Eco-Friendly Capillary Electrophoresis for Enhanced Detection of Hydrophobic Flavonoids in Tangerine Peel Tea via Borate Complexation and Micellar Stacking.

Abstract

Introduction: Tangerine peel tea, a bioactive-rich plant beverage containing hydrophobic flavonoids (hesperidin, naringin, and neohesperidin), faces analytical challenges in quality control due to poor aqueous solubility.

Objectives: In order to determine the hydrophobic flavonoids components in tangerine peel tea and evaluate its quality, this experiment was carried out.

Method: An eco-friendly offline-online capillary electrophoresis stacking strategy integrating polyethylene glycol (PEG)-based aqueous biphasic extraction with borate complexation-assisted micelle-to-cyclodextrin stacking was developed. Critical parameters influencing separation, enrichment, and extraction efficiency were systematically optimized. The method was subsequently validated for accuracy, precision and green evaluation.

Results: Following single-factor optimization, the online stacking parameters were defined as 90 mmol/L sodium tetraborate and 35% (v/v) methanol in the background solution, with injection times fixed at 40 s (SDS), 20 s (cyclodextrin), and 200 s (sample). Offline pretreatment employed a salt PEG sample aqueous biphasic system (ABS) for extraction. Under optimized conditions, the method demonstrated excellent linearity (r ≥ 0.998) and low detection limits (40-50 ng/mL), achieving a 723-fold sensitivity enhancement over conventional detection. Greenness assessment confirmed superior sustainability, and the method successfully quantified three hydrophobic targets (hesperidin, naringenin, and neohesperidin) in tangerine peel tea and spiked rat urine with high accuracy.

Conclusion: The proposed strategy establishes a robust analytical platform for nutraceutical quality control, resolving critical challenges in quantifying poorly soluble bioactive compounds through optimized online stacking and aqueous biphasic extraction.