薄层原位表面增强拉曼光谱法检测中成药和保健品中添加的西地那非

Determination of sildenafil citrate added in traditional Chinese medicines and health care products by thin layer chromatographic surface-enhanced Raman spectroscopic method

目的:考察西地那非在薄层原位表面增强拉曼光谱(TLC-SERS)的特点及其影响因素,并建立中成药和保健品中添加西地那非的薄层原位表面增强拉曼光谱的检测方法。方法:比较了西地那非拉曼光谱及其薄层原位表面增强拉曼光谱的差异,考察了激光光源强度、测定积分时间、纳米银溶胶溶液用量、西地那非浓度及空白硅胶等因素对西地那非薄层原位表面增强拉曼光谱的影响;将3种具有壮阳作用的中成药进行薄层色谱分离后,对与西地那非Rf值一致的斑点进行原位表面增强后测定其拉曼光谱,并通过与西地那非对照品薄层原位表面增强拉曼光谱进行比较,来进一步判断中成药和保健品中是否含有西地那非。结果:薄层原位表面增强后的拉曼光谱与西地那非的拉曼光谱比较除1582 cm-1处拉曼峰的位置没有变化外,在1563、1530、1405、1240、1272 cm-1处的拉曼峰位置发生了蓝移和红移,个别峰的强度也发生了变化,但主要特征谱带的形状和频率基本保持一致。随着激光强度的增大、积分时间的延长、纳米银溶胶用量的加大及西地那非浓度的增加,西地那非薄层原位表面增强后的拉曼光谱的强度都会相应加大,并且空白硅胶的表面增强拉曼光谱对其没有影响。经薄层色谱分离后在与西地那非Rf值一致的斑点测定的原位表面增强拉曼光谱与西地那非斑点的表面增强拉曼光谱的光谱特征非常一致。结论:将薄层的分离作用与表面增强拉曼光谱结合,可以快速确认薄层色谱上的疑似斑点是否为西地那非成分。薄层原位表面增强拉曼光谱法可作为中成药及保健品中添加西地那非的检测方法。

Objective： To investigate the characteristics and influencing factors of sildenafil in the thin layers chromatographic surface- enhanced Raman spectroscopy（ TLC- SERS）,and to establish a detection method for sildenafil adulterated in traditional Chinese medicine and health products with TLC- SERS. Methods： The difference between the normal Raman spectrum and the enhanced spectrum with TLC- SERS was compared. Some factors on the Raman spectrum through TLC- SERS including laser light source intensity,determination of integration time,dosage of nanometer silver sol solution,concentration of sildenafil and blank silicone were investigated. Three types of traditional Chinese medicine samples with the aphrodisiac effect and reference standard sidenafil were separated through TLC. After separation,we focused the spot which has the similar Rf value with the reference standard and collected the enhanced Raman spectrum. Meanwhile,we compared the separated spectra with the spectrum in situ,so as to detect whether the traditional Chinese medicine and health products were adulterated with sidenafil.Results： Due to the interaction between molecules and the nanosize silver particles,we compared the enhanced spectrum with the normal spectrum. It was found that the peak at 1582 cm- 1did not change,while the position of the peaks at 1563,1530,1405,1240 and 1272 cm- 1emerged blue shift and red shift; the individual peak intensity was also changed,but the shape and frequency of the main characteristics band remained the same. With the increase of laser intensity,nano silver sol dosage,the concentration of sildenafil,and the extension of integration time,the intensity of the enhanced spectrum increased accordingly; moreover,the enhanced spectrum on blank silicone caused little influence. After separation through thin layer chromatography,the result of the spot which has the same Rf value with the reference standard sidenafil in samples was consistent with that of the spot of pure reference standard sidenafil. Conclusion： Combining the thin layer with the separation effect and surface- enhanced Raman spectroscopy,it can be rapidly identified whether these suspected spots on thin layer chromatography are the substance sildenafil. The established TLC- SERS method can be used to detect whether traditional Chinese medicine and health products are adulterated with sidenafil.