金属有机化合物中全铁测定方法研究

Improvement of Potassium Dichromate Method for Determination of Total Iron in Metalorganic Compounds

本文研究了金属有机化合物中全铁测定的无汞盐方法的各种条件。拟定用硝酸分解有机化合物,用高氯酸除去过量硝酸,在盐酸介质中以铝粉还原三价铁,以重铬酸钾标准溶液滴至终点(二苯胺磺酸钠指示剂)。用二茂铁标准试样检验方法可靠性,证明结果准确度符合要求。

Weigh a suitable amount of sample (containing about 20mg of Iron)and put it into a 50 ml flask where there are a few glass beads. Add 10 ml of nitric acid to the sample, place the flask on an electric hot plate and heat the flask until NO_2 ceases to evaporate. Then add 1 ml HCIO_4 to cause the sample to evaporate again until HCIO_4 fume appears. After the sample cools down, add 6 ml HCI, 10 ml water and transfer all the sample to a 250 ml flask, with Alumimum powder as a reducing agent, Fe^(3+) is reduced to Fe^(2+). Determine the total iron with Potassium dichromate method, This method not only keeps the advantage of the K_2C_2O_7 method, but also eliminates the pollution of Mercuric salt. It is rapid, simple and accurate.