Abstract:It is simple and time-efficient to determine the antibiotic residues in animal-derived food using surface enhanced Raman spectroscopy（SERS），but the technology is susceptible to matrix interference and exhibited low sensitivity.In this paper，a highly-sensitive SERS aptasensor for the rapid detection of enrofloxacin was developed by SERS combined with magnetic separation and signal amplification strategy. First of all，the Raman probe 4-MBA@PS@cDNA with signal amplification function was constructed using polystyrene microspheres（PS），4-MBA and complementary DNA（cDNA）. The capture probe MB@Apt was constructed using aptamer（Apt）and magnetic bead（MB）. The 4-MBA@PS@cDNA and MB@Apt were assembled into a composite probe by base complementary pairing. The results showed that there was a good linear relationship between the SERS signal intensity of 4-MBA at the Raman shift of 1 078 cm-1 and the logarithm value of the enrofloxacin concentration in the range of 1-100 nmol/L，and the coefficient of determination was 0.956 6.The detection limit of enrofloxacin was 0.71 nmol/L，the recovery of enrofloxacin in milk and pork was between 86.67% and 128.00%，and the relative standard deviation varied between 0.4% and 1.3%.