The high enhancement activity of litchi-like gold nanoparticles (Au NPs) is prepared in deep eutectic solvent (DES), and the prepared Au NPs as SERS active substrate exhibits excellent sensitivity when rhodamine 6G (R6G) is used as a probe molecule for detection. The enhancement factor (EF) is calculated to be about 1.8 × 10¹², and the minimum detected concentration is outstanding in R6G aqueous solution at 10⁻¹² M. In addition, the microtrace determination of penicillin G sodium (PG) in camel milk powder produced in Xinjiang was successfully achieved by using the prepared Au NPs. This work provides an environmentally friendly, simple, and rapid method to prepare efficient and sensitive surface-enhanced Raman scattering (SERS) materials. Meanwhile, it also uncovers a new possibility for the development of various nanoparticles with SERS prepared using DES as reactive solutions.

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