摘要
硫是在作物生长过程中必不可少的营养元素之一,主要参与作物生理代谢及生长发育。因此,土壤中硫的含量一直是人们关注的热点,快速准确的检测方法也成为人们研究土壤中硫的关键。在高温燃烧碘量法测定土壤硫含量中,碘酸钾溶液滴定亚硫酸时,对于低含量样品,滴定终点的判断较为困难。通过大量的实验,采用硫代硫酸钠滴定吸收器中反应后剩余的碘酸钾溶液,滴定终点由蓝色消失为无色。终点便于肉眼的观察,提高了分析结果的准确性和再现性;采用Excel中的Linest函数回归标准物质滴定校准工作曲线,方法简便快速。通过国家一级标准物质的分析验证,结果显示,方法的检出限为50.0mg/kg,方法的相对标准偏差(RSD)小于7%,△lgC<0.03,适用于大批量土壤样品中硫的测定。
The method for the determination of sulphor content in soil by combustion iodimetry is difficult to judge the titration end point,when sulfurous acid titrated by potassium iodate in the low content samples.By a large number of experiments with using sodium thiosulfate to titrate potassium iodate solution remained in absorber,the titration end point started from blue to colorless.The end point was easy to observe,the accuracy and reproducibility of analysis results were improved.The method was simple and rapid by using excel linest function of the standard of material titration to calibrate the work curve.The method had been tested by the determination of sulphor in national standard reference materials and the results showed that the detection limit of this method was 50.0 mg/kg,the precision RSD<7%,and△lgC<0.03.The improved method is suitable for large quantities of soil samples with low sulfur content determination.
作者
马一嘉
罗冰虹
谭凯馨
MA Yijia;LUO Binghong;TAN Kaixin(Provincial Key Laboratory of Mineral Exploration and Utilization,Shaanxi,PRC,Xi'an Testing and Quality Supervision Center for Geological and Mineral Products,The Ministry of Land and Resource,Xi'an,Shaanxi 710054,China)
出处
《中国无机分析化学》
CAS
2018年第6期25-28,共4页
Chinese Journal of Inorganic Analytical Chemistry
基金
陕西省地质矿产实验研究所总工基金(2016-03)
关键词
燃烧碘量法
硫
土壤
终点判断
combustion iodimetry
sulphor
soil
judgment at end point of titration
