高频红外碳硫仪测定土壤/沉积物中总有机碳研究

Determination of total organic carbon in soil and sediment by high frequency infrared carbon sulfur analyzer

用盐酸预处理样品以驱除样品中的无机碳,滤出酸不溶物并洗净,待干燥后置于高频红外碳硫仪中,在富氧气流中充分燃烧,有机碳被氧化成CO2,在4.26微米处具有很强的红外特征吸收,符合朗伯比尔定律,通过测量光强度的变化就能换算成混合气体中二氧化碳的含量,进而得出样品中总有机碳的含量。对含有机碳为1.1%的国家一级标准物GBW07423(GSS-09)测试12次,标准偏差为3.45%,对含有机碳为0.45%的一级标准物质GBW07307a(GSD-07a)测试12次,标准偏差为3.10%,对空白测定12次,计算检出限(6δ)为0.004%。

A new method for determination of organic carbon in soil and sediment by high frequency infrared carbon sulfur analyzer are described in this paper. Samples were pretreated by hydrochloric acid to remove the inorganic carbon, filter out the acid insolubles and clean it, after being dry, put it into the high frequency infrared carbon sulfur analyzer for burning in the rich oxygen flow, organic carbon was oxidized to CO2, which has strong characteristics of infrared absorption at 4.26 microns and conforms to the lambert beer's law, we can get the content of the carbon dioxide in the mixed gases by measuring the change of light intensity, then the total organic carbon content in the sample are obtained. The standard deviation is 3.45% and 3.10% by testing the GBW07423(GSS- 09)and GBW07307a(GSD- 07a)for 12 times respectively. The detection limit was 0.004% by testing blank for 12 times and calculating by six sigma.