科研之友
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摘要
Microplastics represent an emerging environmental problem worldwide, raising ecological and food safety concerns. Compared to microplastics, there is growing evidence of an even higher abundance of submicro-and nanoplastics in the environment, but a reliable monitoring method for detecting these smaller-sized plastics is lacking. Herein we presented the application of surface-enhanced Raman scattering (SERS) for this purpose. Particles of polystyrene (PS; 600 nm) were used as the probe analyte. Gold nanourchins (AuNU; 50 nm), i.e. urchin-shaped nanoparticles with irregular spikes around the core, were used as the SERS-active substrate. The effectiveness of SERS on PS was evaluated at a single-particle level with different numbers of AuNU in order to determine the minimum conditions required for the onset of the SERS effect. Our findings suggest that SERS of a single particle of PS can be induced by as few as 1-5 particles of AuNU, and that the use of excitation wavelength at 785 nm is appropriate to meet the red-shifted surface plasmon resonance of AuNU upon aggregation. These specifications provide additional information for the development of SERS-based tools for detecting plastic particles < 1 mu m in food and environmental samples.
