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    混合溶液提取-电感耦合等离子体原子发射光谱法同时测定碱性土壤中速效钾和有效磷、铁、锰、铜、锌的含量

    Extraction of Analytes with a Composite Solution-Simultaneous ICP-AES Determination of Quick-Acting K and Effective P, Fe, Mn, Cu, Zn in Alkaline Soil

    • 摘要: 称取碱性土壤样品5.000 0 g (样品预先经风干,并通过筛孔为2 mm的样筛),用碳酸氢铵、二乙烯三胺五乙酸(DTPA)和氯化钙组成的混合溶液(此溶液每升中含上述3种化合物质量依次为79.0,1.967,1.47 g,并将溶液的酸度调整在pH 7.65±0.05之间)50 mL,于25℃振荡提取90 min。将混合物用无磷滤纸干过滤,滤液用水稀释5倍后作为待测液。在电感耦合等离子体原子发射光谱分析中采用二维阵列检测器和耐氢氟酸雾化器。所测定的6种元素分别在一定的质量浓度范围内与其响应值之间呈线性关系。各元素的检出限(3s)在0.033~0.096 mg·kg-1之间。取标准物质(GBW 07459)按所提出方法进行11次平行测定,测定值与认定值相符,各元素测定值的相对标准偏差(n=11)均小于4.0%。方法分析一件试样(测定6种元素)只需2.5 h。

       

      Abstract: 5.000 0 g of alkaline soil sample (which had been dried in air and filtered through a sieve with bore size of 2 mm priliminarily) was extracted under vibration with 50 mL of a composite solution of ammonium hydrogen carbonate, diethylene triamine penta acetic acid (DTPA) and calcium chloride (amounts of the 3 compounds in 1 liter of the solution were 79.0, 1.967, 1.47 g respectively, and the acidity of the composite was adjusted to pH 7.65±0.05) at 25℃ for 90 min. The mixture was filtered on a dry phosphorus-free filter paper and the filtrate was diluted 5 times with water. The diluted solution was used for ICP-AES analysis, during which CID detector and HF-resistant atomizer were adopted. Linear relationships between values of the response signals and mass concentrations in definite ranges were obtained for the 6 elements determined. Values of detection limits (3s) for the 6 elements were found in the range of 0.033 to 0.096 mg·kg-1. A CRM of GBW 07459 was analyzed by the proposed method, results of the 6 elements obtained were in consistency with their certified values, and values of RSDs (n=11) found were all less than 4.0%. In addition, only 2.5 h were necessary for determination of the 6 elements in a single sample.

       

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