《HPLC/MS在胶类药物质量控制中的应用》的报告，各届反响强烈。今日，分析测试百科网的记者再次走近张博士，详细了解一下这个项目的来龙去脉，看看他又为我们带来些什么?
阿胶，《神农本草经》滋补上品，称“久服轻身益气”。李时珍《本草纲目》：“阿胶，《本经》上品，弘景曰：‘出东阿，故名阿胶’”。自古阿胶与人参、鹿茸并称“滋补三大宝”，滋阴补血，延年益寿。

　　我国历代的医学方书中对阿胶均有记载，可见阿胶在中药领域的地位，我国历版药典对阿胶的原料都做了明确规定-只有使用驴皮制作的胶才是阿胶;但同时药典里却没有明确指出如何检测阿胶样品的来源是否是驴皮。因此，市场上出现了用猪皮、牛皮甚至是皮革下脚料代替驴皮制造“假阿胶”。

在质谱图中区分是双电荷还是二聚体则可以通过分子量差异（如双电荷+2H，二聚体+1H）.
有些化合物在离子化过程中非常容易形成二聚体，这些化合物可能在溶液中就容易形成二聚体。所以可以肯定的是在离子化过程中有些二聚体的形成是由分子性质决定的。包括同类分子间的二聚体，如论文－J. Am. Soc. Mass Spectr. 2003, 14(10): 1116-1122。也可以是不同种类分子间的二聚体，参考－Acta Phys. Chim. Sin. 2005， 21 (09): 1042-1045。（二）在相同的离子源条件下，易形成二聚体的化合物可以通过改变溶剂的方式抑制，如有些在甲醇水溶液中易形成二聚体的化合物可以通过使用THF抑制离子化过程中形成的二聚体，会影响HPLC中目标峰的保留时间。

Liu Tao, Zhang Gui-Feng, Bi Jing-Xiu, Su Zhi-Guo*
Abstract
The clinical effectiveness of succinylated gelatin as a plasma substitute depends on its molar mass and modification degree of its free amino group. In this study, a novel method was developed to determine the modification degree of succinylated gelatin. Succinylated gelatin was derivatized with trinitrobenzenesulfonic acid (TNBS). The molar masses of gelatin and succinylated gelatin were determined before and after derivatization with TNBS using size-exclusion chromatography coupled with multi angle laser light scattering (SEC-MALLS). The modification degree was obtained by estimating the free amino groups of succinylated gelatin before and after succinylation. Human serum albumin was used as a model protein to validate the method. The determined value was consistent with the predicted value. Actual samples were analyzed with the developed method; the mean modification degree of succinylated gelatins was 38%. This research indicates that size-exclusion chromatography multi angle laser light scattering coupled with the trinitrobenzenesulfonic acid derivatization is a feasible method for the determination of the modification degree of succinylated gelatin.

Authors: Tao Liu, Guifeng Zhang, Qingqiang Meng, Guanghui Ma, Zhiguo Su*
Abstract: As one of the most commonly used Traditional Chinese Medicine, donkey-hide gelatin had notable blood replenishing effect, and effect of deferring aging, replenishing calcium and suppressing tumor cells, although the active substance is still not very clear. Fibronectin plays a important role in many physiological functions and some unique fibronectin binding peptides from donkey-hide gelatin may have a potential effect on this functions. In this study, the donkey-hide gelatin was fractionated by fibronectin-Sepharose affinity chromatography. After further desalt and concentration, some unique peptides were obtained and further sequenced by reversed phase high performance liquid chromatography/mass spectra.

刘 涛，张贵锋，周卫斌，苏志国*

中国科学院过程工程研究所生化工程国家重点实验室，北京 100080

琥珀酰明胶作为血浆代用品的临床疗效与其分子量分布和修饰度密切相关。本研究利用高效凝胶过滤色谱-多角度激光散射法(HPSEC-MALLS)并结合2,4,6-三硝基苯磺酸（TNBS）衍生法，探索建立一种测定琥珀酰明胶修饰度的方法。实验利用TNBS将琥珀酰明胶衍生，通过HPSEC-MALLS测定琥珀酰明胶的分子量变化，计算出琥珀酰明胶的修饰度。实验以人血清白蛋白为模型进行了方法验证，结果表明该方法能较好地表征人血清白蛋白在TNBS衍生过程中的分子量变化，实验值与根据其氨基酸组成计算值一致。实验在HPSEC-MALLS测定琥珀酰明胶及TNBS衍生后琥珀酰明胶分子量及分布的基础上，利用凝胶过滤色谱分子量-保留时间拟合曲线，计算得到琥珀酰明胶的自由氨基修饰度为38%。 结果表明利用高效凝胶过滤色谱－多角度激光散射法结合2,4,6-三硝基苯磺酸衍生法测定琥珀酰明胶的修饰度具有可行性。