The group concentrates in two main areas: The first is devoted to modelling the retention in liquid chromatography (LC). A simple and powerful polarity model that relates the retention of non-charged analytes to the polarity of both the mobile and stationary phases and the polarity of the analyte has been developed. This model allows the simple transfer of retention data between different chromatographic systems (columns and mobile phases); predicts retention in both isocratic and gradient modes; and can also determine the hydrophobicity of most compounds, including drugs. The retention of ionizable analytes, based on the thermodynamic ionic equilibria in hydroorganic solvents, is also being investigated. This work leads to recommended procedures for the proper measurement of the pH in the hydroorganic mobile phases and allows successful relationships between the retention of acids and bases and working pH, ionic strength and temperature. Additionally, studies concerning the acidity of silanol groups present in silica-based stationary phases have led to a simple method to evaluate this acidity.

The second area of research is focused on capillary electrophoresis (CE) and electrokinetic chromatography (EKC) techniques. Appropriate pH buffers and fast high-throughput methods for the determination of pKa values by CE are developed. Additionally, the EKC research involves the characterization of the solvation properties and selectivity of pseudostationary phases. The ultimate aim is to develop methods to prepare phases (e.g., by mixing two compatible surfactants of different properties) with an appropriate selectivity for a specific analytical separation problem or solvation properties that emulate biological partition processes. Thus, biological properties of drugs and pollutants can be easily estimated from the measurement of retention in the electrokinetic system.

Main researchers: Prof. Elisabeth Bosch and Prof. Martí Rosés

Other permanent members: Dr. Clara Ràfols

Post-doc members: Dr. Elisabet Fuguet and Dr. Xavier Subirats

Ph.D. students: Elisabet Lázaro, Carme Repollés, Adolfo Téllez, Juan Manuel Pallicer, Marta Hidalgo and Elham Shoghi.

Solute-Solvent Interactions Group