照相明胶中铁的化学形态研究

STUDY ON CHEMICAL FORMS OF IRON IN PHOTOGRAPHIC GELATIN USED IN COLOR FILM MAKING

利用凝胶层析-电热石墨管炉原子吸收光谱法对照相明胶中铁的化学形态进行了研究。发现明胶中的铁主要与蛋白结合为大分子,同时也有少量小分子量蛋白铁和游离铁。当向明胶样品申加入微量无机铁盐后,铁仍以游离态存在,未与蛋白结合,因而随着明胶中铁含量明显降低,外界铁的污染必须加以特别注意。在照相乳剂制备中必须同时考虑明胶中铁总量及其存在的化学形态。

Chemical forms of iron in photographic gelatin used in color film making were studied by means of gel filtration-atomic absorption spectrum method. It is shown that most of the iron in photographic gelatin coordinate with protein to form stable large molecular compounds and a litter one is small molecular. The trace inorganic iron salt added in the gelatin exists as protein-free iron form only. The foreign iron pollution, therefore, should be paid special attention when iron content in photographic gelatin is very low. Both total iron content and iron chemical form in photographic gelatin should be considered in photographic emulsion making.