微波消解-气相色谱法测定沉积物中的木质素

改进了由Hedges和Ertel建立的沉积物样品中木质素碱性氧化铜氧化分解方法,研究了利用微波加热辅助氧化铜氧化分解沉积物中的木质素,然后用气相色谱法分离测定其单体分子。考察了温度和微波消解时间对木质素消解效率的影响,实验表明在150℃下消解90 min达到最高效率;建立的方法对沉积物中木质素各单体分子分析的加标回收率为91.4%～108%,平均相对标准偏差(RSD,n=5)为4.5%。改进的方法便于控制反应条件,提高分析效率,是较理想的沉积物样品中木质素组成分析的方法。

Gas Chromatographic Determination of Lignin in Sediment Samples Assisted with Microwave Digestion

Sample decomposition method with alkaline CuO oxidation procedure in determination of lignin in sediment samples,firstly developed by Hedges and Ertel in 1982,has been improved.Sediment samples were decomposed with oxidative-alkaline CuO in a microwave-assisted digestion system and then lignin monomers were determined by gas chromatography.The factors affecting the oxidative decomposition efficiency of the lignin,such as digestion temperature and time,were investigated.The experiment results indicated that the best decomposition condition was 150℃ for 90 min.Under the optimized condition,recovery for lignin monomers was 91.4%～108% with average precision of 4.5%RSD.The proposed method provides the advantages of high efficiency,convenient for reaction condition control and has been proved to be an ideal method for the determination of lignin monomers in sediment samples.