六种长链脂肪酸类似物的衰减全反射红外光谱鉴别

Differentiation of Six Long-chain Fatty Acids Analogues by FTIR Fourier Transform Infrared Spectroscopy

利用衰减全反射红外光谱及二阶导数红外光谱对不饱和程度递增的六种长链脂肪酸类似物进行分析鉴别.结果表明,722cm-1附近的4个以上直链-CH2-结构面外摇摆特征吸收峰强度与-CH2-个数成正相关;3 010cm-1附近的稀氢伸缩振动特征吸收峰强度与分子的不饱和程度成正相关.上述规律在二阶导数红外光谱图中变得更加明显,使得仅具细微差异的类似物也可以通过傅里叶变换红外光谱区进行鉴别,从而使红外光谱在类似物鉴别中的应用前景变得更加广阔.

Analogues of six long-chain fatty acids were differentiated by attenuated total reflection Fourier transform infrared spectroscopy and second derivative infrared spectroscopy.These fatty acids had characteristic absorption peaks at 722cm-1 or 3010cm-1,which were attributed to the wagging vibration of four or more -CH2-chain structure or the stretching vibration of(-C=)C-H respectively.The peak intensity at 722cm-1 was positively correlated with the -CH2-numbers and that of the 3 010cm-1 was positively correlated with the unsaturated degree of fatty acid.Much more differences could be found in the second derivative infrared spectra.The results show that even analogues with tiny difference could be discriminated by FTIR technique.Therefore,FTIR method was a promising way for discrimination of structure analogues.