蒸汽浴-流动分析仪法测定土壤有机碳含量的方法

Determination of soil organic carbon content by steam bath-flow analyzer method

为了准确高效批量测定土壤有机碳含量,采用比色管代替消煮管,蒸汽加热消煮土壤,利用流动分析仪法测定有机碳。并将此方法与重铬酸钾氧化-外加热法(常规通用)进行了比较,探讨方法的可行性。结果表明,蒸汽浴-流动分析仪法测定土壤有机碳含量重复性试验的相对标准偏差为3.19%~9.41%,回收率为92.21%~97.63%。方法精密度及准确性良好。所测结果与重铬酸钾氧化-外加热法无显著性差异(P>0.05),两种方法拟合的回归方程:y(蒸汽浴-流动分析仪法)=0.947x(重铬酸钾氧化-外加热法)+1.621(r^(2)=0.933),两者呈良好的相关性。用两种方法测定200个土壤有机碳,蒸汽浴-流动分析仪法的检测用时是重铬酸钾氧化-外加热法用时的68%,人工操作用时是重铬酸钾氧化-外加热法用时的44%,蒸汽浴-流动分析仪法无需使用硫酸亚铁,重铬酸钾、硫酸和水用量为重铬酸钾氧化-外加热法的40%。蒸汽浴-流动分析仪法省工省时,人员工作强度低,试剂用量少,环境危害降低,检测准确高效,经济安全,可推荐为大批量土壤有机碳含量测定的方法。

In order to determine the content of organic carbon in batch of soils accurately and efficiently,the colorimetric tube was selected instead of the boiling tube,the soil was digested by steam heating,and the organic carbon content was determined by flow analyzer method,and this method was compared with the potassium dichromate oxidation external heating method(conventional and universal)to explore the feasibility of the method.The results showed that the relative standard deviation of the repeated experiments for the determination of soil organic carbon by steam bath-flow analyzer was 3.19%-9.41%,and the recovery was 92.21%-97.63%.The precision and accuracy of the method were good.There was no significant difference between the measured results and those determined by potassium dichromate oxidation-external heating method(P>0.05),the regression equation of the two methods was y(steam bath-flow analyzer method)=0.947x(potassium dichromate oxidation-external heating method)+1.621(r^(2)=0.933),the correlation between them was good.Two methods were used to determine 200 soil organic carbon.The detection time of steam bath-flow analyzer method was 68%that of potassium dichromate oxidation-external heating method,and the manual operation time was 44%that of potassium dichromate oxidation-external heating method.The steam bath-flow analyzer method did not need ferrous sulfate,the dosage of potassium dichromate,sulphuric acid and water used was 40%of that of the potassium dichromate oxidation-external heating method.The steam bath-flow analyzer method had the advantage of less testing time,less manual operation time,lower working intensity of personnel,less reagent dosage,reduced environmental hazards,more accurate and efficient in detection,more quicker and economical in operation,the method could be recommended for the determination of soil organic carbon in large quantities.