This study used a confocal Raman microspectrometer produced by Renishaw, Britain, purchased by the Key Laboratory of the School of Optoelectronics and Engineering of Fujian Normal University. The spectral resolution was 2 cm-1, the excitation wavelength was 785 nm, and a 20x objective Leica microscope was used to collect SERS spectra in the range of 400-1800 cm-1. The excitation irradiation time of each spectrum was 1 s, and the laser power was 30 mW. The measured SERS spectra were collected using the WIRE3.4 (Renishaw) software package. In order to reduce the interference of fluorescence background signals between different spectral lines, the Vancouver Raman Algorithm software (multi-order polynomial fitting algorithm) was used to remove the fluorescence background, remove the baseline and smooth the results. At the same time, in order to avoid changes in peak spectrum intensity caused by instrument performance problems, the spectrum after background subtraction was normalized using NILabVIEW2014 software. Then, the obtained spectral data was analyzed for mean spectrum and charts using Origin, and multivariate statistical analysis was performed.
