A rosin derivative-modified silica mixed-mode stationary phase for food additive analysis and natural medicines...

Rosin, as a natural product, offers a novel approach for synthesizing stationary phase materials in liquid chromatography, owing to its advantages of being environmentally friendly, non-toxic, sustainable, and biocompatible. In this study, maleopimaric acid glycidyl methacrylate ester 3-dimethylaminopropylamine imide (MPAGN) was bonded to the silica surface to prepare a chromatographic stationary phase material (Si-MPAGN) featuring reversed-phase, hydrophilic interaction, and ion-exchange mixed-modes. Multiple characterization techniques were employed to verify the successful grafting of rosin derivatives onto the silica surface. The column exhibits multiple interactions, including hydrophobic, π-π stacking, hydrogen bonding, hydrophilic, ion-exchange, and electrostatic repulsion, which collectively enable the highly selective separation of compounds such as alkylbenzenes, nucleotides/bases, benzoic acid derivatives, anilines, polycyclic aromatic hydrocarbons (PAHs), and phenols. Repeatability tests demonstrated excellent stability, with relative standard deviation (RSD) values for both intra-day and inter-day analyses consistently below 0.42 %. Moreover, the column successfully quantified food additives such as sodium benzoate and potassium sorbate, and efficiently separated complex natural medicines, including camptothecin and Panax notoginseng saponins. Under identical chromatographic conditions, the novel stationary phase demonstrated superior performance for the selective separation of mixed analytes compared to commercial C18, amino, and strong anion-exchange (SAX) columns. Quantum chemical calculations incorporating electrostatic potential (ESP) and independent gradient model based on Hirshfeld partition (IGMH) further revealed that the separation of food additives is predominantly driven by electrostatic interactions, while the separation of natural medicines mainly relies on hydrogen bonds combined with van der Waals interactions. These findings confirm the wide applicability of this material to diverse analytes, highlighting its promising potential in analytical chemistry.