A highly sensitive SERS sensor based on PVDF/Au nanofibers for trace analysis of nitrite ions

Nitrite ions present a significant risk to both environmental and human health, necessitating precise and sensitive detection methods. Herein, we fabricated a highly sensitive SERS sensor based on PVDF/Au nanofibers for nitrite ion detection. The synthesis of PVDF nanofibers involved the utilization of electrospinning apparatus, while the uniformity and high density of SERS activity "hot spots" were achieved by directly coating plasma gold nanoparticles onto the PVDF surface adopting thermal evaporation. The efficient charge transfer of the interface dipole layer directly generated on the surface of PVDF nanofibers was achieved through thermal evaporation. The enhanced Raman responses were due to the combined effects of local surface plasmon resonance of Au nanoparticles and photoelectric and piezoelectric properties of PVDF. It is noteworthy that the prepared SERS substrate exhibited high sensitivity towards rhodamine 6G, boasting an enhancement factor of 9.4 × 10⁷ and a detection limit spanning from 10^-6-10^-11 M. Furthermore, the PVDF/Au membrane functionalized with p-aminothiophenol (PATP) effectively captured NO₂^- ions at concentrations as low as 10^-8 M and successfully detected NO₂^- in river water samples. Additionally, the SERS substrate has good repeatability and stability, and can be applied to trace detection in food safety and medical diagnosis.