小檗碱在TLC原位的FT-SERS研究

应用表面增强技术将薄层色谱与近红外傅里叶变换拉曼光谱联用，获得了中成药三黄片中主要有效成分小檗碱在薄层原位的傅里叶变换表面增强拉曼光谱（FT－SERS）。研究表明，在薄层原位约2.5μm样品的FT－SERS与纯固体样品的FT－Raman光谱的主要特征峰波数基本一致，相对强度有一定变化，出现特别增强的拉曼峰是波数为727nm的芳香环上CH键面内变形振动峰。小檗碱分子以异喹啉环共轭体系的π电子与表面增强活性物质银晶体微粒相互作用，呈平面吸附样式。获得了中成药三黄片中主要有效成分小檗碱分离与高灵敏度指纹检测的可靠的新方法。

In Situ Thin Layer Chromatography-fourier Transform-surface-enhanced Raman Spectrum Study on Ingredients of Berberine

Surface Enhanced Raman Scattering (SERS) combined with Thin Layer Chromatography (TLC) has been used for studying characteristic spectrum of molecules in situ in micrograms samples. There are very few report for applying the SERS-TCL method in the study of the effective ingredients of Chinese traditional herbs. Coptis Chinensis France is an often-used clinic Chinese traditional medicine. Its main effective components include berberine and so on, which have antibiotic very wide and also have curative effect on improving the functions of heart vascular cycles. Therefore the concentrations of berberine are very important for the quality control of the medicine. In this work, the ethanol extract of Coptis Chinensis France was first separated by TLC, the SERS was then measure directly after dropping silver gel on the separated spots. The method can be used for the finger print analysis of the berberine. 3 microL of alcohol extract of Coptis Chinensis France with total alkaloids concentration of 1.0 mg.mL was placed on silicon GF254 TLC plate. The sample was separated by developing solvent of n bulanol-Acitic acid-H2O (7:2:1 V/V). The positions of berberine in the sample were confirmed by the standard alkaloid solutions. The Rf values for berberine are 0.29. The silver gel was used as surface enhanced substrate and placed on the separated berberine spots. FT-SERS was measured directly by a Nicolet FT-Raman 910 spectrometer. Berberine belong to isoquinoline alkaloids. His structure can be found in reference. The date of spectrum of berberine can be seen that the band at 1,396 cm-1 due to Ar-OCH3 deformation vibrations was greatly enhanced, indicating that the molecule was absorbed on silver gel strongly through lone-pair electron in Ar-OCH3. The ring stretching mode occurring around 1,548 cm-1 represents isoquinoline ring in the molecule. The band at 727 cm-1 due to CH (ring) deformation vibrations was also enhanced.