热分解前处理结合分光光度法快速测定土壤中的硫

通过高温热解将硫从土壤中分离出来,富集到吸收液,利用可见光分光光度法进行测定。对热分解系统参数进行了优化,优化后的参数为:管式炉温度1 000℃,热分解时间35 min,载气流量0.1 L/min,吸收液浓度0.02 mol/L,吸收液体积20 mL。利用累积吸收的方法获得方法检出限为0.006 mg/g,降低了该方法的检出限,提高了检测灵敏度。用于国家标准物质(GBW07425,GBW07454和GBW(E)070041)及3份实际土壤样品测定,结果与标准值相符,对实际土壤的硫加标回收率92.4%~107.5%。此方法能够快速、准确地进行土壤中硫的测定。

Spectrophotometric determination of sulfur in the soil after pyrolysis

Sulfur was separated from soil sample by pyrolysis,and was subsequently determined with visible spectrophotometric method. The optimal conditions for pyrolysis system are 1 000 ℃ for pyrolysis temperature,35 min for pyrolysis time,0. 1 L /min for air flow,0. 02 mol /L and 20 mL for concentration and the volume of absorption solution. The method improve sensitivity for sulfur,and the limits of detection is up to 0. 006 mg /g. The method was successfully applied to the determination of sulfur in soil. The results of recovery tests ranged 92. 4% ～ 107. 5%. The accuracy of method has been verified by using national standard substance（ GBW07425,GBW07454 and GBW（ E） 070041）.