Raman spectroscopy in determination of forsythin content / 第二军医大学学报

ABSTRACT

Objective: To compare the two parameters in Raman spectroscopy quantitative analysis, so as to confirm the optimal one. Methods: The ratios of peak intensity and peak area were taken as parameters in quantitative analysis. The contents of forsythin in forsythia suspense leaves gathered at different time points from different regions were analyzed with laser Raman spectroscopy. When the ratio of the peak intensity was taken as parameter, the Raman peak of forsythin (ρΛr-H [1 319.1 cm-1]) and the peak of methanol (νasCH3-O [2 974. 7 cm-1]) were selected as quantitative peak and internal standard reference peak in the confocal micro-Raman spectra of forsythin methanol solution. When the ratio of the peak area was taken as parameter, the Raman peak of forsythin ( ρΛr-H [1 319.1 cm-1]) and the peak of methanol (νsCH3-O[3 020. 9 cm-1]) were selected. The ratios of intensity and area were taken as ordinate, and the content of forsythin was taken as abscissa. The two standard curves were plotted and the linear and recoveries were compared. Results: Both parameters had good linear relationship with forsythin concentration, with the correlation coefficients being 0.998 0 and 0.997 6; the recoveries were 100.04%-101.30% and the recycling was complete. The linear fitting of the results with two parameters were measured, and the regression equation was C2=1.030 4C 1=0.033 1, r=0.999 6. The results obtained with the two parameters were accurate and were largely identical. Conclusion: Both the relative peak intensity and the ratio of the peak area can be used as parameters for forsythin quantitative analysis with Raman spectroscopy. And the two parameters can obtain largely identical results. Raman spectroscopy with internal standard is a simple and rapid method for quantitative analysis of forsythin, and it can be used for quantitative analysis for Chinese herbs.