Dpt. of Analytical Chemistry, Research Institute of Chemical and Biological Analysis, University of Santiago de Compostela, Spain.
Centre for Information Technologies, University of Santiago de Compostela, Spain.
J Chromatogr A. 2020 Jan 4;1609:460439. doi: 10.1016/j.chroma.2019.460439. Epub 2019 Aug 7.
A novel approach based on the use of desirability functions is presented for the robustness assessment of liquid chromatographic separations as derived from computer-assisted methods development processes. The approach is based on generally accepted hypothesis that a robust separation procedure will be inert to small random variations of the operational variables, typically encountered in the day-to-day routine analytical practice. This means that peak positions along the chromatograms must keep standstill or move insignificantly when operational variables are not intentionally changed. Thus, the degree of peak positions variation as evaluated from mathematical retention models can be used to assess the robustness of the developed procedures before testing the actual performance experimentally. In the approach proposed, this assessment is obtained by fixing a bilateral partial desirability window around each peak in the simulated chromatogram. The whole chromatogram robustness is characterized by an overall desirability value calculated as the geometric mean of the partial desirability windows evaluation. An added advantage of this approach is that the robustness value calculated is normalized between zero and one and thus, easy to interpret. Thus, when chromatograms are simulated and small random variations are introduced into the operational factors of the model, values for the overall desirability close to one means that the procedure performs robustly. On the contrary, low values for the overall desirability clearly indicated a serious lack of robustness. When used in conjunction with the Pareto optimality approach, as shown here, this robustness assessment strategy allows testing several Pareto front solutions before the final experimental testing which is always needed. In this way, a dramatical reduction of the experimental effort is obtained. Although the approach is theoretically applicable to any chromatographic separation, examples of reversed phase liquid chromatographic procedures are used to show the performance of the proposed methodology.
提出了一种基于可接受性函数的新方法，用于评估计算机辅助方法开发过程中得到的液相色谱分离的稳健性。该方法基于一个普遍接受的假设，即稳健的分离程序对于操作变量的小随机变化是惰性的，这些变化通常在日常分析实践中遇到。这意味着当操作变量没有被有意改变时，色谱图上的峰位置必须保持静止或移动不显著。因此，从数学保留模型评估的峰位置变化程度可用于在实验测试实际性能之前评估开发程序的稳健性。在所提出的方法中，通过在模拟色谱图中的每个峰周围固定双边部分可接受性窗口来进行这种评估。整个色谱图的稳健性由整体可接受性值表示，该值是通过计算部分可接受性窗口评估的几何平均值得到的。该方法的一个额外优点是，计算出的稳健性值在零到一之间归一化，因此易于解释。因此，当模拟色谱图并向模型的操作因素引入小的随机变化时，整体可接受性值接近一意味着程序稳健地运行。相反，整体可接受性值低明显表明严重缺乏稳健性。当与帕累托最优方法结合使用时，如这里所示，这种稳健性评估策略允许在最终实验测试之前测试几个帕累托前沿解决方案，这始终是必要的。这样，可以大大减少实验工作量。虽然该方法在理论上适用于任何色谱分离，但反相液相色谱程序的示例用于显示所提出方法的性能。
