秸秆稀酸水解液的气相色谱／质谱法研究

在秸秆两步稀酸水解工艺中,用气相色谱/质谱(GC/MS)法对其水解液中的单糖成分进行测定,采用2%硼氢化钠的氨溶液将稀酸水解液中的单糖还原成糖醇,然后在甲基咪唑催化剂的作用下和乙酸酐在水相中直接反应生成乙酰化的糖醇,用二氯甲烷萃取后进行GC/MS测定.研究结果表明:秸秆稀酸水解液中有五种单糖,主要是木糖和葡萄糖,其次是阿拉伯糖、半乳糖和少量的甘露糖;利用此方法测定了一批秸秆稀酸水解液,得到了该秸秆稀酸水解过程的最佳的反应时间.该方法可快速、准确测定秸秆稀酸水解液中单糖的浓度,为水解工艺的研究提供一种有效的分析方法.

Studies on the Dilute Acid Hydrolysate of Corn Stover with Gas Chromatography-Mass Spectrometry

The monosaccharide of two-step hydrolyzing corn stover by dilute acid was qualified by gas chromatograpy-mass spectrometry(GC/MS).Monosaccharides were reduced to alditol by 2% sodium borohydride solution with ammonia,and then acetylated by acetic anhydride with N-methyl-imidazole as catalyst in aqueous phase.The products were extracted by methylene chloride and analyzed by GC/MS.Five kinds of monosacchirides in the dilute acid hydrolysate of corn stover have been determined by their retention time and characteristic GC/MS fragmentation patterns.They were xylose,glucose,arabinose,galactose and mannose,and the main kind was xylose and glucose.Optimal reaction time was obtained by analyzing a series of dilute acid hydrolysate of corn stover.This method can be used to quantitatively analyze monosaccharides in the dilute acid hydrolysate of corn stover fast and accurately,which provides an effective way for the research of hydrolysis technology.