An efficient matrix solid-phase dispersion extraction combined with online preconcentration by electrokinetic supercharging in capillary electrophoresis for the sensitive determination of two alkaloids in complicated samples matrix

An efficient off-line and on-line synergistic preconcentration strategy which involves combining micro matrix solid-phase dispersion (MSPD) with electrokinetic supercharging (EKS) in capillary zone electrophoresis (CZE) has been developed for the determination of two alkaloids, lycorine and galanthamine, in complicated matrix samples. This method was comprehensively optimized in terms of the buffer condition, the leading electrolyte (LE), terminating electrolyte (TE), the sample injection in EKS preconcentration, as well as the dispersing sorbent, the sample/dispersing sorbent mass ratio, grinding time, eluting solvent in MSPD procedure. Under the optimum conditions, lycorine and galanthamine, achieved about 1500- and 1200-fold sensitivity improvement respectively when compared to the ordinary injection. A satisfactory correlation coefficient (R2 > 0.9982) was obtained in the range of 10–500 ng/mL. The limits of detection (LODs) for lycorine and galanthamine were 6.0 ng/mL and 8.0 ng/mL, respectively. Moreover, the proposed method was successfully applied in two real samples, rat fecal samples and Bulbus Lycoridis Radiatae, to demonstrate its feasibility. Recoveries in spiked fecal and plant samples were 89.51% to 107.4%. The result showed that the new developed method possessed the great potential in analyzing trace alkaloids in complicated samples matrix.