| 摘要: |
| 针对现行土壤污染物环境标准和分析方法都是用总砷表示，而对水溶性砷研究较少的现状，选择蠕动注射方法添加还原剂KBH4-NaOH溶液，通过控制样品溶液pH，对As(Ⅲ)和As(Ⅴ)进行了分步还原，用硝酸银-聚乙烯醇-乙醇溶液作吸收液来吸收还原生成的AsH3，分光光度法在400 nm波长下测定吸收液的吸光度，求算As(Ⅲ)和As(Ⅴ)含量。用这种方法对模拟环境砷污染水样和厌氧水稻土中As(Ⅲ)和As(Ⅴ)的测定进行了研究。结果表明，砷质量浓度为0～0.5 mg/L时，吸光度和砷质量浓度符合朗伯－比尔定律，标准溶液测定的相对误差为-3.60%～2.20%，检测限为0.6 μg；环境水样测定的As回收率为97.14%～103.4%，与Ag－DDC标准方法比较无显著差异；水稻土中总砷和As(Ⅲ)的回收率分别为98.36%～102.8%及56.02%～65.34%；对22种无机离子的干扰试验测定表明，在容许量内无干扰。 |
| 关键词: 厌氧水稻土 分光光度法 砷污染 As(Ⅲ) As(Ⅴ) |
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| 基金项目:国家自然科学基金资助项目(40271067)；教育部博士学科点专项科研基金项目(20020712009) |
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| A determination method of the soluble trace As(Ⅲ) and As(Ⅴ) in the anoxic paddy soils |
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| Abstract: |
| The current environmental standards of soil pollutants and analysis methods all use the total As but there are not so many taking the soluble trace Arsenic as the environmental index.In this article,the samples were treated with added sodium borohydride (KBH4) as the reduction by Peristaltic pump injection,Arsenic(Ⅲ) and Arsenic(Ⅴ) could be detected by adjusted pH of the sample solution,and the produced arsine (AsH3) absorbed by the solution of AgNO3-PVA-C2H5OH (1∶1∶2) was determined directly by colorimetric analysis in the wavelength of 400 nm.The results showed that the detection range was 0-0.5 mg/L,relative error of the standard solution determination among -3.60%-2.20%,and the detect limit 0.6 μg.The recovery of the simulate environmental polluted water samples was ranged in 97.14%-103.4%.There was no significant difference compared with Ag-DDC standard method.The recovery of total As and As(Ⅲ)in the paddy soil samples were from 98.36% to 102.8% and from 56.02% to 65.34% in the simulate environmental polluted water samples respectively.The tolerance experiment of 22 foreign inorganic ions showed that there was no disturbance in the determination tolerance. |
| Key words: anoxic paddy soil colorimetric analysis Arsenic pollution As(Ⅲ) As(Ⅴ) |
