顶空气相法测定木质素中甲氧基含量

Determination of Methoxyl Content in Lignin by Headspace Gas Chromatography

关键词:  木质素  甲氧基  顶空气相

Key Words:lignin  methoxyl group  headspace gas chromatography

摘要:本研究介绍了一种顶空气相色谱法快速测定木质素甲氧基含量的方法，并以12种木质素模型化合物验证该方法的准确性和可靠性。在密闭的顶空样品瓶中加入木质素样品和0.5 mL氢碘酸，130℃下反应30 min，随后注入柠檬酸钠溶液中和样品，通过HS-GC测定样品瓶中的碘甲烷含量。结果表明，丙酮抽提后云杉木粉（以Klason木质素计）甲氧基含量为4.6560 mmol/g，以滴定法作为对照测定甲氧基含量为4.6028 mmol/g，两者RSD值＜1%。本方法简便、准确，具有较好的精准度，可用于有效测定木质素及相关物质中甲氧基的含量。

Abstract:A method for rapid determination methoxyl content in lignin by headspace gas chromatography was introduced， and its accuracy and reliability were verified by twelve lignin model compounds. This method included adding lignin sample and 0.5 mL hydroiodic acid into a closed headspace sample vial， reacting at 130℃ for 30 min， then injecting trisodium citrate dihydrate solution to neutralize the sample， and determining the content of iodomethane in the sample vial by HS-GC. The results showed that the methoxyl content of the spruce wood powder extracted with acetone was 4.6560 mmol/g by this method （based on Klason lignin）， and the methoxyl content was 4.6028 mmol/g by titration as the control method with the RSD <1%. This method was simple， accurate and had good precision. It could be used to effectively determine the content of methoxyl in lignin and related substances.