改性明胶已经被广泛地用作感光乳剂的沉降剂。然而对其沉降作用的机理,人们却还了解得很少。改性明胶的等电点,是影响改性明胶沉降的重要因素之一。我们采用等电聚焦的新技术,经过适当的改变,成功地测定了改性明胶的等电点及其分布。所得等电点分布的数值,能较好地说明改性胶为什么只有在确定的pH范围内才能进行沉降。 Modified gelatin has been widely used as a photographic emulsion precipitation agent. However, people understand the mechanism of its sedimentation very little. The isoelectric point of modified gelatin is one of the important factors that affect the sedimentation of modified gelatin. We use the new technology of isoelectric focusing, with appropriate changes, successfully measured the modified gelatin isoelectric point and its distribution. The resulting isoelectric point distribution of the value, can better explain why the modified plastic settlement only in a certain pH range.