土壤中微量铬测定方法的研究

Study on the Determination Metric of Trace Chromium in Soil

采用高锰酸钾氧化、碘一淀粉显色的分光光度法测定土壤中的微量铬。样品消解后．用KMnO4氧化Cr（Ⅲ）为Cr（Ⅵ），以NH4HF2掩蔽Fe^3＋．并控制溶液的pH值在3．0-4．0．与KI作用后生成的I3^-遇到淀粉后形成灵敏度很高的蓝色配合物，在分光光度计波长为590nm处测定吸光度。其测定结果的相对标准偏差小于3．0％，加标回收率在93．4％-103.0％，改进后的方法简单、准确、快速、易于操作。

The method of detemaining trace chromium in soil by using potassium pemmaganate oxidation, iodine-starch-spectrophotometric is tested and researched into. Sample shall be dissolved,with the KMnO4 oxidation cr（m）to Cr（Ⅵ）,Used the NH4HF2 masking Fe^3＋ ,and keep the pH is 3.0-4.0. Iodine and starch form a blue complex. Then with sepeetrophotometer determination its absorbanee in λmax = 590 nm.The relative standard deviation is 〈 3 %, the recovery rate of chromium is between 93.4 % - 103.0 %, The improved method proved to be simple, accurate, quick and operate is easy.