5-Cl-PADAB显色树脂相分光光度法测定蒙药中微量Fe(Ⅲ)的研究

Study and Determination of Trace Fe(Ⅲ) with Resin-Phase Spectrophotometry in Mongolian Medicine

本文提出了在pH 6 0 0的HAc NaAc缓冲介质中 ,Fe(Ⅲ )与 5 Cl PADAB生成有色络合物 ,与强酸性阳离子交换树脂交换吸附 ,可进行树脂相分光光度法测定微量Fe(Ⅲ )的实验方法。最大吸收波长为 5 4 0nm ,表观摩尔吸光系数为 1 35× 1 0 5L·mol- 1 ·cm- 1 ,Fe(Ⅲ )含量在 0～ 1 8μg·2 5mL- 1 范围内符合比耳定律。该法可用于蒙药中Fe(Ⅲ )的测定。

Under the buffer medium of HAc-NaAc of pH=6.00, Fe(Ⅲ) and 4-(5-chloro-2-pyridylazo)-1, 3-Diaminobenzene form a colored complex which can be quantitatively absorbed on the strong acid cation exchange resin, and the amount of trace Fe(Ⅲ) is determined by spectrophotometry. The maximum absorption wavelength is at 540 nm, the apparent molor absorptivity is 1.35×105 L·mol -1·cm -1. The Beer′s law is obeyed in the range of 0～18 μg·25 mL -1 for Fe(Ⅲ). The proposed method has been applied to the determination of trace Fe(Ⅲ) in mongolian medicine with satisfactory results.