In recent studies, the nature and magnitude of the temperature gradients developed in ultra-high pressure liquid chromatography (UHPLC), were found to be dependent on the heat conductivity properties of the column matrices, but also, on the principle used for controlling the temperature over the column. Here, we investigated the potential of using highly heat conductive diamond-based stationary phases (85 times higher than silica), for reducing the temperature gradients. The stationary phases investigated were a (i) Diamond Analytics FLARE column, based on particles comprised of a graphite core surrounded by a very thin diamond shell, and two silica hybrid columns: (ii) a core-shell silica Kromasil Eternity Shell column and (iii) a fully porous silica Kromasil Eternity XT column. Models were developed based on two-dimensional heat transfer theory and mass transfer theory, which were used to model the temperature profiles and the migration of an analyte band accounting for column efficiencies at different flow rates. For the silica-based columns, using water-controlled temperature mode, the temperature gradients along the column axes are suppressed whereas temperature gradients in the radial direction prevails resulting in decreased column efficiencies. Using these columns with air-controlled temperature mode, the radial temperature gradients are reduced whereas temperature gradients along the column prevails resulting in decreased retention times. With the Diamond FLARE column, there was no loss in column efficiency using the water-controlled temperature mode and the van Deemter curves are almost identical using both temperature control modes. Thus, for the Diamond FLARE column, in contrast to the silica-based columns, there are almost no losses of column efficiencies due to reduced radial temperature gradients independent on how the column temperature was controlled.

在最近的研究中，发现在超高压液相色谱（UHPLC）中开发的温度梯度的性质和大小取决于色谱柱基质的导热性能，而且还取决于控制温度的原理。在列上。在这里，我们研究了使用高导热金刚石基固定相（比二氧化硅高85倍）来降低温度梯度的潜力。所研究的固定相为（i）Diamond Analysis FLARE色谱柱（基于由非常薄的钻石壳围绕的石墨芯组成的颗粒）和两个二氧化硅杂化柱：（ii）核壳二氧化硅Kromasil Eternity Shell色谱柱和（ iii）全多孔硅胶Kromasil Eternity XT色谱柱。基于二维传热理论和传质理论开发了模型，这些模型用于对温度曲线和分析物谱带的迁移进行建模，从而说明了不同流速下的柱效。对于水基温度控制模式的二氧化硅基色谱柱，沿色谱柱轴的温度梯度受到抑制，而径向的温度梯度占主导地位，导致色谱柱效率下降。在空气控制温度模式下使用这些色谱柱，可降低径向温度梯度，而沿色谱柱的温度梯度占优势，从而缩短了保留时间。有了Diamond FLARE列，在水控温度模式下，柱效没有损失，并且在两种温度控制模式下，van Deemter曲线几乎相同。因此，与基于二氧化硅的色谱柱相比，对于Diamond FLARE色谱柱，几乎没有由于降低的径向温度梯度而导致色谱柱效率损失，而与控制色谱柱温度无关。