Raman Scattering Spectral Treatment And Experimental Study Of Rhodamine B

With the improvement of people’s living standard,people pay more and more attention to food safety,which has always been a major concern of the community.One of the major threats to food safety is various illegal additives in food.Raman scattering detection technology generally does not touch the sample,no need of sample pretreatment,with the advantages of rapid and accurate.In this paper,the illegal additive Rhodamine B is as the research object,of which the Raman spectra and the experimental data were obtained by using Raman scattering detection.The main contents of this paper are as follows:1.The Raman spectra enhancement method based on the SERS(surface enhanced Raman spectroscopy)technique in Rhodamine B inspection was researched by experiments.The enhancement effects of Ag and Au reinforcing agent were compared and the result of matching agent addition was also discussed.Then the Raman spectra of different proportion of Ag reinforcing agent,Rhodamine B solution,matching agent were analyzed.The results showed that Ag reinforcing agent on Raman spectra of Rhodamine B was better,and the matching agent could improve the enhancement effect obviously.When the concentration of rhodamine B solution is 0.7 ppm,If the proportion of Ag reinforcing agent,Rhodamine B solution,matching agent was 1:4:1,enhancement effect achieved the best result.2.In the Raman spectral smoothing denoising,the denoising methods of wavelet transform and moving average were carried out on Raman spectra of Rhodamine B.Comparison of SNR and RMSE,the hard threshold of wavelet transform method denoising effect was better.In the Raman spectral baseline correction,according to piecewise polynomial fitting baseline,the method based on segmented cubic spline correction spectral baseline is proposed.Cubic spline function is selected due to the capabilities of the continuous in the first and second derivative.Thus the baseline corrected by this method can not only be fitted,but also connect smoothly.That is to say the signal-to-noise ratio of the Raman spectra is improved.Comparing the least squares fitting baseline,cubic spline fitting the Raman spectral baseline of Rhodamine B were more smooth and accurate,that the baseline correction effect was better.3.The Raman spectral characteristic peak intensity is calculated by the characteristic peak area.Based on the Wasson peak area formula,the rapid calculative method of accumulation the peak intensity is proposed.In view of the Raman spectra quantitative analysis,combined external standard method with multivariate linear regression,the preliminary quantitative analysis of Raman spectra of Rhodamine B were carried out by linear regression of principal component and partial least squares.