The study of metabolites in biological samples is of high interest for a wide range of biological and pharmaceutical applications. Reversed phase liquid chromatography is a common technique used for the separation of metabolites, but it provides little retention for polar metabolites. An alternative to C18 bonded phases, porous graphitic carbon has the ability to provide significant retention for both non-polar and polar analytes. The goal of this work is to study the retention and effective diffusion properties of porous graphitic carbon, to see if it is suitable for the wide injection bands and long run times associated with long, packed capillary-scale separations. The retention of a set of standard metabolites was studied for both stationary phases over a wide range of mobile phase conditions. This data showed that porous graphitic carbon benefits from significantly increased retention (often >100 fold) under initial gradient conditions for these metabolites, suggesting much improved ability to focus a wide injection band at the column inlet. The effective diffusion properties of these columns were studied using peak-parking experiments with the standard metabolites under a wide range of retention conditions. Under the high retention conditions, which can be associated with retention after injection loading for gradient separations, D_eff/D_m ∼ 0.1 for both the C18-bonded and porous graphitic carbon columns. As C18 bonded particles are widely, and successfully utilized for long gradient separations without issue of increasing peak width from longitudinal diffusion, this suggests that porous graphitic carbon should be amenable for long runtime gradient separations as well.

生物样品中代谢物的研究引起了广泛的生物和制药应用的高度关注。反相液相色谱是用于分离代谢物的常用技术，但它对极性代谢物的保留很少。作为 C18 键合相的替代品，多孔石墨碳能够为非极性和极性分析物提供显着的保留。这项工作的目标是研究多孔石墨碳的保留和有效扩散特性，看看它是否适合与长填充毛细管规模分离相关的宽注射带和长运行时间。研究了两种固定相在多种流动相条件下对一组标准代谢物的保留情况。该数据表明，多孔石墨碳受益于这些代谢物在初始梯度条件下显着增加的保留（通常> 100倍），这表明在柱入口处聚焦宽注射带的能力大大提高。在各种保留条件下，使用标准代谢物进行停峰实验，研究了这些色谱柱的有效扩散特性。在高保留条件下（这可能与梯度分离注射加载后的保留有关），C18 键合柱和多孔石墨碳柱的D _eff / D _m ∼ 0.1。由于 C18 键合颗粒被广泛且成功地用于长梯度分离，而没有因纵向扩散而增加峰宽度的问题，这表明多孔石墨碳也应该适合长运行梯度分离。