分光光度法测定饲料中微量铬的研究

目的]探索分光光度法测定饲料中微量铬的效果。方法]提出采用碘化钾(淀粉)分光光度法测定饲料中微量铬的新方法:样品用HNO3-HClO4湿消解后,用KMnO4将三价铬(Cr3+)氧化为六价铬(Cr6+),在pH值为3.0~4.0时,与KI作用后生成的I3-遇到淀粉形成灵敏度很高的蓝色配合物,在分光光度计波长为590 nm处测定其吸光度。结果]改进后的方法操作简单、测定快速,测定结果的准确度和精密度与标准法一致,相对偏差小于2.0%。结论]该研究为测量饲料中的微量铬提供了一种新方法。

Determination of Trace Chromium in Feed by Spectrophotometry

The objective of the study was to explore the effect of trace chromium in feed by spectrophotometry.The paper put forward a new method of using potassium iodide(starch) spectrophotometry in determination of trace chromium in feed.After the sample was humidified and digested by HNO3-HClO4,use KMnO4 to oxidize trivalent chromium(Cr3+) into hexavalent chromium(Cr6+),then under the condition of pH 3.0～4.0,after the effect of KI,it generated into I-3,and would form high sensitive blue complexes when in contact with the starch,and test the light absorption at the site of 590 nm wave length the spectrophotometer.The improved method was simple in operation and rapid in determination,with determination result was the same as accurate and precise as the standard method,and with a deviation less than 2.0%.The study provided a new method in the determination of trace chromium in feed.