EDTA-乙酸铵浸提ICP-OES法直接测定土壤中的交换性钾钠钙镁锰

目的]土壤交换性能可以用来评价土壤的保肥供肥能力,研究土壤中交换性阳离子为改良土壤和合理施肥提供重要依据。方法]采用0.005mol/LEDTA-乙酸铵混合溶液作为交换提取剂,与土壤中的Ca2＋、Mg2＋、Mn2＋、Na＋、K＋等阳离子进行交换,浸取液干过滤后使用电感耦合等离子体光谱仪（ICP-OES）直接测定土壤中多种交换性阳离子。结果]该方法的钙（Ca）、镁（Mg）、钾（K）、钠（Na）和锰（Mn）检出限分别为：0.1500、0.0075、0.2500、0.0640、0.0010μg/ml。该方法快速、简便。标准物质ASA-1a,ASA-4a,ASA-5a,ASA-6a,ASA-7测定钙、镁、钾、钠和锰的相对误差（RE）分别为0.62%～7.50%,2.22%～9.52%,1.59%～4.88%,2.98%～10.00%和3.23%～9.38%。5次测定ASA-1a测定结果的RSD分别为：1.69%、1.58%、1.33%、5.80%、4.20%,ASA-6a测定结果的RSD分别为：3.20%、2.21%、2.89%、2.25%、7.87%。结论]分析结果符合《DD2005-03生态地球化学评价样品分析技术要求》,为土壤阳离子交换性阳离子的简便快速测定提供新的试验方法。

Direct Determination of the Exchangeable K, Na, Ca, Mg and Mn in Soil with the Method of EDTA-Ammonium Acetate Extracting ICP-OES

Objective]The important basis of the soil improvement and rational fertilization was provided through the research on exchangea-ble cation in soil because the amount of the cation could be used to evaluate the fertilizer supply and preservation capacity of soil.Method] The mixed solution of the EDTA-ammonium acetate of 0.005 mol/L as exchange extractant was acted with Ca2+ ,Mg2+,Mn2+ ,Na+ ,K+ and other cations in soil and the exchangeable cation in the solution was measured with the inductively coupled plasma spectrometer(ICP-OES) after it was filtered.Results]The detection limitation of the method in the content of calcium(Ca) ,magnesium(Mg) ,potassium(K) ,sodium (Na) and manganese(Mn) was:0.150 0,0.007 5,0.250 0,0.064 0 and 0.001 0 μg/ml,respectively.The method was quick and convenient.The relative error(RE) of the Standard Material:ASA-1a,ASA-4a,ASA-5a,ASA-6a and ASA-7 in the determination of calcium, magnesium,potassium,sodium and manganese was 0.62%-7.50% ,2.22%-9.52% ,1.59%-4.88% ,2.98%-10.00% and 3.23%-9.38% .The RSD of 5 times'determination results of ASA-1a was 1.69% ,1.58% ,1.33% ,5.80% and 4.20% ; ASA-6a,3.20% , 2.21% ,2.89% ,2.25% and 7.87% ,respectively.Conclusion]It was found the determination results were matched with "The Technical Requirement of the Eco-geochemical Assessment of Sample of DD2005-03" and a new test method to simple and rapid determine the exchange cations in soil was provided.