A novel approach for the homogenization of cellulose to use micro-amounts for stable isotope analyses
A novel approach for the homogenization of cellulose to use micro-amounts for stable isotope analyses
复制标题
DOI：
10.1002/rcm.4105
复制
发表时间：
2009-07-01
影响因子：
2
通讯作者：
Wissel, H.
中科院分区：
文献类型：
--
作者：
Laumer, W.;Andreu, L.;Wissel, H.
使用树木年轮稳定同位素进行的气候重建正在稳步增加。由于纤维素具有高稳定性，因此研究主要集中在纤维素上。近年来，纤维素的可用量稳步下降，主要是因为必须分析植物材料的微观结构。如今，所研究的纤维素量通常以毫克为单位，并且通常在微克范围内。因此，来自纤维素的碳和氧的稳定同位素出现了均质性问题，并且这些问题需要新的方法来制备纤维素以进行可靠的同位素分析。测试了三种不同的方法来制备同位素均质纤维素，即机械研磨、液氮冷冻随后研磨以及纤维素纤维的超声波破碎。通过冷冻研磨和超声波破碎实现了同位素数据的最佳精度。然而，用于冷冻研磨的设备昂贵并且该过程是劳动密集型的。机械研磨导致材料损失相当高，而且劳动强度大。就样品通量的快速性、避免样品损失、同位素结果的精确性、易于处理和成本而言，使用超声波断裂纤维素纤维被证明是最佳方法。版权所有 (C) 2009 John Wiley & Sons, Ltd.
Climate reconstructions using stable isotopes from tree-rings are steadily increasing. The investigations concentrate mostly on cellulose due to its high stability. In recent years the available amount of cellulose has steadily decreased, mainly because micro-structures of plant material have had to be analyzed. Today, the amounts of cellulose being studied are frequently in the milligram and often in the microgram range. Consequently, homogeneity problems with regard to the stable isotopes of carbon and oxygen from cellulose have occurred and these have called for new methods in the preparation of cellulose for reliable isotope analyses. Three different methods were tested for preparing isotopically homogenous cellulose, namely mechanical grinding, freezing by liquid nitrogen with subsequent milling and ultrasonic breaking of cellulose fibres. The best precision of isotope data was achieved by freeze-milling and ultrasonic breaking. However, equipment for freeze-milling is expensive and the procedure is labour-intensive. Mechanical grinding resulted in a rather high loss of material and it is also tabour-intensive. The use of ultrasound for breaking cellulose fibres proved to be the best method in terms of rapidity of sample throughput, avoidance of sample loss, precision of isotope results, ease of handling, and cost. Copyright (C) 2009 John Wiley & Sons, Ltd.