Carbon nanotube-polymer composite for effervescent pipette tip solid phase microextraction of alkaloids and flavonoids from Epimedii herba in biological samples

An effervescent pipette tip solid phase microextraction based on carbon nanotube-polymer composite micro spheres was developed for the simultaneous extraction and determination of four alkaloids (magnoflorine, epiberberine, palmatine, and jatrorrhizine) and four flavonoids (epimedin A/B/C and icariin) from Epimedii herba in biological samples. In this work, the polymeric sorbent was prepared by incorporating carbon nanotube in sulfonated polystyrene-divinylbenzene microspheres. During the extraction, the dispersion of the sorbents at milligram level was achieved by the in situ generation of carbon dioxide. The effervescence enhanced the interaction between the sorbent and the analytes. Langmuir and Freundlich models were used to evaluate adsorption processes. Under the optimum analytical conditions, the method showed good linearity (3300 mu g L-1), acceptable precision (RSD < 5%), low limits of quantification (1.02-2.98 mu g L-1) and satisfactory recoveries (90.05-99.85%). The proposed method was successfully applied to the analysis of alkaloids and flavonoids from Epimedii herba in cell culture fluids, rat urine and feces obtained at the different time intervals.