SERS fingerprinting detection of ochratoxin A on molecularly imprinted magnetic inverse photonic crystals.

Raman Fingerprinting spectra detection of ochratoxin A (OTA) in food still meets serious challenge because of uncontrolled signal heterogeneity and poor reproducibility at low analyte concentrations. Here, OTA molecularly imprinted three-dimensional (3D) porous SERS substrate was prepared on the surfaces of magnetic inverse photonic crystal microspheres (MIPCMs) @AuNPs, and its Raman analytical enhancement factor can reach to 2.67 × 10. The OTA imprinted polymer was synthesized using 3-aminopropyltriethoxysilane and phenyltriethoxysilane as the dual-functional monomers and Fmoc-d-Phenylalanine as the template molecule on the surfaces of MIPCMs. The functional microspheres can specifically enrich OTA and remarkably enhance the fingerprint Raman spectrum of OTA. The label-free 3D SERS substrate can rapidly quantitatively detect OTA by its fingerprint Raman spectrum, which shows a linear detection range of 10 to 10 ng/mL, a limit of detection of 0.078 ng/mL, good recovery rates of 76-97 % and regeneration property. The developed SERS method can integrate enrichment and detection of OTA in one system, which has a great application prospect in simple, rapid and high sensitivity detection of OTA.