Rapid detection of aflatoxin B1 in food by surface-enhanced Raman spectroscopy of functionalized photonic crystals
In this study,a functionalized photonic crystal surface-enhanced Raman substrate(PC@AuNPs)was prepared using the vertical evaporation self-assembly method,and a surface-enhanced Raman spectroscopy(SERS)method for the rapid detection of aflatoxin B1(AFB1)in food was established.Fourier-transform infrared spectroscopy(FTIR),UV-Vis absorption spectroscopy,X-ray photoelectron spectroscopy(XPS),and scanning electron microscopy(SEM)were used to characterize the prepared substrates.The activity of the SERS substrate was studied using crystal violet as the probe molecule,with the enhancement factor(EF)for crystal violet and AFB1 being 2.0×107 and 1.2×107,respectively.These values were consistent with the simulated results of electromagnetic field enhancement.Additionally,the Raman spectra of AFB1 predicted by DFT theory had characteristic peaks that matched the experimental spectra.The Raman quantitative peak of AFB1 was selected at 1025.5 cm 1,and the linear equation of the method was I=5947.31gc+24658,with a correlation coefficient of 0.9933,a linear range of 1.0～1.0× 104 μg L-1,and the limit of detection was 0.46 μg L-1.This method was used to detect AFB1 in corn,soybean and vinegar samples,with detected levels of 7.40 μg kg-1 in corn and 15.1 μg kg-1 in soybean,and spiked recoveries ranging from 95.8％to 98.0％.The relative errors were-14％for corn and 4.9％for soybean when the new method was compared with the high-performance liquid chromatography(HPLC)standard method.The new SERS method is sensitive,accurate and reliable,meeting the requirements for the rapid detection of AFB1 in grain samples.
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