利用多相红外碳硫分析仪测定土壤和沉积物中总有机碳研究

Determination of the Total Organic Carbon in Soil and Sediment by Phase Infrared Carbon and Sulfur Analyzer

有机碳分析传统方法中,重铬酸钾容量法容易受还原性组分影响而导致测试结果偏高;常规高频红外燃烧法缺少专门的除酸装置,一般采用高温加热抽滤的方法除酸,除酸程序复杂,生产效率较低;比色法受温度影响大,结果稳定性差,且对分析人员能力要求高。而本文中,样品与盐酸反应去除无机碳,烘干残留酸和水分后,在高温通氧条件下发生催化氧化反应,碳燃烧生成二氧化碳,去除水分和残留酸后采用多相红外碳硫分析仪自动检测总有机碳的含量,设备具有自动除酸装置,生产效率高,使用寿命长,适合大批量样品生产,通过优化残留酸处理、测量时间、分解酸选择、加酸程序等试验条件,提升了方法稳定性、准确率,降低了方法检出限,通过标准物质验证,方法检出限为0.03%,精密度(RSD,n=12)均小于8%,采用此实验方法分析土壤和沉积物国家标样,结果满意。

Among the traditional methods of organic carbon analysis,the potassium dichromate volumetric method is easily affected by the reducing components,which leads to the higher test results.Conventional high frequency infrared combustion method lacks special acid removal device,generally using high temperature heating extraction filter method to remove acid,acid removal procedures are complex,low production efficiency;Colorimetric method is affected by temperature and has poor colorimetric stability.In this paper,samples react with hydrochloric acid to remove inorganic carbon reaction,drying after the residual acid and water,in high temperature catalytic oxidation reaction under the condition of oxygen,carbon combustion generates carbon dioxide,removing moisture and acid residue after using polyphase infrared carbon sulfur analyzer automatically detect the content of total organic carbon,equipment with automatic acid removal equipment,high production efficiency,long service life,it is suitable for mass sample production.The stability and accuracy of the method are improved and the detection limit of the method is reduced by optimizing the test conditions such as residual acid treatment,measurement time,decomposition acid selection and acid addition procedure.The detection limit of the method is 0.03%and the precision(RSD,n=12)of the method is less than 8%.National standard samples of soil and sediment were analyzed by this method with satisfactory results.