明胶大分子的照相性质研究——Ⅲ.穆斯堡尔谱法研究铁离子与明胶蛋白的络合形态

STUDY OF PHOTOGRAPHIC PROPERTY OF GELATIN MACROMOLECULE Ⅲ. STUDY ON THE BINDING STATE BETWEEN IRON IONS AND GELATIN BY MOSSBAUER SPECTROSCOPY

明胶中总含有几个至几十个ppm的微量Fe,这些微量Fe在照相过程中起着复杂的作用,探求其与明胶结合的形态(价态及络合态),不但对于寻求正确的去离子化的工艺条件,而且对于深入了解明胶中微量金属杂质对于照相性能影响的机理,都具有重要的意义。本文应用穆斯堡尔谱法对浓缩后明胶粉末进行了测试,结果表明:明胶中的Fe离子(Fe^(2+),Fe^(3+))不是以游离状态存在,而是以络合状态存在着。明胶与Fe的络合呈多种状态,既有Fe^(2+),也有Fe^(3+),还有介于二价,三价之间的过渡状态(由共振结构所致),以及其它特种状态存在,络合的微化学环境也有差别。

In order to enrich the Iron ions, a gelatin sample solution was precipitated and concentrated via freeze drying method, and then was tested by a AME-50 Mossbauer Supec-trometer. It was shown that the trace Iron ions contained in gelatin sample (Fe2+, Fe3+) exist not in the free state, but are complex with the macromolecule. Different iron valence states are co-existed: Fe2+, Fe3+ and some interim valence between Fe2+ and Fe3+ caused by resonance structure, other special valence are also possible.