Abstract: Isotopes of peat α-cellulose have been increasingly applied in paleoclimatic and paleoenvironmental reconstructions, therefore, the simplification and unification of the extraction procedure for peat α-cellulose is urgently needed. Until now, the discrepancy in peat α-cellulose extraction procedures largely limited the comparative studies of reported isotopic data of peat α-cellulose from different labs and research groups. Based on the classical peat α-cellulose extraction procedure, and referring to the relevant α-cellulose extraction procedures for tree rings, lacustrine sediments and so on, after a systematically and repeatedly conditional experiment, the paper finally established an effective peat α-cellulose extraction procedure. The improved peat α-cellulose extraction procedure are simply outlined as following:(1)original peat core samples were washed with deionized water in a specific and simple cleaning device, for the effective removal of clay and minerals;(2)the wet samples were dried in the oven(~70℃), and then were finely powdered in an agate mortar with pestle;(3)humus in samples were removed by NaOH(5%)dissolution at room temperature for 24 h;(4)carbonate in samples were removed by HCl(5%)dissolution in a 80℃ water bath for 1 h;(5)lignin in samples were removed by sodium chlorite and acetic acid(acetic acid were firstly added)dissolution in a 80℃ water bath for 1 h;(6)remains of non-cellulose poly-saccharides(hemicellulose)were removed by NaOH(10%)dissolution in a 80℃ water bath for 1 h, and then by NaOH(17%)dissolution at room temperature for 45 min;(7)the samples were neutralized with HCl(1%), and then washed with a large amount of deionized water;(8)the extracts were homogenized by supersonically treated for 10 min;(9)the extracted α-cellulose samples were dried in a~70℃ oven. The purity degree was examined by comparative infrared spectrum analysis of α-cellulose extracted from peat and modern plant leaf with international standard tree ring α-cellulose. Finally, carbon isotopic composition of α-cellulose extracted from 40 peat-core samples were double or triple measured. The analyses on the obtained carbon isotopic data demonstrated that the established peat α-cellulose extraction procedure is effective and efficient. The improvements of the peat α-cellulose extraction procedure are mainly focus on the following 4 aspects:(1)a simple cleaning device was designed for the effective removal of impurities, such as clay and minerals;(2)the whole extraction procedure was performed in the same 10 ml Teflon centrifuge tube to avoid the loss of samples, and a centrifuge machine was used for the reduction of the extraction time;(3)the organic solvent extraction was replaced by bleaching by sodium chlorite solution and alkaline cleaning by sodium hydroxide solution with different concentrations;(4)final homogenization of the extracted α-cellulose for better representativeness. Briefly, a better peat α-cellulose extraction procedure has been established, due to its minor sample loess, easy and quick handling, stable and precise isotopic data.

Key words: peat samples, α-cellulose extraction, stable isotopes