Temperature-assisted solute focusing with sequential trap/release zones in isocratic and gradient capillary liquid chromatography: Simulation and experiment.
Temperature-assisted solute focusing with sequential trap/release zones in isocratic and gradient capillary liquid chromatography: Simulation and experiment.
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等度和梯度毛细管液相色谱中具有连续捕获/释放区的温度辅助溶质聚焦：模拟和实验。
DOI：
10.1016/j.chroma.2016.10.062
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发表时间：
2016
期刊：
影响因子：
--
通讯作者：
Weber,StephenG
中科院分区：
文献类型：
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作者：
Groskreutz,StephenR;Weber,StephenG
在这项工作中，我们描述了一种增强温度辅助的柱上溶质聚焦(TASF)的方法的发展，称为两阶段TASF。建立了一种新的仪器来实现两级TASF，由三个独立的电子控制的Peltier器件(热电制冷器，TEC)组成的线性阵列。样品被装载到色谱柱上，前两个TEC，TECA和TECB，COLD。在两级TASF方法中，TECs A和BE在注射过程中被冷却。TECA在样品加载后加热。在TECA温度升高后的某个时间，TECB的温度从聚焦温度升高到与TECA匹配的温度。进样带在柱上聚焦两次，第一次聚焦在初始的TEC上，例如单级TASF，然后重新聚焦在第二次冷TEC上。我们的目标是详细了解两阶段TASF方法。我们开发了一个简单而强大的数字模拟程序来模拟两个聚焦区温度变化对保持、能带形状和能带扩展的影响。该模拟可以预测空间和时间温度程序与等度和溶剂梯度洗脱相结合所产生的实验色谱图。为了评估两阶段TASF方法和模拟的准确性，需要得到表征良好的溶质。因此，在六个温度(25-75℃)下，测定了十二种流动相组成(0.05-0.60乙腈/水)中正构烷基羟基苯甲酸酯和正构烷基对羟基苯酮同系物的保留因子。模拟结果准确地反映了实验结果，表明两级分离方法提高了分离质量。例如，与单级TASF相比，两级TASF将低保留溶质的灵敏度提高了2.2倍，相对于使用等温洗脱的等温条件，灵敏度提高了8.8倍。两级TASF的梯度洗脱结果更令人鼓舞。对于四倍柱体积的进样，两级TASF的应用使试验混合物中保留最少的溶质的峰高相对于单级TASF增加了3.2倍，与等温条件相比增加了22.3倍。TASF提高了分离度和峰容量；对于12分钟的分离，峰容量从等温条件下的75增加到单级TASF的146和两级TASF的185。
In this work we characterize the development of a method to enhance temperature-assisted on-column solute focusing (TASF) calledtwo-stage TASF. A new instrument was built to implement two-stage TASF consisting of a linear array of three independent, electronically controlled Peltier devices (thermoelectric coolers, TECs). Samples are loaded onto the chromatographic column with the first two TECs, TECAand TECB, cold. In the two-stage TASF approach TECsAandBare cooled during injection. TECAis heated following sample loading. At some time following TECA’s temperature rise, TECB’s temperature is increased from the focusing temperature to a temperature matching that of TECA. Injection bands are focused twice on-column, first on the initial TEC, e.g. single-stage TASF, thenrefocusedon the second, cold TEC. Our goal is to understand the two-stage TASF approach in detail. We have developed a simple yet powerful digital simulation procedure to model the effect of changing temperature in the two focusing zones on retention, band shape and band spreading. The simulation can predict experimental chromatograms resulting from spatial and temporal temperature programs in combination with isocratic and solvent gradient elution. To assess the two-stage TASF method and the accuracy of the simulation well characterized solutes are needed. Thus, retention factors were measured at six temperatures (25–75 °C) at each of twelve mobile phases compositions (0.05-0.60 acetonitrile/water) for homologs ofn-alkyl hydroxylbenzoate esters andn-alkylp-hydroxyphenones. Simulations accurately reflect experimental results in showing that the two-stage approach improves separation quality. For example, two-stage TASF increased sensitivity for a low retention solute by a factor of 2.2 relative to single-stage TASF and 8.8 relative to isothermal conditions using isocratic elution. Gradient elution results for two-stage TASF were more encouraging. Application of two-stage TASF increased peak height for the least retained solute in the test mixture by a factor of 3.2 relative to single-stage TASF and 22.3 compared to isothermal conditions for an injection four-times the column volume. TASF improved resolution and increased peak capacity; for a 12-min separation peak capacity increased from 75 under isothermal conditions to 146 using single-stage TASF, and 185 for two-stage TASF.