The correlation between the Raman stretching frequency shifts of a ethyl group and the concentration of the ethanol in aqueous solution was studied, and the new methods to determine the ethanol content in aqueous solution were obtained. The Raman spectra in the range of 500～4 000 cm-1 were obtained on the Renishaw 1000 Raman spectrometer in the room temperature,which shows that the shifts of C-H stretching vibration bands give a negative correlation with the ethanol concentration.Furthermore, the simple linear regression was employed to analyze the relation between the shift of band position and the concentration, and then a futher research using Multiple Linear Regression (MLR) was performed to obtain a function between the ethanol concentration and the shifts of bands on the base of this. The results show that for both the C-H symmetric stretching vibration band and the -CH3 asymmetric stretching vibration band, there are significant linear relations between their parameters. In addition, the determination coefficient of the MLR model has reached 0.98, which shows a perfect linear relation. These results indicate that the ethanol concentration in the aqueous solution can be measured by the Raman stretching frequency shifts of ethyl group.%为了进一步探索用激光拉曼光谱测定乙醇水溶液中乙醇浓度的方法,研究了室温下C-H伸缩振动频移与溶液浓度的关系.室温下,在Renishaw 1000型激光拉曼光谱仪上测得了不同浓度乙醇水溶液在500～4 000 cm-1的拉曼光谱,发现溶液位于2 800～3 050 cm1的3个C-H伸缩振动特征峰的峰值位置相对纯乙醇对应峰位的偏移量大致与乙醇浓度呈线性相关.对各峰峰值位置随浓度变化发生偏移的实验数据进行一元线性回归,然后利用回归结果进一步进行二元线性回归,得到乙醇浓度与C-H伸缩振动频率变化量的回归模型.实验结果表明,C-H对称伸缩振动峰(位于2 882cm1附近)对应的回归方程决定系数为0.962 2.-CH:非对称伸缩振动峰(位于2 977 cm-1附近)对应的回归方程决定系数为0,9650,此二峰的频移量均与浓度呈现出较高的线性相关度,据此建立的二元回归方程决定系数达到0.98.可以用于常温下乙醇浓度的测定.实验研究表明,用激光拉曼光谱中乙醇分子的C-H伸缩振动频移测定室温下乙醇水溶液的浓度是可行的.
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