气相色谱法测定粗甘油中的游离甘油含量

摘要

A gas chromatographic method was developed for the determination of free glycerol in crude glycerine without any derivative pretreatment. The sample was resolved with THF -water (3 : 1)mixed solvents using diethylene glycol diethyl ether as internal standard, and was directly separated on an HP-5 column(30 m ×0. 32 mm ×0. 25 μm). The influences of some important, factors, such as solvent , internal standard, capillary column and injection volume were investigated. Under the optimal conditions, the standard curve of glycerol was linear in the concentration range of 0 -20 g/L, with correlation coefficient of 0. 999 94. The relative standard deviations(RSDs, n =8) were in the range of 0. 68% -0. 91% . The spiked recoveries at three concentration levels ranged from 95% to 105% . Neither solvent nor internal standard applied in this method made chemical reaction with the ingredients of crude glycerine sample. This method was simple, rapid and accurate, and was suitable for the quantitative analysis of glycerol content in crude glycerine.%建立了气相色谱法直接测定生物柴油副产物粗甘油中甘油含量的方法.采用四氧呋喃-水(3:1)混合溶剂溶解粗甘油样品,以二乙二醇二乙醚作内标,直接在HP-5柱上进行GC法分离,无需衍生化步骤,内标法定量.对溶剂、内标物、色谱柱、进样量等参数进行了优化,在最佳实验条件下,甘油溶液质量浓度在0～20 g/L范围内线性良好,相关系数为0.999 94.对实际样品进行8次平行测定,相对标准偏差为0.68％ ～0.91％.对样品进行高、中、低3个水平的加标回收实验,回收率在95％～105％之间.该方法所选用的溶剂和内标物均不会和体系中的物质发生化学反应,操作简便、分析快速、结果准确,适用于粗甘油中游离甘油的测定.