Jeong Lena N, Sajulga Ray, Forte Steven G, Stoll Dwight R, Rutan Sarah C
Department of Chemistry, Virginia Commonwealth University, 1001 W. Main St., Richmond, VA 23284-2006, USA.
Department of Chemistry, Gustavus Adolphus College, 800 W. College Ave., Saint Peter, MN 56082, USA.
J Chromatogr A. 2016 Jul 29;1457:41-9. doi: 10.1016/j.chroma.2016.06.016. Epub 2016 Jun 6.
High-performance liquid chromatography (HPLC) simulators are effective method development tools. The goal of the present work was to design and implement a simple algorithm for simulation of liquid chromatographic separations that allows for characterization of the effect of injection solvent mismatch and injection solvent volume overload. The simulations yield full analyte profiles during solute migration and at elution, which enable a thorough physical understanding of the effects of method variables on chromatographic performance. The Craig counter-current distribution model (the plate model) is used as the basis for simulation, where a local retention factor is assigned for each spatial and temporal element within the simulation. The algorithm, which is an adaptation of an approach originally described by Czok and Guiochon (Ref. [10]), is sufficiently flexible to allow the use of either linear (e.g., Linear Solvent Strength Theory) or non-linear models of solute retention (e.g., Neue-Kuss (Ref. [36])). In this study, both types of models were used, one for simulating separations of a homologous series of alkylbenzenes, and the other for separations of selected amphetamines. The simulation program was validated first by comparison of simulated retention times and peak widths for five amphetamines to predictions obtained using linear solvent strength (LSS) theory, and to results from experimental separations of these compounds. The simulated retention times for the amphetamines agreed within 0.02% and 2.5% compared to theory and experiment, respectively. Secondly, the program was evaluated for simulating the case where there is a compositional mismatch between the mobile phase at the column inlet and the injection solvent (i.e., the sample matrix). This work involved alkylbenzenes, and retention time and peak width predictions from simulations were within 1.5 and 6.0% of experimental values, respectively, even without correction for extra-column dispersion. The issues of sample/eluent solvent mismatch and solvent volume overload are especially important when considering the challenges of transferring eluent from the first to the second dimension in comprehensive two-dimensional liquid chromatography.
高效液相色谱（HPLC）模拟器是有效的方法开发工具。本工作的目标是设计并实现一种用于模拟液相色谱分离的简单算法，该算法能够表征进样溶剂不匹配和进样溶剂体积过载的影响。模拟在溶质迁移和洗脱过程中产生完整的分析物谱图，从而能够全面地从物理角度理解方法变量对色谱性能的影响。克雷格逆流分配模型（塔板模型）用作模拟的基础，在模拟中为每个空间和时间元素分配一个局部保留因子。该算法改编自最初由佐克和吉奥雄描述的方法（参考文献[10]），具有足够的灵活性，允许使用线性（例如，线性溶剂强度理论）或非线性溶质保留模型（例如，诺伊 - 库斯模型（参考文献[36]））。在本研究中，使用了这两种类型的模型，一种用于模拟一系列烷基苯同系物的分离，另一种用于模拟选定苯丙胺类化合物的分离。首先通过将五种苯丙胺类化合物的模拟保留时间和峰宽与使用线性溶剂强度（LSS）理论获得的预测值以及这些化合物的实验分离结果进行比较，对模拟程序进行了验证。与理论值和实验值相比，苯丙胺类化合物的模拟保留时间分别在0.02%和2.5%的范围内吻合。其次，对该程序进行评估，以模拟柱入口处流动相和进样溶剂（即样品基质）之间存在组成不匹配的情况。这项工作涉及烷基苯，即使不校正柱外扩散，模拟得到的保留时间和峰宽预测值分别在实验值的1.5%和6.0%以内。在考虑全二维液相色谱中从第一维到第二维转移洗脱液的挑战时，样品/洗脱液溶剂不匹配和溶剂体积过载的问题尤为重要。
