Zwitterionic stationary phases: advances and trends in the HILIC chromatography of biomolecules and pharmaceuticals.

Zwitterionic HILIC chromatography has been a fast-growing area in recent years, extensively employed for the separation of diverse polar analytes. It provides increased sensitivity and specificity for compounds that are poorly retained or resolved by traditional reversed-phase HPLC methods, especially highly polar and charged molecules. The development of a new generation of zwitterionic stationary phases, along with the investigation of their interactions with analytes, has enabled advanced metabolomic, proteomic, and glycomic analyses. This paper provides an overview of the development and current trends in zwitterionic HPLC columns, including their chemical properties, characteristics, and types of interactions. Recent advances and the applications of different types of zwitterionic stationary phases in pharmaceutical and biomedical analysis are also discussed. The study covers both commercially available and newly synthesized zwitterionic columns. To date, these columns have been primarily tested on model mixtures of polar compounds, with fewer studies applying them to complex biological samples. Consequently, future work should focus on developing and validating methods for the determination of polar analytes in real-world biological matrices.