浊点萃取-火焰原子吸收光谱法测定土壤中的有效态钴  

Determination of Available Cobalt in Soils by Flame Atomic Absorption Spectrometry with Cloud Point Extraction

作　　者：杨琳[1] 李雪蕾[1] 王相舒[1] 王晓燕[1] 王文涛[1] 韩华云[1] 

机构地区：[1]郑州大学化学与分子工程学院,河南郑州450052

出　　处：《岩矿测试》2013年第5期775-779,共5页Rock and Mineral Analysis

基　　金：郑州大学大学生创新训练计划基金项目(2012cxsy080)

摘　　要：重金属的毒性和迁移性不仅取决于总量,而且取决于特殊的化学形态,其中有效态容易被植物吸收,对人体的危害更严重,因此准确测定土壤中的重金属有效态含量非常重要。但土壤中有效态金属的含量通常很低,而且干扰组分多,直接进行仪器分析测定比较困难。本文以0.1 mol/L盐酸为浸提剂,甲基红为螯合剂,Triton X-114为表面活性剂,建立了一种浊点萃取-火焰原子吸收光谱测定土壤中有效态钴的新方法,提高了测定的选择性和灵敏度。在最佳实验条件下,钴的线性范围为0.10～2.00μg/mL,方法检出限为0.03μg/mL,方法回收率为94.0%～104.0%,应用于分析0.5μg/mL钴标准溶液,9次平行测定的相对标准偏差为3.3%。通过测定发现不同地区土壤中有效态钴占钴总量的比例差别很大,土壤中重金属有效态含量更能直观地传递出重金属在土壤中的迁移能力、存在状态以及危害程度等信息。Toxicological studies have shown that available heavy metals is critical for risk assessment purpose since their transformations and potential toxicity depends,not only on total content,but also on the special chemical forms of the heavy metals.It is very difficult to measure heavy metals in soil by direct instrumental analysis due to the low contents of avalaible metals in soil samples and interference components.In the present paper,a novel procedure was proposed for the determination of available cobalt in soils by flame atomic absorption spectrometry with Cloud Point Extraction（CPE）.In the proposed approach,0.1 mol / L hydrochloric acid（HCl） was used as the extraction agent and methyl red as a chelating agent,with Triton X-114 being selected as the surfactant.The method improved the selectivity and sensitivity of determination.Under optimized conditions,the linear range is from 0.10 to 2.00 μg / mL,the detection limit is 0.03 μg / mL,the recoveries of the procedure ranged from 94.0% to 104.0%,and the relative standard deviation is 3.3%（ρ = 0.5 μg / mL,n = 9）.It was found that the proportion of available cobalt is very different in soils from different areas.The contents of available heavy metals better reflected the information concerning the migration ability of heavy metals in soil,occurrence status and risk assessment.

关 键 词：土壤 有效态钴 浊点萃取 火焰原子吸收光谱法 

分 类 号：S151.93[农业科学—土壤学]