Characterization of residual lignins from chemical pulps of spruce (Picea abies L.) and beech (Fagus sylvatica L.) by analytical pyrolysis-gas chromatography/mass spectrometry
Characterization of residual lignins from chemical pulps of spruce (Picea abies L.) and beech (Fagus sylvatica L.) by analytical pyrolysis-gas chromatography/mass spectrometry
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DOI：
10.1515/hf.2001.031
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发表时间：
2001-01-01
期刊：
影响因子：
2.4
通讯作者：
Meier, D
中科院分区：
文献类型：
--
作者：
Choi, JW;Faix, O;Meier, D
通过酶水解从云杉木和山毛榉木获得的亚硫酸盐、牛皮纸、ASAM 和苏打/AQ/MeOH 纸浆中分离出残留木质素。样品的蛋白质含量在2%至61%之间，碳水化合物含量大致在1%至12%之间波动。其中七种分离物已进行分析热解 (Py-GC/MS)，旨在测定以 4-羟基苯基丙烷、愈创木基丙烷和紫丁香基丙烷单元（以下称为 H、G 和 S 单元）表示的木质素组成。蛋白质的热解主要产生苯酚、甲酚和吲哚。蛋白质来源的苯酚和甲酚可能严重影响木质素H含量的测定。然而，蛋白质对该化合物的贡献可以根据热解图中吲哚峰的强度成功校正。然而，对于蛋白质严重污染的样品，热解结果不应过度解释 H 含量。由于分析热解以与化学降解技术类似的方式高估了硫含量，因此使用经验校正方程来近似“真实”硫含量。 Py-GC/MS 一方面给出了残余木质素与另一方面已热解用于比较的 MWL 之间的系统性和可重复性差异。讨论了分析热解的指纹识别能力、打嗝残留木质素的 GIS 比率以及高硫含量 ASAM 残留木质素的异常性质。
Residual lignins have been isolated by enzymatic hydrolysis from sulfite, kraft, ASAM and soda/ AQ/MeOH pulps obtained both of spruce and beech wood. The protein content of the samples were in the range of 2 to 61% and the carbohydrate content fluctuated roughly between 1 and 12%. Seven of the isolates have been submitted to analytical pyrolysis (Py-GC/MS) aiming at the determination of the lignin composition in terms of 4-hydroxy-phenylpropane, guaiacylpropane, and syringylpropane units, referred to in the following as H, G, and S units. Pyrolysis of proteins leads mainly to phenol, cresol, and indole. Phenol and cresol of protein origin may influence seriously the H content determination of lignins. However, the contribution of protein to this compounds can be corrected successfully based on the intensity of the indole peak in the pyrograms. Nevertheless, the pyrolysis results should not be over-interpreted concerning the H contents in the case of samples heavily contaminated with proteins. As analytical pyrolysis overestimates the S content in a similar manner as the chemical degradation techniques do, an empirical correction equation was used to approximate the "true" S content. Py-GC/MS gave systematic and reproducible differences between the residual lignins on the one hand, and the MWLs, which have been pyrolysed for comparison, on the other hand. The fingerprinting ability of analytical pyrolysis, the GIS ratios of belch residual lignins, and the unusual properties of ASAM residual lignins with their high S contents are discussed.