Distribution and isotopic composition of n-alkanes from grass, reed and tree leaves along a latitudinal gradient in China

Abstract

Living terrestrial higher plants including grass, reedand tree leaves were collected in spring and autumn of2001–2005 from salt marshes at Huatugou, Qaidam ba-sin; the Ruoergai grassland, Sichuan; the banks of theXihu Lake (West Lake), Hangzhou; the bank of theDianchi Lake, Yunnan; and Nanning in Guangxi (Fig. 1and Table 1).Immediately after collection, non-indigenous materialin leaves was removed and the leaves were washed re-peatedly with tap water and then rinsed with distilledwater. All samples were dried at room temperature andcrushed to fine powder. Powders were kept frozen untilanalysis. Powdered samples were extracted in a Soxhletapparatus with a mixture of dichloromethane-methanol(2:1, v/v). The extracts were filtered and evaporated, andthen fractionated with a column chromatography onalumina over silica gel (Duan