甘氨酸亚铁中游离甘氨酸含量测定方法的研究
关键词：游离甘氨酸；甘氨酸亚铁；非水滴定法；茚三酮；分光光度法
Study on the Determination Methods of Free Glycine Quantity in Ferrous Glycinate
Abstract: The problems of the determination method of free glycine quantity in ferrous glycinate (non-aqueous titration method) were studied. The current method was modified via separating the free glycine from ferrous glycinate with acetic acid, and the accuracy and reliability of the method was improved. Moreover, a novel method based on the ninhydrin reaction was proposed and the experimental conditions were optimized. The concentration of ninhydrin and ascorbic acid are 0.6% and 0.036%, respectively. The reaction temperature is 75 ℃ and the reaction time is 10 min. A calibration curve was obtained and free glycine quantities in ferrous glycinate samples were determined. Compared with the non-aqueous titration, this method shows the advantages of safety, simple and high reliability.
目录
1绪论 2
1.1甘氨酸亚铁在饲料中的应用 2
1.2甘氨酸亚铁中游离甘氨酸测试方法的研究现状 2
1.2.1甘氨酸亚铁中游离甘氨酸的国标 2
1.3茚三酮分光光度法检测游离氨基酸 4
1.3.1甘氨酸及茚三酮的理化常数 4
1.3.2茚三酮分光光度法检测游离氨基酸的反应机理 5
1.3.3 显色条件的选择 6
1.4研究目的和内容 6
2实验内容 7
2.1非水滴定法 7
2.1.1仪器 7
2.1.2试剂 7
2.1.3甘氨酸与甘氨酸亚铁的溶解度测定 7
2.1.4高氯酸标准液标定 8
2.1.5游离甘氨酸含量测定 8
2.2茚三酮分光光度法 9
2.2.1仪器 9
2.2.2试剂 9
2.2.3显色反应最佳条件及标准曲线的确定 10
2.2.4试剂样品中游离甘氨酸含量测定 10
3.结果和讨论 11
3.1非水滴定法 11
3.1.1 高氯酸标准液的配制与标定 11
3.1.2 国标方法测定样品 11
3.1.3 甘氨酸亚铁中游离甘氨酸的分离 12
3.1.4 改进后的国标方法测定样品 12
3.2茚三酮分光光度法 13
3.2.1紫外吸收光谱 13
3.2.2水浴时间的影响 14
3.2.3水浴温度的影响 15
3.2.4茚三酮用量的影响 15
3.2.5抗坏血酸用量的影响 16
3.2.6标准曲线及实际样品的测定 17
4结论 19
致 谢 20
参考文献 21
1绪论
1.1甘氨酸亚铁在饲料中的应用
甘氨酸亚铁是营养性饲料添加剂，在饲料中为防治动物贫血症、获得最佳免疫水平、健康生长提供了一条高效、安全、简便的途径。与第一代(无机酸铁盐)和第二代(有机酸铁盐)相比，甘氨酸亚铁具有稳定性好，易吸收，无铁腥，无胃肠刺激，无毒副作用，生物利用率高等特点，是最新一代补铁添加荆，能为畜禽同时补充铁和甘氨酸，提高动物适口性。甘氨酸亚铁的动物学效价主要表现如下[1]：
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