Rapid and Quantitative Determination of S-Adenosyl-L-Methionine in the Fermentation Process by Surface-Enhanced Raman Scattering

Abstract

Concentrations of S-Adenosyl-L-Methionine (SAM) in aqueous solution and fermentation liquids were quantitatively determined by surface-enhanced Raman scattering (SERS) and verified by high-pressure liquid chromatography (HPLC). The Ag nanoparticle/silicon nanowire array substrate was fabricated and employed as an active SERS substrate to indirectly measure the SAM concentration. The linear relationship between the integrated intensity of peak centered at ~2920 cm−1 in SERS spectra and the SAM concentration was established, and the limit of detections of SAM concentrations was analyzed to be ~0.1 g/L. The concentration of SAM in real solution could be predicted by the linear relationship and verified by the HPLC detection method. The relative deviations (δ) of the predicted SAM concentration are less than 13% and the correlation coefficient is 0.9998. Rolling-Circle Filter was utilized to subtract fluorescence background and the optimal results were obtained when the radius of the analyzing circle is 650 cm−1.

Collaborative Penalized Least Squares for Background Correction of Multiple Raman Spectra

“…The general procedure of this approach is continually smoothing the spectrum until the background is obtained. Many well-known smoothing filters and their enhancements have been widely used in previous studies for the purpose of iteratively removing peaks and deriving backgrounds in the spectra [ 9 – 12 ]. The drawback of such smoothing algorithms is the difficulty in automating their iterations, although some endeavors have been made on this issue [ 10 , 11 ].…”