三氯化六氨合钴浸提法测定土壤阳离子交换量的方法验证

Hexammine Cobaltic Chloride Exchange Method Verification for Soil Cation-Exchange Capacity

通过测定检出限、测定下限、准确度和精密度等特征参数对《土壤阳离子交换量的测定三氯化六氨合钴浸提-分光光度法》(HJ 889-2017)进行了实验室方法验证,并采用该方法应用于实际土样的测定。结果显示,三氯化六氨合钴在浓度为0~1.49 cmol/L范围内与吸光度值呈现出较好的线性关系,其相关系数R=0.9999。实验室测得土壤阳离子交换量检出限为0.6 cmol^(+)/kg,小于方法要求的0.8 cmol^(+)/kg,测定下限为2.4 cmol^(+)/kg,小于方法标准3.2 cmol^(+)/kg,对土壤阳离子交换量为9.30±0.39 cmol^(+)/kg的有证标准样品(编号为HTSB-4)以及5.6±0.8 cmol^(+)/kg的有证标准样品(编号HTSB-6)进行六次测定,测得均值分别为9.4 cmol^(+)/kg和5.3 cmol^(+)/kg,相对偏差分别为2.8%及6.8%,符合实验室技术指标要求。实验室对实际土壤平行测定6次,相对偏差为2.1%。方法易操作,精密度好。

The report was based on the standard for the hexammine cobaltic chloride exchange method of cation exchange capacity(CEC)in soil(HJ 889-2017),measured the detection limit,the lower limit of measurement and other parameters to verify the potassium dichromate method and the real soil sample results was also discussed.The results showed that there was a good linear relationship between the absorbance value and the concentration of[Co(NH3)6]3+in the range of 0 to1.49 cmol/L,and the phase relationship was 0.9999.The results showed that the detection limit of CEC in the laboratory was 0.6 cmol^(+)/kg,less than the 0.8 cmol^(+)/kg required by the method and the lower limit of determination in the laboratory was 2.4 cmol^(+)/kg,less than the 3.2 cmol^(+)/kg required by the method.Six laboratory tests were carried out on the certified standard samples with concentrations of 9.30±0.39 cmol^(+)/kg and 5.6±0.8 cmol^(+)/kg.The results showed that the average values were 9.4 cmol^(+)/kg and 5.3 cmol^(+)/kg,the relative deviations were 2.8%and 6.8%,respectively.The accurate and precision can satisfy the needs of analysis.Six parallel laboratory measurements of actual soil showed the method was easy to operate and precise.the relative deviation was 2.1%.