Because of the inherent affinity of proteins for bare, fused silica capillaries, the analysis of protein-containing samples has proven a challenging task for capillary electrophoresis. The adsorption of proteins to the capillary walls effectively changes the zeta potential and thus affects the electro-osmotic flow leading to significant shifts in migration time, peak broadening, and poor reproducibility. While there are several well-known methods to remove proteins from samples prior to the analysis (including precipitation) or to prevent their adsorption to the capillary (semi-permanent coatings), those approaches are often expensive, time consuming, or simply unreliable. Aiming to address these needs, this manuscript reports on the use of pyrolyzed cotton balls, as a simple and widely accessible hydrophobic material to remove proteins from serum samples. The material retains enough flexibility so it can be placed directly into the sample vials and has enough capacity to capture more than 75% of the proteins in the sample (1% dilution of 1 mL of serum). The advantages of the material are demonstrated by performing the analysis of five representative drugs (in serum) by capillary electrophoresis obtaining a change in migration time of only 5 ± 1%, after 10 consecutive runs.

中文翻译：

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用于去除蛋白质的热解棉球：通过毛细管电泳分析血清中的药物

由于蛋白质对裸露的熔融石英毛细管的固有亲和力，已证明对毛细管电泳分析含蛋白质样品是一项具有挑战性的任务。蛋白质对毛细管壁的吸附有效地改变了 zeta 电位，从而影响了电渗流，导致迁移时间发生显着变化、峰展宽和重现性差。虽然有几种众所周知的方法可以在分析之前从样品中去除蛋白质（包括沉淀）或防止它们吸附到毛细管（半永久性涂层），但这些方法通常昂贵、耗时或根本不可靠。为了满足这些需求，这份手稿报告了热解棉球的使用，作为一种简单且可广泛使用的疏水材料，可从血清样品中去除蛋白质。该材料保留了足够的柔韧性，因此可以直接放入样品瓶中，并且有足够的能力捕获样品中超过 75% 的蛋白质（1 mL 血清的 1% 稀释度）。通过毛细管电泳对五种代表性药物（血清中）进行分析，在连续 10 次运行后，迁移时间的变化仅为 5 ± 1%，从而证明了该材料的优势。