铁(Ⅲ)的硅胶H相反射散射光度法研究

Study on the Determination of Iron by Silica Gel H Phase-diffuse Reflectance Spectrometry

本文提出了胡椒基荧光酮 (PIF)硅胶H相反射散射光度法测定铁的新方法。在溴化十六烷基三甲基铵的存在下 ,PIF与铁 (Ⅲ )形成稳定的蓝色配合物并且能被硅胶H吸附 ,其最大反射散射吸收波长位于 6 4 0nm ,铁 (Ⅲ )的浓度在 0～ 2 5ng·mL- 1 范围内呈线性关系 ,方法用于氧化镁中微量铁的测定 ,结果满意。

In this paper a new method for the silica gel H phase diffuse reflectance spectrophotometric determination of iron(Ⅲ) with piperonal fluorine (PIF) has been developed In the presence of cetyltrimethyl ammonium bromide and in a NH 4Cl NH 3·H 2O medium at pH 9 6-10 3,iron(Ⅲ) reacts with PIF to form a stable blue complex which is absorbed by silica gel H with a diffuse reflectance absorption peak at 640 nm The calibration curve is linear over the concentration range 0-25 ng of iron(Ⅲ) in 1 mL The linear regression equation is A R =0 022 1 c -0 005 5( r =0 999 7),where c is expressed as ng per 1 mL.The method has high analytical speed and sensitivity.The effect of a number of foreign ions has been studied by carrying out determing of 200 ng·(10 mL) -1 of iron (Ⅲ),1 mg K +,Na +,F -,Cl -,NO - 3,PO 3- 4,0 6 mg Ca 2+ ,Mg 2+ ,35 μg Sr 2+ ,20 μg Cr(Ⅲ),6 μg Mn 2+ ,4 μg Pb 2+ ,3 5 μg Cd 2+ ,2 5 μg Cu 2+ ,Ag +,1 5 μg Cr(Ⅵ),1 μg Ni 2+ ,0 75 μg Zn 2+ ,Sn 4+ et al don′t interfere with the measurement.The method has been applied to the determination of microamount iron in magnesium oxide with satisfactory results