溶解性有机质对溶液中铁离子检测的影响及原因分析  

Influence of Dissolved Organic Matter on Determination of Iron in Solution and its Mechanism

作　　者：吴东明[1,2] 李怡 陈耀华[1,2] 邓晓 武春媛[1,2] WU Dongming;LI Yi;CHEN Yaohua;DENG Xiao;WU Chunyuan(Institute of Environment and Plant Protection,Chinese Academy of Tropical Agricultural Sciences,Haikou,Hainan 571101,China;Danzhou Scientific Observing and Experimental Station of Agro-Environment,Ministry of Agriculture & Rural Affairs,Danzhou,Hainan 571737,China)

机构地区：[1]中国热带农业科学院环境与植物保护研究所,海南海口571101 [2]农业部儋州农业环境科学观测实验站,海南儋州571737

出　　处：《热带作物学报》2019年第7期1441-1448,共8页Chinese Journal of Tropical Crops

基　　金：国家自然科学基金资助项目(No.41701307);中国热带农业科学院环境与植物保护研究所自主选题项目(No.hzsjy2018004)

摘　　要：铁离子的定量检测是探索铁元素地球化学过程的重要手段。环境介质中广泛存在的溶解性有机质(DOM)与铁离子存在络合作用,这可能影响溶液中铁离子的测定。为此,本文研究了DOM对原子吸收光谱法和邻菲罗啉比色法测定溶液中铁离子的影响,并初步探讨其原因。结果表明:(1)原子吸收光谱法测定铁离子的精密度与比色法相当,小于5%,但准确度更高,回收率达86.4%~97.8%;检出限更低,可达0.012 mg/L。(2)DOM对比色法的影响显著,使显色时长增加11.5 h,相对标准偏差增加1.2%~22.2%,准确度下降28.3%~44.4%。随着DOM浓度的增加,比色法的准确度下降趋势符合指数函数模型,精密度下降趋势符合先增大后减小的一元二次函数模型。而且,铁离子浓度越低,受DOM影响越大。相反,DOM对原子吸收光谱法测定铁离子的影响不大。(3)红外光谱和荧光光谱结果表明:DOM对比色法的影响主要是通过氢键结合或π-π共轭作用与铁离子/邻菲罗啉发生络合作用,减少了铁离子与邻菲罗啉的络合而产生的。Quantitative detection is a crucial technique for investigating the geochemical processes of ferric ion(Fe).However, due to the ubiquity of dissolved organic matter(DOM) in environmental medium, the combination of Fe with DOM may affect the determination of Fe in solution. Therefore, the effect of DOM between atomic absorption spectrometry(AAS) and colorimetry for Fe determination was tested. Precision of AAS was as good as colorimetry,both of them were less than 5%. However, AAS was more accurate with a recovery rate of 86.4%-97.8% and its detection limit was as low as 0.012 mg/L. DOM had a significant effect on colorimetry. The presence of DOM increased testing time and relative standard deviation of 11.5 h, 1.2%-22.2%, respectively. Moreover, the accuracy was also decreased by 28.3%-44.4%. As the concentration of DOM increasing, the accuracy was decreased in the tendency of exponential function, and the trend of the veracity fitted well with unary quadratic model. Moreover, the effect of DOM was greater with the decreasing concentration of iron. On the contrary, the presence of DOM had no significant influence on AAS. The results of EEMs and FTIR indicated that existed hydrogen bonding or π-π interaction occurred between DOM and Fe/phen that affected the interaction of Fe and colorimetry in a drive to influence the testing results.

关 键 词：铁离子 检测 溶解性有机质 准确度 精密度 

分 类 号：S31[农业科学—作物栽培与耕作技术]