Shihabi Z K
Pathology Department, Bowman Gray School of Medicine, Wake Forest University, Winston-Salem, NC 27157, USA.
J Chromatogr A. 1996 Sep 13;744(1-2):231-40. doi: 10.1016/0021-9673(96)00132-x.
Many small natural and synthetic peptides can be stacked for capillary zone electrophoresis by dissolving the peptides in a mixture containing acetonitrile and high concentrations of inorganic salts. In many instances one third of the capillary can be loaded with peptides dissolved in a mixture of 2 volumes acetonitrile and 1 volume of 1% sodium chloride leading to about 20-fold enhanced detection. This stacking is dependent on the presence of both salts and acetonitrile. Natural peptides such as enkephalins, angiotensin and insulin chain B in addition to peptides released from the action of proteolytic enzymes on proteins were concentrated by this method. From a practical point of view, the stacking in acetonitrile is more useful since it removes proteins, counteracts the deleterious effects of high concentrations of inorganic ions present in the sample and stops the enzymatic reaction. Furthermore, it allows a larger volume of the sample to be loaded on the capillary increasing the sensitivity of the CE. This stacking produces a greater sample concentration and better resolution than the traditional stacking obtained in aqueous low ionic strength buffers. The mechanism is also different since it is improved by a high concentration of ions in the sample. Furthermore, since proteins are eliminated, the electropherograms are cleaner and the capillary does not require thorough washings between samples, speeding up the analysis and extending the capillary life.
许多小的天然和合成肽可以通过将肽溶解在含有乙腈和高浓度无机盐的混合物中进行毛细管区带电泳堆积。在许多情况下，毛细管的三分之一可以装入溶解在2体积乙腈和1体积1%氯化钠混合物中的肽，从而使检测增强约20倍。这种堆积依赖于盐和乙腈的同时存在。通过这种方法浓缩了诸如脑啡肽、血管紧张素和胰岛素B链等天然肽，以及蛋白水解酶作用于蛋白质释放的肽。从实际角度来看，乙腈中的堆积更有用，因为它能去除蛋白质，抵消样品中高浓度无机离子的有害影响并终止酶促反应。此外，它允许在毛细管上加载更大体积的样品，提高了毛细管电泳的灵敏度。这种堆积比在水性低离子强度缓冲液中获得的传统堆积产生更高的样品浓度和更好的分辨率。其机制也不同，因为它通过样品中的高浓度离子得到改善。此外，由于蛋白质被去除，电泳图更清晰，并且在样品之间毛细管不需要彻底清洗，加快了分析速度并延长了毛细管寿命。
