High-throughput and reliable assessments of the ionization constant of monoprotic organic acids through an arginine based mixed mode HPLC

Russo, Giacomo; Kajtazi, Ardiana; Vallaro, Maura; Surmont, Pieter; Ermondi, Giuseppe; Anderson, Scott; Grumetto, Lucia; Caron, Giulia; Lynen, Frédéric

Abstract

The charge state of a molecule is the single most prominent attribute ruling out its interactions with the surrounding environment. In a previous study, the retention of acids on the new Celeris™ Arginine (ARG) column was found to be predominantly driven by electrostatics and, specifically, their charge state. Therefore, we analysed 41 compounds in liquid chromatography with ultraviolet detection to study possible relationships between the analytical retention on this phase and the pKa of the acidic solutes. Highly significant relationships were observed indicating either a linear (r 2 = 0.86) or a quadratic (r 2 = 0.89) trend. To improve the throughput of the method, this was transferred to LC mass spectrometry, allowing the analysis of a molecule every 3mins. The developed method was found to be fast, reliable, accurate, easily automatable and simple to set up. Finally, the analytical column’s being industrially manufactured and commercially available offers broad applicability.

• Journal Article Type: Article
• Acceptance Date: Jul 24, 2023
• Online Publication Date: Jul 25, 2023
• Publication Date: 2023-10
• Deposit Date: Jul 30, 2023
• Publicly Available Date: Jul 31, 2023
• Journal: Journal of Pharmaceutical and Biomedical Analysis
• Print ISSN: 0731-7085
• Publisher: Elsevier
• Peer Reviewed: Peer Reviewed
• Volume: 235
• Article Number: 115604
• DOI: https://doi.org/10.1016/j.jpba.2023.115604
• Keywords: PKa assessment, Dissociation constant, Arginine stationary phase, Acidity, High throughput analysis