分光光度法测定土壤中阳离子交换量的优化改进

Optimization and Improvement of Sectrophotometry Method to Determine Cation Exchange Capacity in Soil

为了提高土壤中阳离子交换量检测的准确度和效率,针对国标方法的不足,在原理不变的条件下对空白、浸提、离心等实验步骤进行优化。通过对比实验、平行性实验以及条件实验,分析本方法的准确度、精密性和稳定性。结果表明:通过实验测试,对空白试验进行重新定义,将国标方法中的浸提时间由60 min优化为30 min,离心时间由10 min优化为20 min,大大缩减了一个样品的测试时间。在该条件参数下,对4种不同类型的国家土壤有证标准物质进行测试,得出阳离子交换量测定值与土壤标准物质标准值吻合。本方法效率高,准确度和精密性良好,操作简单,适用于大批量土壤中阳离子交换量的测定。

To improve the detection accuracy and efficiency of the cation exchange capacity in soil,and in view of the shortcomings of the national standard method,the authors optimized the experimental steps such as blank test,extraction and centrifugation under the same principle.The accuracy,precision and stability of the new method were analyzed through comparative experiments,parallel experiments and condition experiments.The results showed that the blank test was redefined by experiments,and the extraction time in the national standard method was optimized from 60 min to 30 min,as well as the centrifugation time was optimized from 10 min to 20 min,which greatly shortening the test time of a sample.Under these conditions,four different types of the certified reference materials of national soil were tested,and it was found that the measured values of cation exchange capacity were in agreement with the standard values of the certified reference materials of soil.This method possesses the advantages of high efficiency,excellent accuracy,precision,and simple operation,and is suitable for the determination of cation exchange capacity in large quantities of soil samples.