自动电位滴定法测定土壤有机质含量

摘要

采用丘林滴定法与自动电位滴定法测定土壤中有机质含量,并对自动电位滴定法做了精密度和加标回收率试验.同时进行了用自动电位滴定法与手工滴定法标定硫酸亚铁标准溶液试验.结果表明,两种方法标定硫酸亚铁标准溶液结果一致,并无显著差别;丘林滴定法和自动电位滴定法均能满足土壤中有机质含量的分析要求,测定结果无显著性差异.自动电位滴定法显示了很好的准确度和重现性,加标回收率在98.43%～101.8%之间,相对标准偏差(RSD)为0.693%～0.936%,可见自动电位滴定法是一种测定土壤有机质含量的好方法.%Soil organic matter (SOM) was determined by Tyurin method with manual titration and automatically potentiometric titration. The precision and recovery rate of automatically potentiometric titration was studied. The concentration of FeSO4 standard solution of was calibrated by both automatically potentiometric titration and manual titration method. The results indicated that there was identical and no remarkable difference for calibration of FeSO4 standard solution by two methods. There was no significance difference for determining SOM by Tyurin method with manual titration and automatically potentiometric titration method which showed two methods could meet analysis requirement. Automatically potentiometric titration method revealed a good accuracy and reproducibility with recovery rate of 98. 43％ ～ 101.8％ and RSD of 0. 693％ ～ 0. 936％. It was obvious automatically potentiometric titration method could be recommended as a good method to determine SOM.