Flexible graphene oxide/Ag SERS substrate and its applications for ultrasensitive detection of florfenicol residues in milk

Extensively employed antibiotics in livestock cause residue in food products that would threaten public health safety. In this work, we have developed a flexible, sensitive, cost-effective graphene oxide (GO)/silver–polyester fibrous membrane (PFM) flexible SERS substrate (GO–Ag–PFM) which is suitable for in situ food safety detection. PFMs built nanoporous networks as a flexible template, while GO–Ag nanomaterials were precipitated on the crossed fibers by self-assembly techniques, providing a density “hot-spot” that significantly increased electromagnetic fields. The lowest distinguishable level of rhodamine 6G is 10 −9 mol/L, and the flexible SERS substrates also exhibit good uniformity and reproducibility. The sensitive GO–Ag–PFM flexible SERS substrates achieve low-level SERS detection of florfenicol (FF). The estimated LOD is low to 2.46 × 10 −9 mol/L for FF. The proposed method can be applied to the determination of FF residues in milk. The recoveries were 89–98% with a relative standard deviation of 4.5–9.1%, which is expected to show great potential in food safety testing.