自动滴定仪测定土壤有机碳及其组分的方法优化  

Method Optimization for the Determination of Soil Organic Carbon and Its Components by Automatic Titrator

作　　者：李朝英[1] 郑路[1,2] 郑之卓 李华 王亚南[1,2] 明安刚 LI Zhaoying;ZHENG Lu;ZHENG Zhizhuo;LI Hua;WANG Yanan;MING Angang(Experimental Center of Tropical Forestry,Chinese Academy of Forestry,Pingxiang 532600,China;Guangxi Youyiguan Forest Ecosystem National observation and Research Station,Youyiguan Forest Ecosystem Observation and Research Station of Guangxi,Pingxiang 532600,China;School of Chemistry and Molecular Engineering,East China University of Science and Technology,Shanghai 201400,China)

机构地区：[1]中国林业科学研究院热带林业实验中心,广西凭祥532600 [2]广西友谊关森林生态系统国家定位观测研究站,崇左凭祥友谊关森林生态系统广西野外科学观测研究站,广西凭祥532600 [3]上海华东理工大学化学与分子工程学院,上海201400

出　　处：《岩矿测试》2024年第4期632-640,共9页Rock and Mineral Analysis

基　　金：崇左凭祥友谊关森林生态系统广西野外科学观测研究站科研能力建设项目(桂科22-035-130-03);广西林业科技推广示范项目(桂林科研[2022]第27号,2023GXLK45)。

摘　　要：土壤有机碳及其组分(颗粒有机碳、矿物结合态有机碳等)是反映土壤质量的关键性指标,开展准确高效地测定这些指标对相关研究具有重要意义。自动滴定仪与传统人工滴定相比,人员工作强度低,检测准确,但检测效率不及人工滴定的30%。为解决此问题,本文探讨了4种氧化剂加入量对测定有机碳的影响,研究了提前预加滴定液对检测效率提高的效果。最终优选氧化剂加入量为2mL,预加滴定液量以空白样滴定量的1/3计,建立了用于测定土壤有机碳的自动滴定仪法。采用有机碳不同水平的土壤样品和标准物质对方法进行验证,并与人工滴定进行比较,结果表明,自动滴定仪法与人工滴定法无显著性差异,方法的相对标准偏差(RSD,n=6)在2.10%~12.96%,加标回收率在93.37%~98.06%,标准物质相对误差为4.31%~4.79%;优化后的自动滴定法单个试样滴定用时由11min缩短到3.5min,整体检测效率高于人工滴定,而试剂耗用量仅是人工滴定法的40%。自动滴定仪法显著提升了有机碳的检测能力。The rapid and accurate detection of soil organic carbon and its components(such as particulate organic carbon and mineral-associated organic carbon)is of great significance because they are the key indicators reflecting soil quality.Compared with manual titration,the automatic titrator has a low work intensity and accurate detection,but its detection efficiency is less than 30%of that of manual titration.To solve this problem,the influence of the addition amount of four oxidants on the determination of organic carbon was explored,and the effect of pre-adding titrant in advance on the improvement of detection efficiency was studied.Finally,the optimal addition amount of oxidant was 2mL,and the amount of the pre-added titrant was one-third of the titration amount of the blank sample.An automatic titrator method for the determination of soil organic carbon was established.This method was verified by using soil samples with different levels of organic carbon and reference substances and was compared with manual titration.The results showed that there was no significant difference between the automatic titrator and the manual titration.The relative standard deviation(RSD,n=6)of the method was 2.10%-12.96%,the recovery rate of standard addition was 93.37%-98.06%,and the relative error of the reference material was 4.31%-4.79%.The titration time of a single sample was shortened from 11min to 3.5min,and the overall detection efficiency was higher than that of manual titration.The reagent consumption was only 40% of that of manual titration.The automatic titrator significantly improved the detection ability of organic carbon.

关 键 词：自动滴定仪 人工滴定 土壤有机碳 氧化剂加入量 预加滴定量 

分 类 号：P595.2[天文地球—地球化学] S151.93[天文地球—地质学]