Isotopic fractionation caused by a common cellulose extraction method

In many scientific disciplines, tree rings and wood samples have been valuable resources for establishing chronological conditions of past climate conditions (e.g., rainfall, temperature, humidity) and plant characteristics (e.g., water use efficiency). Stable isotopes have been used as a direct complement and validation of many traditional dendrochronological techniques and have expanded the capabilities and accuracy of tree ring-based methods. Much of the carbon cycling analysis begins by extracting -cellulose from the annual growth rings of a study species. There are many different methods for extracting -cellulose , however large-scale comparisons between them are rare and the most common methods are often employed without use of a method blank, hindering understanding on how the extraction methodology affects the carbon isotope composition of the -cellulose during the extraction. We present data where each step of the common Brendel method was individually targeted for isotope analysis, tracking the change in 13C of -cellulose throughout the extraction. We found that significant but consistent isotopic changes (~ 1) were caused by multiple steps of the extraction on pure -cellulose. Based on this analysis, a correction factor can be established for the Brendel method when used in synthesizing datasets from multiple sources with different extraction methods. The results suggests that other methods of extraction should undergo the same scrutiny.