固相萃取-气相色谱法测定土壤中木质素

Determination of lignin in soil by solid phase extraction/gas chromatography

建立了固相萃取-气相色谱法测定土壤中木质素的方法。采用碱性氧化铜法水解木质素聚合物,水解产生的木质素酚类单体通过固相萃取小柱后用乙酸乙酯洗脱,用双(三甲基甲硅烷基)三氟乙酰胺(BSTFA)衍生。在水解前加入乙基香草醛作为内标物来定量木质素衍生的单体。木质素的含量用8种木质素单体的总和来表征。该方法的平均回收率为83%～112%,相对标准偏差为4.4%～6.2%。在0.05～5.00mg/mL范围内,各木质素单体的质量浓度与峰面积呈良好的线性关系,相关系数均大于0.999。该方法定量准确,精密度高,可有效消除因实验操作和仪器波动等引起的测定误差,尤其适用于土壤等复杂样品的分析。

A method was established for the determination of lignin in soil by solid phase extraction/gas chromatography （SPE/GC）.The lignin polymers were hydrolyzed by alkaline CuO oxidation method.The products lignin-derived phenol monomers were passed through a solid phase extraction cartridge,and after eluted with ethyl acetate,the lignin monomers were derivatized by N,O-bis（trimethylsilyl） trifluoro-acetamide. Before hydrolysis,ethylvanillin was added as internal standard for quantification.The content of lignin in soil was represented by the sum of eight lignin-derived monomers.The average recoveries of eight lignin-derived monomers ranged from 83%to 112%with RSDs of 4.4%～6.2%.There was a good linearity in the range of 0.05～5.00mg/mL（r=0.999）.The method is accurate and precise,and can eliminate operational errors.It is suitable for the analysis of complex samples such as soil samples.