论文部分内容阅读
目的:建立高灵敏度的检测乳糖中痕量残留蛋白的含量。方法:采用离子选择性凯氏定氮法对乳糖中残留蛋白的含量进行测定。结果:离子选择性凯氏定氮法有较高的灵敏度(其最低检出限在0.06μg·mL-1,而传统的凯氏定氮法最低检出限大多在毫克水平),且在0.2～100μg·mL-1范围内氨气敏电极测定的毫伏数与蛋白质中的氮含量有较好的线性关系;高、中、低3个浓度水平的平均回收率分别为99.9%,99.3%,99.0%;精密度考察RSD为1.4%。结论:离子选择性凯氏定氮法检测限低,简便、快捷,适用于乳糖中痕量蛋白的测定。
Objective: To establish a highly sensitive method for the determination of trace residual protein in lactose. Methods: The content of residual protein in lactose was determined by ion-selective Kjeldahl method. Results: Ion-selective Kjeldahl method had higher sensitivity (the detection limit was 0.06μg · mL-1, while the lowest detection limit of traditional Kjeldahl method was at mg level) The millivolts measured by ammonia gas sensor showed a good linear relationship with the nitrogen content in the range of -100μg · mL-1. The average recoveries of the three concentrations were 99.9%, 99.3% , 99.0%; RSD of 1.4%. Conclusion: The detection limit of ion-selective Kjeldahl method is low, simple, rapid and suitable for the determination of trace proteins in lactose.