激光拉曼光谱内标法直接测定甲醇浓度

Direct Quantitative Determination of Methanol by Laser Raman Spectrometry with Internal Standard Method

利用甲醇溶液中的CH3对称伸缩峰（2843cm^-1）的激光拉曼光谱峰，同时以本底溶液水为内标物，组成相对强度，对溶液中的甲醇含量进行了测定研究，建立了激光拉曼光谱直接法测定甲醇含量的方法，其线性范围为5％40％，线性相关系数为0．9966，检出限为0．29％。并对模拟样品和制备液相色谱待回收废液进行了甲醇浓度的测定，其浓度分别为13．7％、9．41％和58．8％，RSD分别为0．78％、0．75％和1．34％。该方法简单、操作方便，无需添加其它任何化学试剂等优点。

The concentration of methanol solution was determined by internal standard-laser Raman spectrometry. The conditions of laser raman spectrometer are as follows： the laser source is He-Ne 632. 81 nm, 17 mw; the grating number is 600 lp/mm; the confocal aperture is 300 μm; the objective is 50 times long focus lens. Good linear correlation between the intensity ratios of the 2843 cm^-1 （the CH3 stretching band of methanol） to the 3402 cm^-1（band of water） and concentration of methanol was obtained. The linear ranger of methanol concentration is 5% -40% , the correlation coefficient is 0. 9966, and the limit of detection of methanol is 0.29%. The concentration of two simulating samples and the recovered waste liquid of preparative liquid chromatography was determined, the average concentration was 13.7% , 9.4% and 58.8% , and the RSD is 0.8% ,0.8% and 1.3% , respectively. Non-destructive, non-intrusive nature of the method makes the internal standard-laser Raman spectrometry as a convenience, accurate, green quantitative analytical method.