激光拉曼光谱内标法直接测定乙醇浓度

采用激光拉曼光谱对醇类样品中的乙醇含量进行直接测定。通过不同浓度乙醇的拉曼光谱特征峰(CCO面内伸缩振动884cm-1)与本底水峰组成相对强度比,建立线性回归方程,结果表明,线性范围为4%~40%,线性相关系数为0.9975;检出限为1.02%;回收率为82.0%~105.0%。对白酒、清酒、杨梅酒和医用酒精棉进行了测定,其乙醇平均浓度分别为36.1%、15.5%、23.7%和79.1%;RSD分别为0.22%、1.75%、2.49%和2.76%。此方法具有快速、简便、直接、绿色、对样品无损等优点,适用于白酒类、医用酒精等乙醇含量的检测。

Direct Determination of Ethanol by Laser Raman Spectra with Internal Standard Method

Immediate quantitative analysis of ethanol using internal standard by laser Raman spectra has been studied. Good linear correlation between the intensity ratios of the 884 cm-1 (the CCO band of ethanol) to the 3200 cm-1 (band of water) and concentration of ethanol was obtained. The linear range of ethanol concentration are 4%-40%, the correlation coefficient was 0.9975, the detection limit of ethanol is 1.02%. The method has been used to determine distilled spirit, wikipedia, waxberry vino and alcohol cotton, the results show the alcohol concentration are 36.14%,15.50%,23.71%,79.10%, and the RSD are 0.2%, 1.8%, 2.5% and 2.8%, respectively. Non-destructive, non-intrusive nature of the method makes internal standard-laser Raman spectra as a convenience, accurate quantitative analysis method for ethanol.