The Determination of Available Molybdenum in Soil by Rapid Catalytic Polarography
Available molybdenum in soil is an important proxy of ecological geochemistry evaluation. The classic method to determine available molybdenum in soil is catalytic polarography, which uses oxalic acid-ammonium oxalate (Tamm solution) as an extracting agent. The procedure to eliminate the iron ion, m...
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Science Press, PR China
2014-07-01
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| Series: | Yankuang ceshi |
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| Online Access: | http://www.ykcs.ac.cn/en/article/id/6ce7fc6c-7561-43e9-9c46-5c04a73f2949 |
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| author | CHEN Zhi-hui SUN Luo-xin ZHONG Li-xiang WANG Yan SHANG Bao-zhong XIAO Shu |
| author_facet | CHEN Zhi-hui SUN Luo-xin ZHONG Li-xiang WANG Yan SHANG Bao-zhong XIAO Shu |
| author_sort | CHEN Zhi-hui |
| collection | DOAJ |
| description | Available molybdenum in soil is an important proxy of ecological geochemistry evaluation. The classic method to determine available molybdenum in soil is catalytic polarography, which uses oxalic acid-ammonium oxalate (Tamm solution) as an extracting agent. The procedure to eliminate the iron ion, manganese ion, and oxalate and organics interferences is complicated and time consuming. Consequently, the interference mechanism is discussed in this paper. Since oxalate and organics are reductive, the metallic ions with variable valences changed to a reduction state during leaching. The oxidation-reduction reaction proceeds between the before mentioned materials and sodium chlorate in the measurement system, affecting the sensitivity of the catalytic wave. The method presented in this article is to add solid natrium hydroxide into oxalic acid-ammonium oxalate solution so that iron and manganese impurities can be removed through precipitation separation. Afterwards, HNO3-H2SO4 was used to destroy the organics and oxalate in the leaching liquor. In the system of molybdenum-benzoglycolic acid-chlorate-sulfuric acid, available Mo in soil standard reference materials was determined by polarographic catalytic wave. Compared with the classic interference elimination method, this method effectively reduces reagent types, operating time and error sources in analysis. The detection limit of this method is 0.0015 μg/g, which is below the detection limit of the classic method (0.0068 μg/g). The precision (RSD, n=12) is less than 7% and relative error is less than 8%. Measured values of soil standard reference materials are in agreement with the certified values. Verified by thousands of soil samples, this method is suitable to measure available Mo in soil that pH range is from 3.6 to 10.5. The measuring range of available Mo is 0.005-2 mg/kg. The method has the advantage of simple operation, short process, is accurate and has stable analysis results. It could be widely used in large quantities for rapid analysis of available Mo in soil. |
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| language | English |
| last_indexed | 2024-04-10T16:10:18Z |
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| spelling | doaj.art-4ca64b02ce5d4c70a721e4637a43816c2023-02-10T01:00:32ZengScience Press, PR ChinaYankuang ceshi0254-53572014-07-01334584588ykcs-33-4-584The Determination of Available Molybdenum in Soil by Rapid Catalytic PolarographyCHEN Zhi-hui0SUN Luo-xin1ZHONG Li-xiang2WANG Yan3SHANG Bao-zhong4XIAO Shu5Henan Institute of Geological Survey, Zhengzhou 450001, ChinaHenan Institute of Geological Survey, Zhengzhou 450001, ChinaHenan Province Rock & Mineral Testing Centre, Zhengzhou 450012, ChinaHenan Institute of Geological Survey, Zhengzhou 450001, ChinaHenan Institute of Geological Survey, Zhengzhou 450001, ChinaHenan Institute of Geological Survey, Zhengzhou 450001, ChinaAvailable molybdenum in soil is an important proxy of ecological geochemistry evaluation. The classic method to determine available molybdenum in soil is catalytic polarography, which uses oxalic acid-ammonium oxalate (Tamm solution) as an extracting agent. The procedure to eliminate the iron ion, manganese ion, and oxalate and organics interferences is complicated and time consuming. Consequently, the interference mechanism is discussed in this paper. Since oxalate and organics are reductive, the metallic ions with variable valences changed to a reduction state during leaching. The oxidation-reduction reaction proceeds between the before mentioned materials and sodium chlorate in the measurement system, affecting the sensitivity of the catalytic wave. The method presented in this article is to add solid natrium hydroxide into oxalic acid-ammonium oxalate solution so that iron and manganese impurities can be removed through precipitation separation. Afterwards, HNO3-H2SO4 was used to destroy the organics and oxalate in the leaching liquor. In the system of molybdenum-benzoglycolic acid-chlorate-sulfuric acid, available Mo in soil standard reference materials was determined by polarographic catalytic wave. Compared with the classic interference elimination method, this method effectively reduces reagent types, operating time and error sources in analysis. The detection limit of this method is 0.0015 μg/g, which is below the detection limit of the classic method (0.0068 μg/g). The precision (RSD, n=12) is less than 7% and relative error is less than 8%. Measured values of soil standard reference materials are in agreement with the certified values. Verified by thousands of soil samples, this method is suitable to measure available Mo in soil that pH range is from 3.6 to 10.5. The measuring range of available Mo is 0.005-2 mg/kg. The method has the advantage of simple operation, short process, is accurate and has stable analysis results. It could be widely used in large quantities for rapid analysis of available Mo in soil.http://www.ykcs.ac.cn/en/article/id/6ce7fc6c-7561-43e9-9c46-5c04a73f2949soilavailable molybdenumcatalytic polarographynatrium hydroxide |
| spellingShingle | CHEN Zhi-hui SUN Luo-xin ZHONG Li-xiang WANG Yan SHANG Bao-zhong XIAO Shu The Determination of Available Molybdenum in Soil by Rapid Catalytic Polarography Yankuang ceshi soil available molybdenum catalytic polarography natrium hydroxide |
| title | The Determination of Available Molybdenum in Soil by Rapid Catalytic Polarography |
| title_full | The Determination of Available Molybdenum in Soil by Rapid Catalytic Polarography |
| title_fullStr | The Determination of Available Molybdenum in Soil by Rapid Catalytic Polarography |
| title_full_unstemmed | The Determination of Available Molybdenum in Soil by Rapid Catalytic Polarography |
| title_short | The Determination of Available Molybdenum in Soil by Rapid Catalytic Polarography |
| title_sort | determination of available molybdenum in soil by rapid catalytic polarography |
| topic | soil available molybdenum catalytic polarography natrium hydroxide |
| url | http://www.ykcs.ac.cn/en/article/id/6ce7fc6c-7561-43e9-9c46-5c04a73f2949 |
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