De Luca Chiara, Compagnin Greta, Nosengo Chiara, Mazzoccanti Giulia, Gasparrini Francesco, Cavazzini Alberto, Catani Martina, Felletti Simona
Department of Chemical, Pharmaceutical and Agricultural Sciences, University of Ferrara, via L. Borsari 46, Ferrara, 44121, Italy.
Department of Drug Chemistry and Technology, "Sapienza" Università di Roma, P.le A. Moro 5, Rome, 00185, Italy.
Anal Bioanal Chem. 2024 Mar;416(8):1809-1820. doi: 10.1007/s00216-024-05186-z. Epub 2024 Feb 15.
The existence of slow adsorption-desorption kinetics in chiral liquid chromatography is common knowledge. This may significantly contribute to worsening the efficiency and kinetic performance of a chromatographic run, especially when high flow rates are employed. Many attempts and protocols have been proposed to access this term, the so-called , but they are based on different (theoretical) assumptions. As a consequence, no official method is available for the estimation of the adsorption-desorption kinetics term. In this work, a novel approach to access is presented. This procedure combines experimental results obtained with kinetic and thermodynamic measurements. The investigations have been performed on two zwitterionic teicoplanin chiral stationary phases (CSPs) based on 1.9 m fully porous and 2.0 m superficially porous particles (FPPs and SPPs), using Z-D,L-Methionine as probe molecule. Kinetic studies have been performed through the combination of both stop-flow and dynamic measurements, while adsorption isotherms have been calculated through Inverse Method. This study has confirmed that, on both particle formats, analyte diffusion on the surface of the particle is negligible, meaning that adsorption is localized, and it has been demonstrated that adsorption-desorption kinetics is strongly dependent on particle geometry and, in particular, on the loading of chiral selector. These findings are fundamental not only to unravel novel aspects of the complex enantiorecognition mechanism but also to optimize the employment of CSPs for ultra-fast and preparative applications.
在手性液相色谱中，缓慢的吸附 - 解吸动力学的存在是众所周知的。这可能会显著降低色谱运行的效率和动力学性能，尤其是在采用高流速时。已经提出了许多尝试和方案来评估这个所谓的项，但它们基于不同的（理论）假设。因此，目前尚无官方方法可用于估算吸附 - 解吸动力学项。在这项工作中，提出了一种评估该项的新方法。该方法结合了通过动力学和热力学测量获得的实验结果。使用Z - D，L - 蛋氨酸作为探针分子，对基于1.9μm全多孔和2.0μm表面多孔颗粒（FPPs和SPPs）的两种两性离子替考拉宁手性固定相（CSPs）进行了研究。通过停流和动态测量相结合的方式进行了动力学研究，同时通过反演法计算了吸附等温线。这项研究证实，在两种颗粒形式上，分析物在颗粒表面的扩散都可以忽略不计，这意味着吸附是局部化的，并且已经证明吸附 - 解吸动力学强烈依赖于颗粒几何形状，特别是手性选择剂的负载量。这些发现不仅对于揭示复杂对映体识别机制的新方面至关重要，而且对于优化CSPs在超快速和制备应用中的使用也至关重要。
