矿物药金礞石和青礞石中铁元素的价态分析

Analysis of Fe element valence state in mineral medicine Lapis Micae Aureus and Lapis Chloriti

目的:建立化学滴定法分析矿物药金礞石和青礞石中亚铁的含量,进而对两种铁元素进行价态分析。方法:以氢氟酸-硫酸处理两种药材,化学滴定法测定样品中亚铁的含量,在X射线荧光光谱法的基础上,对各铁元素含量进行线性回归分析。结果:氧化亚铁的线性范围在1.08-12.96mg之间,线性方程为:y=0.9832x+0.2919,相关系数为0.9994,重复性的RSD=0.41%,加样回收率为96.19%,亚铁和三价铁元素之间具有显著的相关性。结论:采用化学滴定法测定亚铁的含量,简单可靠,具有较好的准确度和精密度,样品中的三价铁基本由黑云母中亚铁转化而来,因此可用来评价金礞石和青礞石的水化程度。

Objective： Chemical titration method was applied to analyze the content of ferrous iron in mineral drug Lapis Micae Aureus and Lapis Chloriti, and then the valence state of two kinds of iron elements was analyzed. Methods： The two kinds of Chinese herbal medicines were treated with hydrofluoric acid-sulfuric acid, and then chemical titration method was used to determinate the content of ferrous iron. Based on X-ray fluorescence spectrometric method （XRF method）, linear regression analysis was carried out regarding the content of iron element. Results： The range of ferrous linear was between 1.08 and 12.96mg, the linear equation being： y = 0.9832x ＋ 0.2919, the correlation coefficient being 0.9994, the RSD of repeatability being 0.41%, and the sample recovery rate being 96.19%. Obviously, ferrous iron and ferric iron had the remarkable correlation. Conclusion： The chemical titration method, which was used to determine iron content, was simple, reliable and has good accuracy and precision. Since the Ferric iron in samples mostly comes from the ferrous iron of biotite, it can be used to evaluate the degree of hydration of Lapis Micae Aureus and Lapis Chloriti.