植物和土壤δ^(13)C的分析误差校正与数据标准化  

Analytical error correction and data normalization in the determination of δ^(13)C in plant and soil

作　　者：王静[1] 范昌福[2] 张琳[3] 曲冬梅[4] 田有荣 温学发[1,6,7] WANG Jing;FAN Chang-fu;ZHANG Lin;QU Dong-mei;TIAN You-rong;WEN Xue-fa(Key Laboratory of Ecosystem Network Observation and Modeling,Institute of Geographic Sciences and Natural Resources Research,Chinese Academy of Sciences,Beijing 100101,China;Institute of Mineral Resources,Chinese Academy of Geological Sciences,Beijing 100037,China;Institute of Hydrogeology and Environmental Geology,Chinese Academy of Geosciences,Shijiazhuang 050061,China;Institute of Tibetan Plateau Research,Chinese Academy of Sciences,Beijing 100101,China;Thermo Fisher Scientific,Shanghai 201206,China;College of Resources and Environment,University of Chinese Academy of Sciences,Beijing 100190,China;Beijing Yanshan Earth Critical Zone National Research Station,University of Chinese Academy of Sciences,Beijing 101408,China)

机构地区：[1]中国科学院地理科学与资源研究所,生态系统网络观测与模拟重点实验室,北京100101 [2]中国地质科学院矿产资源研究所,北京100037 [3]中国地质科学院水文地质环境地质研究所,石家庄050061 [4]中国科学院青藏高原研究所,北京100101 [5]赛默飞世尔科技(中国)有限公司,上海201206 [6]中国科学院大学资源与环境学院,北京100190 [7]北京燕山地球关键带国家野外科学观测研究站,中国科学院大学,北京101408

出　　处：《生态学杂志》2023年第1期228-236,共9页Chinese Journal of Ecology

基　　金：国家自然科学基金项目(41830860和32001137)资助。

摘　　要：植物和土壤中稳定碳同位素(δ^(13)C)可用于指示、示踪和整合碳循环关键过程与功能。双路和连续流气体稳定同位素比值质谱仪(IRMS)是δ^(13)C的两种测试技术,其精度和准确度受分析误差和数据标准化方法影响。分析误差包括记忆效应、时间漂移和信号强度依赖性等。将测定序列按样品δ^(13)C从低到高排列或延长气路冲洗时间消除或降低记忆效应;在测样序列中内插标准物质并建立测定时间与分析误差的函数关系校正时间漂移;信号强度依赖性应先校正样品空白效应,再校正仪器非线性响应。数据标准化包括标准物质和数据标准化方法选择。选择的标准物质δ^(13)C应涵盖待测样品δ^(13)C,且遵循同等处理原则;标准物质数量≥4或每个标准物质重复测定次数≥4;数据标准化体系应长期稳定,并添加监测标准物质。Stable isotopic composition of carbon(δ^(13)C) in plants and soil can indicate, trace, and integrate key processes and functions of carbon cycling. Dual-inlet and continuous-flow isotope ratio mass spectrometry(IRMS) are two techniques for determining δ^(13)C of carbon-containing compounds. The precision and accuracy of analyzed data depends on analytical error and data normalization method. Analytical errors include memory effect, time drift and signal intensity-dependence effect, etc. The easiest method to eliminate or minimize the memory effect is to set up a measurement sequence ranging from low to high isotopic composition of the actual samples, or increasing the flushing time of the tube. A sufficient number of identical standards should be included with the measurement sequence, and the function of measurement time and analysis error of identical standards are used to correct time drift. Signal intensity dependence can be corrected by considering the impacts of blank effect and nonlinear response of instrument separately, with the blank effect considered first, and the nonlinear response of the instrument second. Data normalization strategy includes the selection of standards and normalization methods. The δ^(13)C of selected standards should bracket the range of δ^(13)C of samples. Based on the principle of identical treatment, the selected standards should share similar physical and chemical properties with the samples, and undergo the same analytical procedure. The number of selected standards should be ≥4, or the number of repeated determinations for each standard should be ≥4. The same set of standard materials should always be used for a particular element and be specific to an analytical technique. The measurement sequence should add quality control standard material to monitor the long-term accuracy of the analytical results.

关 键 词：记忆效应 时间漂移 信号强度依赖性 数据标准化 碳稳定同位素 

分 类 号：Q948.113[生物学—植物学]