A rapid and simple method to isolate pure alpha-cellulose

A protocol is described to isolate small quantities of highly purified cellulose for isotopic analysis of 10-100 mg samples of secondary (Pinus sylvestris L.) and primary (Rubus idaeus L.) plant cell wall material. Elemental analysis of 350 cellulose samples isolated from pine wood samples estimated the relative carbon content to be ca. 43.7% ± 1.2%. This value indicates that the cellulose quality is high and that the protocol is highly reproducible. High-performance anion exchange chromatography with pulsed amperometric detection of hydrolysis products quantified the purity of the cellulose as ca. 99% for wood cellulose and primary cell wall cellulose. DRIFT spectroscopy corroborated this purity and found no evidence of cellulose degradation. Carbon isotopic composition of the purified cellulose using mass spectrometry was measured with an accuracy of 0.11% (standard deviation). The method is rapid (56 samples may be routinely processed within 8 h) and requires only standard laboratory equipment and chemicals.