au shift red with the increase of the Au irons concentrations. The R-like Au with a diameter of about 120 nm well matching the 785 nm laser on the portable Raman spectrometers is used as excellent surface-enhanced Raman spectroscopy (SERS) active platform for detecting two kinds of antibiotic, i.e. nitrofurantoin (NFT) and nitrofurazone (NFZ), in spiked duck meats. Both of them have the sufficient sensitivity (0.05−10 mg /L), the good liner relationship (R2 > 0.99) and the high recovery in quantitative SERS spectral analysis. The platform is simple without the need of complex pretreatment of the food samples or using large scale Raman spectrometers, promising the easy implementation for an in-field analyzer on the residual of antibiotics in food.