The application of a difluorophenyl stationary phase embedded with imidazolium ionic liquid in HILIC/RPLC/IEC mixed-mode chromatography

Weiran Sun; Hanlin Zeng; Zhiqiang Xun; Yuxue Chen; Yulei Lu; Lei Zhao; Wenhao Chen; Huanjun Peng; Jingdong Peng

doi:10.1016/j.talanta.2026.129783

The application of a difluorophenyl stationary phase embedded with imidazolium ionic liquid in HILIC/RPLC/IEC mixed-mode chromatography

Talanta. 2026 Apr 8:307:129783. doi: 10.1016/j.talanta.2026.129783. Online ahead of print.

Authors

Weiran Sun¹, Hanlin Zeng¹, Zhiqiang Xun¹, Yuxue Chen¹, Yulei Lu¹, Lei Zhao¹, Wenhao Chen¹, Huanjun Peng¹, Jingdong Peng²

Affiliations

¹ School of Chemistry and Chemical Engineering, Southwest University, Chongqing, 400715, China.
² School of Chemistry and Chemical Engineering, Southwest University, Chongqing, 400715, China. Electronic address: hxpengjd@swu.edu.cn.

PMID: 41967223
DOI: 10.1016/j.talanta.2026.129783

Abstract

Ionic liquids have garnered significant attention in the development of stationary phases for high-performance liquid chromatography (HPLC) due to their core characteristics such as wide electrochemical windows, high ionic conductivity, and strong designability. Furthermore, fluorinated columns are considered ideal for enhancing selectivity and reducing analysis time when separating antioxidants containing aromatic rings or isomers with minimal polarity differences. This study developed a novel stationary phase by integrating fluorophenyl groups with imidazole-based ionic liquids. The stationary phase was comprehensively characterized, its separation mechanism was investigated, and its chromatographic performance was systematically evaluated. This stationary phase operates in a mixed-mode chromatographic system that combines reversed-phase, hydrophilic, ion-exchange and pure water conditions, and can efficiently separate hydrophilic compounds, organic acids, hydrophobic substances and halides. Given the enduring public focus on food safety, the detection of food additives is of paramount importance. Thus, the development of rapid and efficient methods for the separation and quantification of food additives is of paramount significance. HPLC has been extensively utilized in the analysis and detection of food additives. The newly developed stationary phase can simultaneously determine the antioxidants BHA and TBHQ in food samples under mixed-mode chromatographic conditions. Under the conditions of mixed-mode chromatography, this method demonstrates operational simplicity, excellent reproducibility, favorable linearity, and high precision. Therefore, the developed stationary phase exhibits considerable potential for the routine analysis of antioxidants in food products. In summary, the stationary phase performs exceptionally well in the conventional analysis of food antioxidants, showcasing significant application prospects.

Keywords: Antioxidants; Fluorinated ionic liquids; Food analysis; Mixed-mode chromatography.