高氯酸-氢氟酸联合消解法测定土壤中全量氮磷钾

Determination the total amount of nitrogen,phosphorus and potassium in the soil by perchloric acid-hydrofluoric acid digesting system

为提高土壤样品中全氮、全磷和全钾含量的检测效率。以四种土壤标准物质为试验材料,研究H_(2)SO_(4)+HClO_(4)+HF、H_(2)SO_(4)+HClO_(4)、HClO_(4)+HF三种酸系,以及不同用酸比例的对试验结果的影响,旨在建立一种同时测定土壤中全氮、全磷和全钾的方法。结果表明:采用酸系HClO_(4)+HF(4∶2)进行消解时,获得的试验结果最佳。四种土壤标准物质的全氮、全磷和全钾含量均在其证书标准值范围内,证明方法具有较高的准确度;对标准物质重复测定11次,全氮、全磷和全钾的相对标准偏差(RSD)分别为1.04%、1.07%和1.19%,证明方法的重现性和精密度良好;加标回收率全氮在96.4%~105.0%之间,全磷在94.2%~103.4%之间,全钾在95.7%~96.18%之间,均符合试验要求。该研究在保证准确度和精确度的基础上简化试验步骤,降低试验成本,为土壤中全氮、全磷和全钾的检测提供一种快速、高效的检测分析方法。

To improve the simultaneous determination efficiency of the total amount of nitrogen(N),phosphorus(P)and potassium(K)in soils,four standard soil test substances were used as test materials,three digestion acids systems,the sulfuric acid(H_(2)SO_(4))-perchloric acid(HClO_(4))-hydrofluoric acid(HF),H_(2)SO_(4)-HClO_(4),HClO_(4)-HF,and the effects of different acid ratios were studied in the research.The results showed that HClO_(4)-HF had the best digestion effect at a ratio of 4∶2.The total N,P,and K contents of the four soil reference materials tested in the study were all within the standard value range of the certificate,which proved the high accuracy of the method.The relative standard deviations(RSD)of total N,P,and K were 1.04%,1.07%and 1.19%,respectively,suggested the good reproducibility and precision of the method.The recovery rate of total N was from 96.4%to 105.0%,the recovery rate of total P were from 94.2%to103.4%,and the recovery rate of total K were from 95.7%to 96.18%.In conclusion,this study simplifies the test procedure,reduces the test cost,and provides a fast and efficient method for the simultaneous detection of total N,P,and K in the soil.