高频红外碳硫仪测定地球化学样品中有机碳

Determination of organic carbon in geochemical samples by high frequency infrared carbon-sulfur meter

利用高频红外碳硫仪,建立盐酸预处理-红外吸收法测定地球化学样品中有机碳含量的分析方法。对样品的称取量、助熔剂的添加量、盐酸溶液的体积分数等条件进行了优化。高频红外碳硫分析仪专用陶瓷坩埚经过1200℃高温处理后,能够有效降低空白值。优化后的分析条件为:确定称样量为50 mg,使用体积分数为40%的盐酸溶液,选择0.5 g纯铁屑和1.5 g钨粒作为助熔剂;对土壤和水系沉积物等不同类型的地球化学样品进行6次测定,选择国家一级标准物质作为实验对象,其检测结果的相对误差为0.23%~3.63%,相对标准偏差为0.592%~4.551%,符合《多目标区域地球化学调查规范》规定,满足分析测试要求。该方法测定结果准确、稳定,流程短、操作简单,适用于地球化学样品中有机碳含量的测定。

An analytical method for the determination of organic carbon content in geochemical samples by hydrochloric acid pretreatment-infrared absorption was established by using high frequency infrared carbon and sulfur analyzer.The weighing amount of the sample,the addition amount of flux and the volume fraction of hydrochloric acid solution were optimized.The special ceramic crucible for high frequency infrared carbon and sulfur analyzer could effectively reduce the blank value after high temperature treatment at 1200℃.The optimized analysis conditions were as follows:50 mg sample was determined,40%hydrochloric acid solution was used,and 0.5 g pure iron filings and 1.5 g tungsten particles were selected as flux;different types of geochemical samples,such as soil and river sediments,were determined for six times,and the national first-class standard materials were selected as the experimental objects.The relative error of the detection results was 0.23%to 3.63%,and the relative standard deviation was 0.592%to 4.551%,which met the requirements of the multi-objective regional geochemical survey.This method is accurate,stable,short and easy to operate,and is suitable for the determination of organic carbon in geochemical samples.