Online preconcentration and determination of five alkaloids in Yangxinshi tablet by large‐volume sample stacking and micelle to solvent stacking in cyclodextrin‐modified electrokinetic chromatography

Abstract The two‐step preconcentration technique consisting of large‐volume sample stacking (LVSS) and micelle to solvent stacking (MSS) in cyclodextrin‐modified electrokinetic chromatography (CDEKC) was developed for the analysis of five cationic alkaloids in complex Chinese herbal prescriptions. Relevant parameters affecting separation and stacking performance were optimized separately. Under the optimal LVSS–MSS–CDEKC conditions, less analysis time and organic solvent were required, and the enhancement factors of analytes ranged from 12 to 15 compared with the normal CDEKC separation mode. Further, all validation results demonstrated good applicability and multiple alkaloids (epiberberine, dehydrocorydaline, jatrorrhizine, coptisine and berberine) in Yangxinshi tablet (YXST) have been simultaneously determined. This approach presents powerful potential for the determination of multiple components in complex preparations of Chinese medicine.