Preparation of a composite monolith with functional graphene oxide and its application in the online enrichment of ursolic acid in medicinal plant

摘要

In this study, a composite poly(functional graphene oxide-co-N-isopropylacrylamide-co-trimethylolpropane triacrylate-co-ethylene dimethacrylate) (poly(f-GO-co-NIPAAm-co-TMPTA-co-EDMA)) monolith was prepared, in which f-GO was added. The obtained monolith was characterized by nitrogen adsorption-desorption isotherm and scanning electron microscopy. The monolith exhibited a homogeneous and continuous structure, good permeability, and large surface area. The composite monolith was used as solid-phase extraction absorbent in conjunction with high-performance liquid chromatography for enrichment of ursolic acid. The calibration equation was y = 73.3980x + 0.2555, and the linear regression coefficient was 0.9987; The calibration curve was ranged from 1 to 700 mu g ml(-1); The limit of detection and limit of quantification values were 0.3 and 1.0 mu g ml(-1), respectively; The intraday and interday precisions were less than 2.6 and 7.4%, respectively. The recovery was in the range of 84.44-111.76%. Moreover, the adsorption amount of ursolic acid on the composite monolith was compared with the monolith without f-GO added and silica gel-C18 adsorbent. The results showed that the composite monolithic column was feasible to be used as an online SPE absorbent, which exhibiting low back pressure, good permeability, and high adsorption capacity. In addition, this method provided the possibility to extract and analyze trace components from medicinal plants.